PTS ELECTRON - americanradiohistory.com · 2019-07-17 · PTS ELECTRON Precision Tuner Service PIS...

PTS ELECTRONPrecision Tuner Service

PIS o announce theGRAND OPENING

of our new Service Centers in

LOf AfIGELECOLUMBUf, OHIO

PHOMIXBOJTOfl

flORFOLKMILWAUKEE

LET US TAKE CARE OF YOUR TUNER PROBLEMS . . .

PTS will repair any tuner-no matter how old or new. Fastest Service -8 hour-in and out the same dayOvernight transit to one of our strategically located plants. Best Quality-you and your customers are satisfied

PTS uses only ORIGINAL PARTS! No homemade or make -do, inferior merchandise (this is why we charg?,for major parts!). You get your tuner back in ORIGINAL EQUIPMENT condition.

PTS is recommended by more TV Manufacturers than any other tuner company and is overhauling more

PTS ELECTRONICS, INC.

VHF. UHF $10.95UV -COMBO 17.95IF-SUBCHASSIS 12.50

Major parts and shippingcharged at cost.

(Dealer net!)

HOME OFFICE BLOOMINGTON, INDIANA 47401 5233 S. Highway 37 Tel. 812-824-9331ALABAMA BIRMINGHAM, ALABAMA 35222 524 32nd St. So. Tel. 205-323-2657ARIZONA PHOENIX, ARIZONA 85061 2412 W. Indian School Rd. Tel. 602-279-8718CALIFORNIA LOS ANGELES, CA., Central 90023 4184 Pacific Way Tel. 213-266-3728

SACRAMENTO, CA., North 95841 4611 Auburn Blvd. Tel. 916-482-6220SAN DIEGO, CA., South 92105 5111 University Ave. Tel. 714-280-7070

COLORADO ARVADA, COLORADO 80001 4958 Allison St. Tel. 303-423-7080FLORIDA JACKSONVILLE, FLA., North 32210 1918 Blanding Blvd. Tel. 904.389-9952

MIAMI, FLA., South 33168 12934 N.W. 7th Ave. Tel. 305-685-9811INDIANA BLOOMINGTON, IND. 47401 5233 S. Highway 37 Tel. 812-824-9331KANSAS KANSAS CITY, KANSAS 66106 . 3116 Merriam Lane Tel. 913-831-1222_OUISIANA METAIRIE, LA. 70003 2914 Wytchwood Dr. Tel. 504-885-2349MARYLAND SILVER SPRINGS, MD. 20910 1105 Spring St. Tel. 301-565-0025MASSACHUSETTS SOMERVILLE, MASS. 02144 52 Holland St. Tel. 617-666-4770

SPRINGFIELD, MASS. 01103 191 Chestnut St. Tel. 413.734-2737MICHIGAN DETROIT, MICH. 48235 13709 W. 8 Mile Rd. Tel. 313-862-1783MINNESOTA MINNEAPOLIS, MINN. 55408 815 Lake St. Tel. 612-824-2333MISSOURI ST. LOUIS, MO. 63130 8456 Page Blvd. Tel. 314.428.1299MEW JERSEY E. PATERSON, NEW JERSEY 07407 158 Market St. Tel. 201-791-6380NEW YORK BUFFALO, NEW YORK 14212 993 Sycamore St. Tel. 716-891-4935NORTH CAROLINA CHARLOTTE, N. CAR. 28205 724 Seigle Ave. Tel. 704-332-8007OHIO CINCINNATI, OHIO 45215 8180 Vine St. Tel. 513-821-2298

COLUMBUS, OHIO 43227 4003 E. Livingston Ave. Tel. 614-237-3820PARMA, OHIO 44134 5682 State Rd. Tel. 216-845-4480

OKLAHOMA OKLAHOMA CITY, OK. 73106 3007 N. May Tel. 405-947-2013OREGON PORTLAND, OREGON 97213 5220 N.E. Sandy Blvd. Tel. 503-282-9636PENNSYLVANIA PITTSBURGH, PA. 15202 257 Riverview Ave. W. Tel. 412-761-7648

UPPER DARBY, PA. 19082 1742.44 State Rd. Tel. 215-352-6609TENNESSEE MEMPHIS, TENN. 38118 3614 Lamar Ave. ' Tel. 901-365-1918TEXAS HOUSTON. TEXAS 77032 4324-26 Telephone Ave. Tel. 713-644-6793

LONGVIEW, TEXAS 75601 Mopac Rd. Tel. 214-753-4334VIRGINIA NORFOLK, VA. 23504 3118 E. Princess Anne Rd. Tel. 804-625-2030WASHINGTON SEATTLE. WASH. 98108 432 Yale Ave. Tel. 206-623-2320WISCONSIN MILWAUKEE, WIS. 53215 3509 W. National Tel. 414-643-8800

We offer you finer, fastk,

I eTuner Service

16 ELECTRONICS, INC.......Number ONE and still trying harder!

(Not a Franchise Company)

1 YEAR

GUARANTEE

S

No

1...tor more details circle 119 on Reader Service Card

GTE Sylvania, Electronic Components Group, 100 First Avenue, Waltham, MA. 02154

The death ofa solid-state deviceneedn't complicate

your life.

You take a look at the job and the brandname's Bigston or Kobekiito or Teaberry orPace.

No problem!Sylvania replacement modules and IC's

fit these brands like a glove. They also fit over122 other brands, including RCA, Panasonic,Sony-and, of course, Sylvania.

For the vast majority of domestic andimported electronic equipment, all youneed is a basic stock of Sylvania ECGTM Semi-conductors. And our new Replacement Guideto show you which ones go where.

For a copy, see your Sylvania distributor.

We're helping you make it.enj SYLVANIA

Repair over 126domestic and importedbrands withSylvania modules and IC's.

JULY 1975, ELECTRONIC TECHNICIAN/DEALER / 1

J.W. PHIPPSEditor1 East First StreetDuluth, Minn. 55802(218) 727-8511

ALFRED A. MENEGUSPublisher757 Third AvenueNew York, N.Y. 10017(212) 754-4382

TOM GRENEYPublishing Director

JOSEPH ZAUHARManaging Editor

MARILYN MACDONALDProduction Manager

JOHN PASZAKGraphic Design

LILLIE PEARSONCirculation Fulfillment

GENE BAILEYManager, Reader Services

LOIS SANDERSPromotion Director

ROZ MARKHOUSEClassified Advertising Manager

CONTRIBUTING EDITORS

JOSEPH J. CARRBERNARD B. DAIEN

MANAGERS

DAVE HAGELIN43 East Ohio StreetChicago, III. 60611(312) 467-0670

CHUCK CUMMINGSAd Space South/West613 North O'ConnorIrving, Texas 75060(214) 253-8678

KEN JORDANDONALD D. HOUSTON1901 West 8th StreetLos Angeles, Calif. 90057(213) 483-8530

CHARLES S. HARRISONCY JOBSON57 Post StreetSan Francisco, Calif. 94104(415) 392-6794

ROBERT UPTONTokyo, JapanC.P.0 Box 1717

ELECTRONICTECHNICIAN/DEALER

July 1975 VOLUME 97 NUMBER 7

THE COVER: The variety of modern capacitors on this month's cover-which includepolarized and nonpolarized electrolytics, ceramics, micas, and polyester -and -polystyrene -film types-is evidence of the fact that advances in electronic technology inevitably lead tospecialization, proliferation and complexity of even a "standard" component such as thecapacitor. Although most advances in technology ultimately produce better performing,more reliable products, they also increase the knowledge and skill requirements ofservicers.

FEATURES

12 CAPACITORS-TYPES, CHARACTERISTICS AND APPLICATIONSShould you replace an electrolytic capacitor with an electrostatic type? How can yousatisfy particular capacitance and working voltage requirements if you can't obtain acapacitor with the needed ratings? Does a larger filter capacitor increase the peakoutput voltage of a power supply? What do the ratings "N750" and "NPO" mean?These and other questions about capacitor characteristics and replacement areanswered in this compendium of facts a service technician should consider whentesting and replacing capacitors. By Joseph Zauhar, ET/D Managing Editor.

20 "EXOTIC" SEMICONDUCTORS-THEORY & TESTINGTechnician -oriented explanations of the theory of operation of UJTs, Diacs, Triacs andSCRs, plus proven procedures for testing each. By Bernard B. Daien, ET/D Contribut-ing Editor.

28 POWERS, LOGS & dBS-A BRIEF REVIEWMost servicing technicians do not need these mathematical tools very often, but forthose infrequent occasions when they do this review of the fundamentals of powers often, common logarithms and decibels should ease the transistion from practicingtechnician to mathematician. By Jack Hobbs & J.W. Phipps.

34 POWER SUPPLY REGULATOR CIRCUITSThe theory of operation and procedures for servicing shunt -type, series -pass,combination and switching regulators. By Joseph J. Carr, ET/D Contributing Editor.

TEKFAX-Admiral color TV Ch. 4M10: Admiral b -w TV Ch. TL6; Magnavox color TVCh. T995: Panasonic color TV Model CT -324; and Trav-Ler b -w TV Ch. TR2-1A/2A.

DEPARTMENTS4 LETTERS 45 NEW PRODUCTS6 TECHNICAL LITERATURE 48 CLASSIFIED ADS9 NEWS OF THE INDUSTRY 50 ADVERTISERS' INDEX

40 TEST INSTRUMENT REPORT 51 READER SERVICE44 TECH DIGEST

MI A HARCOURT BRACE JOVANOVICH PUBLICATION "irp'

HARCOURT BRACE JOVANOVICH PUBLICATIONS. James Milholland, Jr.. Chairman, Robert L. Edgell. President. Lars Fladmark,Senior Vice President. Richard Moeller. Treasurer, John G Reynolds, Vice President. Thomas Greney, Vice President. EzraPincus. Vice President, Bruce B. Howat. Vice President, James Gherna. Vice President.

ELECTRONIC TECHNICIAN/DEALER is published monthly by Harcourt Brace Jovanovich Publications. Corporate offices, 757Third Avenue. New York, New York 10017. Advertising offices: 43 East Ohio Street. Chicago. Illinois 60611 and 757 ThirdAvenue. New York. New York 10017. Editorial. Accourting. Advertising Production and Circulation offices: 1 East First Street.Duluth. Minnesota 55802. Subscription rate: one year. $7: two years. $12. three years. $16 in the United States and CanadaOther countries one year. $15: two years. $24: three years. $30. Single copes: 75 c in the U.S. and Canada: all other countries:$2. Second Class postage paid at Duluth. Minnesota 55806 and at additional mailing offices. Copyright 1975 by HarcourtBrace Jovanovich. Inc. All rights reserved. No part of this publication may be reproduced or transmitted in any form or by anymeans, electronic or mechanical, including photocopy. recording, or any information storage and retrieval system. withoutpermission in writing from the publisher.

POSTMASTER Send Form 3579 to ELECTRONIC TECHNICIAN/DEALER. P.0 Box 6016, Duluth. Minnesota 55806

2 / ELECTRONIC TECHNICIAN/DEALER, JULY 1975

A NEW DIMENSIONhas beenadded to

professionakcolor TVservicing

Thenew

CNROMA

hroma-Line

V1010

0

200

SOUND CARRIER

UNMOO

OFF

Chroma-LineCOLOR -PATTERNGENERATOR

For Faster, EasierColor TV Servicing

MOO.

C r Fatt rn Generat o - model 432CH 3

VIDEO

;OUND

4.5 MHz)

SIMPSON MVP C COMPANY ELGIN, LINOIS 80:20

Model 432

16 "touch command" patterns instantlyavailable in a 4 x 4 pushbutton matrix3 VHF channels: 3, 4 and 7, channels 3 and 4fully crystal controlled2 UHF channels: 23 and 52IF Output: 45.75 MHzComposite Video Output: Sync, patternand soundBuilt-in cable storage compartment

MODEL 432 Complete with two cableassemblies, for Coax and 300" inputs, andOperator's Manual $179.AVAILABLE NOW FROM ELECTRONIC PART DISTRIBUTORS

CH.4

CH.7

IF

45.75 MHz)

POWER

OFF till ON 40

This new Simpson model is an all solid-stateinstrumeit incorporating the latest digitalLSI and SSI technology for maximizedcolor -pattern stabi.ity and reliability. Today'sprofessional TV technicians will appreciateits many extra features and performancecharacteristics.

Sound Output: 4.5 MHz carrier, unmodulatedand 1000 Hz FM modulatedAdjustable RF, IF and Video signal level75 Coax and 300 'I Balun OutputsRed, Blue and Green bun killersTransformer -isolated, line powered, forinstant -ready use

FOR COMPLETE SPECIFICATIONS, WRITE FOR BULLETIN T829

SIMPSON ELECTRIC COMPANv853 Dundee Avenue, Elgin, Illinois 60120(312) 697-2260 Telex: 72-2416 Cable: SIMELCO

...for more details circle 123 on Reader Service Card

14WV,INS

WMi %


346 WaysTo Save OnInstruments!EICO's Test Instruments lineis the industry's mostcomprehensive because eachinstrument serves a specificgroup of professional needs.You name the requirement-from a resistance box to aVTVM, from a signal tracer toa scope, from a tube tester toa color TV generator, etc., youcan depend on EICO to giveyou the best professionalvalue. Compare our latestsolid state instruments at yourlocal EICO ElectronicsDistributor, he knows yourneeds best-and serves yourrequirements with the bestvalues!

"Build -it -Yourself" and saveup to 50% with our famouselectronic kits.For latest EICO Catalog on TestInstruments. Automotive and HobbyElectronics. Eicocraft Project kits.Burglar -Fire Alarm Systems and nameof nearest EICO Distributor. check readerservice card or send 50c for fast firstclass mail service.

EICO-283 Malta Street,Brooklyn, N.Y. 1120730 years of service to the ProfessionalServiceman.

EICO...for more details circle 106 on Reader Service Card


LETTERS

Sources of Information About TVReceivers Sold In Canada

In the Letters department of theMarch 1975 issue of ET/D, Mr. Ruhdescribed the difficulty he had in ob-taining service information and partsfor an AGS TV receiver.

Service data for AGS and most otherTV receivers sold here in Canada canbe obtained from the following source:

RCC Publications461 King St., W.Toronto, Canada M5V 1K8

Other ET/D readers might be in-terested in also learning about the fol-lowing Canadian company whichmarkets a line of replacement parts(tradename ELCOM) for TV receiversmanufactured in Canada:

Lake Engineering Co., Ltd.123 Manville Rd.Scarborough, Ontario

I also want to point out that somereceivers manufactured in Canada bysubsidiaries of U.S. companies are notidentical to the same models manufac-tured in the U.S.

Charles CalvertRadio College Of CanadaToronto, Canada

Mr. P.M. Leyden of St. Catharines,Ontario also sent us the same informa-tion about sources of data forCanadian -built TV receivers. A warm"thanks" to both of these helpfulneighbors up North.-The Editor

Another Formula For ComputingRequired Service Labor Income

With reference to Table 2 in the ar-ticle titled Profitable and CompetitivePricing of Service Labor (page 12, De-cember 1974 ET/D), I would like tosuggest the following simple formulafor calculating the gross service laborincome:Selling Total CostsPrice = 100% - Desired % of Profit

(expressed as a decimal)This formula is widely used in busi-

ness and has the advantage that it canbe used to calculate any desired per-centage of profit. For example, usingthis formula and figures in Table 2:

Gross Service Labor Income =$ 93,784

100% - 20% -$93,784_ $117,2300.8

For a 10 -percent profit the divisorwould be 0.9, and for a 25 -percent pro-fit it would be 0.78, etc.

James M. WillisTexarkana, Texas

ShhhhhhLet's

have itQuiet!

QUIETROT.tt IL It 1. II

,SPRAY -PACKtUBRI-CLEANiR

ForTV TUNERS, SWITCHES,

ti3NTROLS, POTS., RELAYS,ETC14SUREs ER AND

:IFGNEST MAN:iCOLOR AN') h. AND Yr'll, ,f iA*5

"IINALly No: ,t:C ,;ROS1,1

4A1MkFV,EFFic

CAUTION

NET WT. 6 OZ.

Let's cut out the noise fromradio, TV and instrumenttuners, switches, relays, poten-tiometers, slides and othercontrols. Quietrole electroniccleaners and lubricants willcut through all that grit andcrud to banish squeaks, rasps,scratches and whines. Yetthey'll not harm plastics ormetal. Non -inflammable, non-corrosive, non-conductive,with zero effects on capacityand resistance. Quietrole -inspray cans or in eye -dropperbottles. A good way to build ahappier (and bigger) clientele.Buy them from practically anyleading jobber or distributor

Product of

QUIETROLECOMPANY

Spartanburg, South Carolina

._for more details circle 120 on Reader Service Card

RCA Solid State, Box 3200, Somerville. N.J. 08876.

K.Ca ieves

Fix it with SK.The RCA quality replacement.

Count on top quality in SK replacement semi-conductors. Because they carry the name RCA, a topmanufacturer of OEM devices. Same strict AQL stan-dards, same strict Director of Quality Assurance. That'show we protect you from callbacks, soyou can make more profitable use of yourtime. RCA's higher -than -ever 410 to 1replacement ratio will help you save timetoo. Your key to fast, easy replacement is er

RCA's new 1975 SK Replacement Guide.Get your copy at the RCA distributorwhere you buy SK parts. SK 3092 eible &Ar Diode

DEXC.IE pee) or,

1111111.1

isa ".7

SS.cuTimIgTAZ

It's OK if it's sk



TECHNICALLITERATURE

Thyristor/Rectifier DirectoryA 68 - page, pocket - size directory

describing over 500 RCA thyristorsand rectifiers is now available. TheThyristor/Rectifier Pocket Directory,TRP - 440A, tabulates the thyristors(SCR's, ITR's, and triacs), discs, andrectifiers available from RCA, andclassifies these devices according tovoltage and current ratings, gate

charateristics and package styles.Also included are type - number cross -reference information for RCA's newdevice numbering system, applica-tions information charts and a list ofRCA sales offices and distributors.RCA Solid - State Division, Box 3200,Somerville, NJ. 08876.

Signal Source Test Instruments

A new, 6 - page, fold - out, short -form catalog is available describing 31different models of signal source in-struments which include: functiongenerators, phase generator, fre-quency synthesizers, and complex -

WHEN YOU'VE GOTSOLID STATE SENSITIVITY

IN A 5" GENERAL SERVICESCOPE WI1H

&TV -H... YOU'VE GOT

;'

LEADER .

c

e

(910

What's more, the LBO -511 delivers calibratedvertical input along with rock -like stability,recurrent sweep and automatic synchronization.This outstanding wideband oscilloscope:vec-torscope is the newest in a series of solid stateinstruments, Leader developed to give you morefor your money. Sweep frequency is in 4 rangesfrom 10Hz to 100Hz and we've added a versatilephasing control, continuous from 0 to 140 .

Overall sensitivity is 20mVp-p cm to 10Vp-p cm

o

and vertical input is calibrated. The solid-statestability and distortion -free displays are theresult of Leader's exclusive FET input stages plusDC coupling and push-pull amplifiers. Bandwidthis DC to 10MHz. And, there are special inputs toobtain vectored pattern displays for color TV cir-cuit testing. Complete with probe, adapter andtest leads, the LB0511 weighs just 15 lbs. andis unusually compact.

"Put us to the test"

$299.as

LEADER151 Dupont Street, Plainview, L.I., N.Y. 11803 (516) 822-9300INSTRUMENTS CORP



waveform synthesizers. This catalogalso contains a model capability cross -reference chart and prices. Exact Elec-tronics, Inc., Box 160, Hillsboro, OR.97123.

Test Equipment

A 16 - page catalog covers a varietyof test equipment, including two newVOM's - the Model 310, Type 3 andthe Model 615. The catalog, No. 60 - T,covers Triplett's full range of productsfrom general, multi - purpose VOM'sthrough laboratory and special fea-tures testers temperature testers andaccessories. It contains a handy selec-tion guide chart, designed to helpselect a tester for specific require-ments, and lists both sales representa-tives and service modifications cen-ters. Dept. PR, Triplett Corp.,Bluffton, Ohio 45817.

Che-nical Products

A new 12 - page catalog of chemicalproducts made exclusively for the elec-tronics industry is now available. Thecatalog features application informa-tion, photos, descriptions, and specifi-cations on chemicals used to speedelectronic servicing and facilitatemaintenance of electronic equipment.Included are tuner sprays, contactcleaners and lubricants, circuit cool-ers, insulating sprays, lubricants,moisture removers and heat sink com-pounds. Chemtronics Inc., 1260 RalphAve., Brooklyn, NY.

Electrical Maintenance Hints

A new hardbound edition of theWestinghouse Electrical MaintenanceHints handbook is now available. The1,450 - page manual is designed toprovide plant maintenance personnelwith a convenient reference source onmaintenance practices for the mostcommonly used types of electrical ap-paratus. It contains 46 chapters, eachorganized to help the user quickly lo-cate any particular subject. Eachchapter is indexed by topic and sub -topics, which eliminates the need tocompletely read or review the entirechapter to obtain information on aspecific subject. It also contains photo-graphs, diagrams, charts, tables andtest procedures. Price is $15.Westinghouse Electric Corp., PrintingDivision, P.O. Box 398, Trafford, PA.15085.

Electronic Parts Catalog

A 32 - page 100 AnniversaryCatalog featuring a beat inflationsales of electronic parts is available.For your free catalog, write to B&FEnterprises, 119 Foster Street, Pea-body, MA. 01960.0

Type EVthe space -saver lytic 0.001)0,0.0.0000 0.i)

board roomFor space -saving lytic capacitor replacements on crowded printedwiring boards found in most of today's foreign and domestic consumerentertainment products, Sprague Type EV Verti-Lytic® Capacitors havethe widest range of values . . . in the smallest case sizes . . . of anysingle -ended capacitors available anywhere!

Get on Board with the KE-17 AssortmentThis handy assortment of 61 Type EV Capacitors in the 27 most -popular ratings gives you an on -the -spot inventory of thereplacement capacitors you need for most of the sets you'llencounter. Sturdy blue plastic cabinet has nine pre -labeleddrawers for fast, easy selection. And you pay for capacitors only... the cabinet is yours at no extra cost!

See these "new era" capacitors at your Spraguedistributor's. Or, get the full story by writing forBrochure M-951 to: Sprague Products Co., 65 MarshallStreet, North Adams, Mass. 01247.

6S 2114

THE BROAD LINE PRODUCER OF ELECTRONIC PARTS...for more details circle 124 on Reader Service Card

JJLY 1975, ELECTRONIC TECHNICIAN/DEALER 17

SPRAGUE®THE MARK OF RELIABILITY

9 new ways to improve tv receptionand your profit -picture.

Whether its a 1000 -set installation at the International Hotel in Las Vegas... or a basic 4 -set home TVsystem, there's a Blonder -Tongue MAN product that will deliver better TV reception.

Here are 9 new products backed by 25 years of experience in improving TV reception.

1 AB -300, 25dB gain C h 2-13, FM. Dual voltage power for short or long 25dB loss runs of 75 ohm or 3000 ohm

downlead.

2. DA8-T-famous DA8B fully transistorized. l'g13dB gain. Lower noise. 1 input/8 outputs. ei -VHF/FM. Universal 300 ohm/75 ohm.

3 DA-21-21dB gain, 75 ohm. VHF/ FM and all CATV channels to. 300 MHz.

4 Homer 375 Amplified Splitter-VHF/FM. and all CATV channels to 300 MHz. 3 sets300 ohms and one set at 75 ohms from aCATV cable input.

5 Vamp T-75 Mast -Mounted Preamp-17dB gain. PatentedM ICEF overload protection circuit. 6dB noise figure

75 ohm downlead 2-13.

6 CR-4-Deluxe compound, parallel -jawM crimping plier.

7 Model 4994-75 ohm 2 -way antenna switch. Video, VHF, FMand all CATV channels to 300 MHz.

8 4946 U/V/FM -An economical band separator for TV sets and an FM

takeoff connection.

9 SA -1000 Semi -automatic Rotor. Computer -age LED tuningM indicator. 360° rotation. Economical two -wire installation.

BLONDEFTrONGUEThese new BLONDER -TONGUE products are now at your distributor.

Blonder -Tongue Laboratories, Inc., One Jake Brown Road, Old Bridge, NewJersey 08857...tor more details circle 105 on Reader Service Card

8 / ELECTRONIC TECHNICIAN/DEALER. JULY 1975

NEWS OF THE INDUSTRY

July 15July 17July 28-29-30Aug. 26Aug. 28Sept. 8Sept. 10Sept. 11Sept.*Sept.*Oct.*Oct.*Oct. 21-22-23Nov. 11-12-13

GTE Sylvania Implements New Color TV Picture Tube Labeling System

A new, clearer method of identifying color TV picture tube types has been developedand implemented by the Electronic Components Group of GTE Sylvania.

Under the new system, the grade of the tube is printed clearly on the carton-either"ALL NEW," "NEW SCREEN & GUN" or "NEW GUN." A back-up color code is also usedon each carton, with red indicating "all new," blue indicating "new screen and gun," andgreen indicating "new gun." In addition, two type number prefixes, "AA" for "all new"and "A" for "new screen and gun," are included on the cartons of these types of tubes, toconform to California and Florida picture tube grading regulations.

Winegard MATV Field Training Schedule

The Commercial Products Division offollowing schedule of one- and three-day

Knoxville, Tenn.Dayton, OhioBurlington, Ia.Alexandria, Va.Orlando, Fla.Torrance, Calif.Anaheim, Calif.Tucson, Ariz.Boston -Portland, Mass.Gape Girardeau, Mo.Fargo, N.D.Minneapolis, Minn.Raleigh, N.C.

Fla.

the Winegard Company has announced theworkshop seminars on MATV.

Mr. Jim Williams (404) 469-3450Mr. Roger Good (614) 846-8449Mrs. Sandie Powell (319) 753-0121Mr. Dennis Williams (302) 834-8469Mr. Leo Riddle (813) 293-5070Mr. Ben Hedges (213) 772-1451Mr. Ben Hedges (213) 772-1451Mr. Ben Hedges (213) 772-1451Mr. Dave Johnson (603) 888-0323Mr. Jon Peterson (815) 459-8294Mr. John Jordahl (507) 332-8052Mr. John Jordahl (507) 332-8052Mr. Jim Williams (404) 469-3450Mr. Leo Riddle (813) 293-5070

*Specific date not yet determined but will be at least 45 days in advance.Advance registration for any of the preceding seminars can be made by contacting the

indicated District Manager or by calling James C. Banard, National Sales Manager,Commercial Products Division, Winegard Company, (319) 753-0121, or write him at3000 Kirkwood St., Burlington, Iowa 52601.

RCA, Zenith Presidents Report Increased Color TV Sales Late In 1st Half, Predict ThatUpward Trend Will Continue

RCA President Anthony L. Conrad and Zenith President John J. Nevin both havereported increases in color TV sales during the 2nd quarter, and both believe that thetrend will continue.

RCA's Conrad, speaking before the 56th Annual meeting of RCA shareholders in earlyMay, said that the depressed sales in the color TV industry-a principal cause of RCA'sfirst quarter earnings decline-had been improving in recent weeks, and then added,"The trend from here on should be upward."

Zenith's Nevin at about the same time said, "The worst of the sales decline is wellbehind us. There's no question that there's been a significant upturn of sales to dealers."

121 Million TV Sets In Use

As of 1974, there were 64 million monochrome and 57 million color TV receivers in usein the U.S.. or a total of 121 million TV receivers in use.

These and other statistics and facts about the electronic industry and the productswhich are produced, marketed and serviced by it are reported in the 120 -page 1975Electronic Market Data Book, recently released by the Electronic Industries Association(EIA). Copies of the book can be obtained by nonmembers for $20. Write: 1975 Elect. Mdt.Data Book, EIA, 2001 Eye St., N.W., Washington, D.C. 20006.

Pay TV To Spread By Satellite If FCC Approves

Home Box Office, Inc., a subsidiary of Time Inc., which since 1972 has been providingthe Northeastern States with a single channel of pay -TV programming, reportedly hasmade arrangements with RCA Global Communications for use of its satellite facilities toinitially distribute pay -TV programming to two community antenna TV (CATV) sys-tems in Florida, and eventually to other states in the West and Southwest.

If approved by the Federal Communications Commision (FCC), Home Box Office's planto distribute pay -TV via satellite could become operational as early as this October.

Initially, the pay -TV program will be sent from Home Box Office's central studio andtransmission control center in Manhattan to a satellite transmission system. The satel-


NEWS

lite pay -TV signal will be received by two separate receiving (earth) stations built inFlorida by two large CATV companies: American Television and Communications, andUA-Columbia Cablevision. The signals will then be distributed via microwave to cablesystems in Florida owned by these two companies, and to Florida cable systems owned byother companies.

Later (possibly as early as 1976), UA-Columbia Cablevision also will build earthstations for distribution of satellite pay -TV signals to its CATV systems in Arkansas,Texas, Arizona, California and Washington State.

Wisconsin Service Association Surveys The Incidence of TV Module Replacement

The Wisconsin Electronic Service Association (WESA) recently asked its members tolist the TV modules they replace most.

Following is a list of the modules (or panels) which WESA members say they replacedmost often, with the most frequently replaced under each brand listed first and the restlisted in descending order according to frequency of replacement:

Admiral: M-20 Ch, A8911-1; 3M20 Ch, A8912-2; M24 Ch, A8912-2, A8926-2; M-25Ch, A8919-1, A8920-1, A8921-1, A8923-4, A8924-1, A8926-4; M30 Ch, A8927-3, A8931-1, A8929-1

Motorola: CA, BA, JA, AZ, F(A), GA Philco: 69-1025, 69-1005, 69-1014RCA: 132-581, 132-582, 132-579,134-007, 138-697, 135-871, 133-455, 139-685,

133-563, 132-583, 132-580Sylvania: 02-375000-1,2,3 & 02-37503-1,2 and 3Zenith: 9-27, 9-37, 9-86, 9-87, 9-90, 9-92, 9-97. (Zenith ICs: 150-162, 150-186, 150-190,

221-43).

NATESA Convention August 7-10

The National Alliance of Television and Electronic Service Associations (NATESAwill hold its annual convention August 7-10 at Pheasant Run Resort in St. Charles,Ilinois.

Limousine service from Chicago's O'Hare Airport and the Chicago Loop to PheasantRun is available seven times per day.

The registration fee for the convention is $25.00 per person, and includes sponsoredmeals, refreshments, hospitality suites, banquet and floor show.

For more information about the NATESA Convention, write Frank Moch, NATESA,5908 S. Troy St., Chicago, Ill. 60629.

Washington and Oregon Associations Schedule Joint Convention July 25-27

The Washington State Electronics Council (WESC) and the Oregon Television ServiceAssociation (OTSA) are holding a joint convention July 25-27 at the Jantzen BeachThunderbird Motel in Portland, Oregon.

A two-day business management school will be presented by the Portland CommunityCollege during the convention.

The registration fee for the convention, including the business management school, is$60.00 for servicers and $30.00 for their wives.

More information about the joint convention can be obtained by calling James Rolison(503-282-7751) or Robert A. Villont (208-475-8300).

NESDA Convention August 12-17

The National Electronic Service Dealers Association (NESDA) will hold its annualconvention August 12-17 at the Hyatt House Hotel in Winston-Salem, North Carolina.Registration information can be obtained by writing: NESDA, 1715 Expo Lane, In-dianapolis, Ind. 46224, or phone (317) 241-8160.

PTS Opens New Tuner Service Centers In Ohio and Maryland

PTS Electronics, Inc., Indiana -based TV tuner repair company, recently announcedthe opening of two new service centers, one at 4005A E. Livingston, Columbus, Ohio43227, and 52 Holland St., Davis Square, Sommerville, Maryland 02144.

Senate Passes Consumer Agency Bill

The United States Senate on May 15 passed bill S.200, which, if subsequently passedby the House of Representatives, will create the Agency For Consumer Protection.0


SIIIISTI1L0

U S AONLY

WITH CABLES

ONE YEAR ONLYGUARANTEE

gal

ONLY

ALL PARTSINCLUDED

EXCEPT TUBESAND TRANSISTORS

FEATURES

A UHF Tuner with70 channels which aredetented and indicatedjust like VHF channels.

A VHF Hi GainSolid -State Tuner

AC Powered

90 -Day Warranty

Demonstrate the Fr77177Trzi toyour customers and show improvedreception with their TV sets.

You may place your order throughany of the Centers listed below.

TSC

WATCH USGROW

GEORGIILLINOI

HEADOUARTERSARIZONACALIFORNIA

FLORIDAC

it.

INDIANA

IOWAKENTUCKYLOUISIANAMARYLANDMASSACHUSETTSMISSOURINEVADANEW JERSEY

OHIO

OREGONTENNESSEE

TEXASVIRGINIAWISCONSINCANADA

PROVIDES YOU WITH A COMPLETE SERVICEFOR ALL YOUR TELEVISION TUNER REQUIREMENTS.

VHF OR UHF ANY TYPE (i/ s A ONLY) S 9.95UHF/VHF COMBINATION (U S A ONLY) $15.00 IN THIS PRICE ALL PARTS ARE INCLUDED.Tubes, transistors, diodes, and nuvistors are chargedextra. This price does not include mutilated tuners.

Fast, efficient service at our conveniently locatedService Centers.

All tuners are ultrasonically cleaned, repaired,realigned, and air tested.

UNIVERSAL REPLACEMENT TUNER $12.95 (U S A. only)

This price buys you a complete new tuner built spe-cifically by Sarkes Tarzian Inc. for this purpose.

AII shafts have a maximum length of 101/2"can be cut to 11/2".

Specify heater type parallel and series 450 mA.or 600 mA.

CUSTOMIZECustomized tLners are available at a cost of only

$15.95. With trade-in $13.95. IU.S A. onlyl

Send in your original tuner for comparison purposesto any of the centers listed below.

BLOOMINGTON. INDIANA 47401TUCSON. 1 IZONA 857*

RTH 1.41:4L' f CALIF. 91601B E. CAMOD $ O. CALIF %351

11

TA P. itELQIIID 33.06FT L RDA a7 0 DA 33315A L TA. GEO IA X31

H PAIGN. IL INOISHI A IS 60621

KIE, I

AMMONA

S

LLE.EPORT.

BALTI RE. MSPRINGT LOUIS

LINOINDIA

LIS. INDOINES,

ENT

46ANA 46OWA 50CKY 4

LANDACHUSE1111 6213

411%ii

V AS. DA^4/1 NEW JER!Pf

_1_ U10

JER NEW JCINCIN HIO 45216CLEVELA HIO 44109PORTLAN.REGON 97210

01108

GREENEVILLE. TENNESSEE 37743MEMPHIS. TENNESSEE 38111DALLAS, TEXAS 75218NORFOLK. VIRGINIA 23513MILWAUKEE, WISCONSIN 53216ST. LAURENT. OUEBEC H4N2L7CALGARY. ALBERTA T21 -10L1

537 South Walnut StreetP 0. Boa 4534. 1528 S. 6th Ave.10654 Magnolia Boulevard11.2 len123 %Moen n e1505 Cypres104

vansw2st U

est Brorand An

2920 Tayl3025 Hi

St rer Bouland Ave

Reis05 Dickin

30 Peg1412 ^es901 Nor th II

547-4OTonn7450 Vine S4525 Pearl1732 N.

15

n

on StrAve e

nue No. 1Nen vele v.e,ee

25th Avenueapps Ferry Road

3 8 arron Avenue1154' arland Road3295 Santos Street4722 W. Fond Du Lac Ave.305 Decarie Boulevard448 42nd Avenue S.E.P 0 Boo 5823. Stn. "A"

Tel. 812-334-0411Tel. 6 - 91-9243Tel 2 3- 9.2720

I 5.34 157289- -8051

1 53-03245 4.0914

-2232356-6400

-873-5556-712-675-023019-845-267617-632-3493

515-277-015502-634-333418-221-3027

301-358-1186. 413.788-8206

el. 314-429-0633Tel. 702-384-4235Tel. 609-393-0999Tel. 201-792-3730Tel. 513-821-5080

el. 216.741-2314I. 503.222-9059I 615-639-8451I 901-458-2355

Tel 214-327-8413Tel. 804-855-2518Tel. 414.871-7655Tel. 514-748-8803Tel. 403-243-0971

elTel.Tel.

Te

IF YOU WANT TO BRANCH OUT INTO THE TV TUNER REPAIR BUSINESS.WRITE TO THE BLOOMINGTON HEADQUARTERS ABOUT A FRANCHISE.



Capacitors Types,Characteristics and Applications

Electrostatic and electrolytic capacitors differnot only in their design and construction, but also in their

circuit applications. You should not attempt to replaceelectrostatic types with elect.-olytics and vice versa

Fig. 1-Two of the most commonly used types ofelectrolytic capacitors are the single -endprinted -circuit type shown on the lett in the photoand the tubular axial lead type shown to theright.

Servicing of the vast number ofconsumer home entertainmentelectronic products, both domesticand foreign, can create a problemof parts availability for the elec-tronic technician. Capacitors are agood example, and if the exact re-placement part is not always a-vailable, we must use the correctcapacitor type for the many criti-cal circuits. A better understand-ing of the various capacitor typescan eliminate future difficultiesand improve your effectivenessand profit.

There are many different typesof capacitors, which vary in shape,size and capacitance value. Wemust remember they all have beenconstructed for a specific applica-tion employing materials whichmake them superior to othercapacitors for the particular cir-cuit in which they are employed.

Capacitors can be placed intotwo categories and can be iden-tified as either an electrolytic orelectrostatic type. We must recog-nize what the basic differences arebetween the two capacitor types inboth construction and applica-tions.

ELECTROLYTIC CAPACITORS

Electrolytic capacitors willstore more electrical energy fortheir physical size than any othercapacitor. Instead of the usualplates separated by a dielectric ascompared to the electrostatic type,a very thin film of aluminum oxideis formed on the surface of analuminum anode functioning as adielectric and a liquid electrolyteforms the cathode. A secondmetallic conductor acts as the

By Joseph Zauhar

connection to the liquid cathodeproviding an external connection.

The aluminum and the tan-talum capacitors are two of themost common types found in homeentertainment products. They arebasically constructed in the samemanner, covering the aluminumor tantalum anode with an oxidefilm. The liquid or solid electrolyteis the cathode.

The aluminum -oxide provide avery high resistance to currentflow in one direction and a low re-sistance in the opposite direction.First, the film functions as adielectric and then the plate in thesecond instance.

The two most commonly usedtypes of electrolytic capacitors arethe tubular axial lead and thesingle -end printed circuit -typeshown in Fig. 1 and most commontwist prong "can" (Fig. 2), with oneor more sections with a commoncathode.

Electrolytic Capacitor Tolerances

Because of the electro-chemicalprocesses employed during themanufacturing of electrolyticcapacitors-along with the varia-tion in the etching process-it isdifficult to produce an electrolyticcapacitor close to its intendedcapacitance. This is generally nota problem when replacing acapacitor, because most circuitswill tolerate at least a fifty percentexcess capacitance and in manycases several hundred percent.

A typical electrolytic having atolerance of - 10 percent to + 50percent means that a 100 mfdcapacitor will have an actualcapacitance value of between 90


Fig. 2-The most common aluminum -casedelectrolytic twist prong "can" capacitor with oneor more sections containing a common cathode.

and 150 mfd. To find its exactcapacitance it would have to bemeasured.

Suppose a circuit is designed for60 mfd capacitor, we could replaceit with a 100 mfd to 120 mfd with-out any problems. The thing toremember is that it makes verylittle difference in a filter circuit touse a larger value, but never sub-stitute a capacitor having a lowerrated capacitance than the origi-nal value.

The maximum practical voltagelimit for electrolytics is 450 volts.By employing special processingmethods and careful selection ofmaterial, capacitors have beenproduced with a maximum volt-age rating of 525 volts. Themaximum operating temperaturemust be reduced from 85 degrees C(185 degrees F) to 65 degrees C(149 degrees F) for capacitorsrated at higher voltages. Acapacitor rated above 450 volts at150 degrees F can be operated at185 degrees F when used at 450volts or less.

As the voltage rating of an elec-trolytic increases, the capacitancetolerance becomes less. If a

Fig. 3-The popular disc -type ceramiccapacitor.

Fig. 4-Tubular axial lead ceramic capacitors

capacitor is rated at 1 to 50 voltsDCW at a tolerance of -10 percentto + 250 percent, above 350 voltsDCW, the tolerances would be re-duced to - 10 percent to + 50 per-cent.

When replacing an electrolyticcapacitor, always remember to useone with a capacitance rating of atleast as high as the original onereplaced, and a voltage rating atleast as high.

Electrolytic Capacitor Substitution

Electrolytic capacitors storelarge amounts of energy for theirsize and to replace them with apaper -type capacitor of equalvalue would be difficult with theavailable space. Also, they mayhave some electrical characteris-tics which may cause circuit mal-functions if replaced with thepaper -type.

Paper types cannot be substi-tuted with an electrolytic even ifthey are of equal value. The papertypes were chosen because of theirbetter voltage characteristics, orpolarity -reversal characteristics.The polarity of an electrolyticcapacitor is extremely important

and electrolytics do not providethe close tolerance needed in somecircuits.

Increasing The Capacitance andVoltage of A Capacitor

Often we find a circuit requiringa specific amount of capacitance,but only smaller value capacitorsare available. Suppose you need a60 mfd, 300 volt DCW capacitor,then simply place two 30 mfd, 300volt DCW capacitors in parallel.In some rare cases, we may changethe RC time constant enough tocause problems or the two paral-leled capacitors are too large forthe available space in the chassis,then the exact replacement is re-quired. When connecting twocapacitors in parallel, we increasethe capacitance, but the voltagerating remains the same. Unlikecapacitance, voltages in parallelare not additive.

If we find a circuit requiring ahigher working voltage, we canplace two capacitors in series. Two80 mfd, 150 volts DCW connectedin series will be equal to a single40 mfd, 300 volt DCW. The RCtime constant may change enoughin some rare cases, because the re-sistance is lower in the parallelcircuit and higher in the series cir-cuit than in an equivalent singlecapacitor.

Substituting Non -PolarizedCapacitors

In the event that a non -polarized twist -prong capacitor isrequired, place both positive leadsof two tubular electrolyticcapacitors through the respectivesolder lugs and connect the nega-tive leads together, but do notground them. You should employcapacitors with higher voltageratings and twice the capacity ofthe original. If two 100 mfd, 450volt DC capacitors are connectedback-to-back, we will now have a50 mfd, 300 volt AC non -polarizedcapacitor. This same arrangementcan be usea to replace tubularnon -polarized capacitors.

Electrolytic Capacitor Myths Dispelled

Listed are some of the commonmyths expressed by many elec-tronic technicians concerning thesubstitution of electrolyte capaci-


tors in different electronic circuits: Using a higher value capacitor

in the input filter circuit of thepower supply will increase the out-put voltage. Actually, the purposeof the filter is to smooth the ACripple. Increasing the input filtercapacity will not increase thevoltage higher than the peak ACvoltage.

If the original filter has losscapacity, a new filter capacitorwill increase the voltage, but onlyto the proper specified voltage.

Substitution of an electrolyticwith more capacitance will in-crease leakage. An old capacitorwill normally have more leakagethan a new capacitor with a highercapacity rating. With the excep-tion of some coupling circuits, thisis a minor factor.

Substitution of electrolyticcapacitors of higher capacitance insome coupling circuits will causethem to malfunction. This could betrue if the inductance of thecapacitor has increased because ofthe larger size and more layers ofelectrolyte. The latest manufac-turing process, employing hardaluminum foils, now makes it pos-sible to reduce its size for the samevalue to such a fraction of the orig-inal one that this is no longer animportant factor.

Electrolytic capacitors will de-form at lower voltages or whenstored on the shelf for a period oftime. The capacitors producedabout 10 or 15 years ago weremanufactured with those charac-teristics, but the new capacitorsare stable and will function atlower working voltages withoutdeforming and changing capacity.

The self -life of the newaluminum -cased capacitors areextremely long, as compared tothe ones manufactured manyyears ago. The stabilities of theelectrolyte and the purity of thealuminum used prevent them de-forming to lower voltage ratingswhen either idle or operating atlower voltages than the onesspecified on the original capacitor.

ELECTROSTATIC CAPACITORS

Electrostatic capacitors arevery different when we comparethem to electrolytic capacitors-not only in the way they are man-

ufactured, but in their circuit ap-plications. They are produced withclose tolerances generally around+ 10 percent, unless noted orspecified.

The most common dielectricemployed in the manufacturing ofelectrostatic capacitors include:impregnated paper, ceramic,mica, film and air.

Ceramic Capacitors

Ceramic is probably the mostversatile dielectric offeringunique characteristics. The mate-rial can be used proportionately indifferent methods to provide thevarious types of ceramiccapacitors.

Their physical styles are almostas varied as their electricalcharacteristics, which include thepopular disc, Fig. 3, tubular axiallead, Fig. 4, and extend into themore sophisticated, Fig. 5, trim-mer (variable and feedthroughtypes). The disc and tubular stylesare the most common in theirsimplist forms. They consist of acircular disc or a hollow tube ofceramic dielectric with metal elec-trodes applied to their opposingfaces. Wire terminals are con-nected to the electrodes and thebody of the capacitor is coveredwith insulating material. Becausethey employ ceramic as a dielec-tric and their comparativesimplicity, they are generally verylow in cost, but they are very reli-able.

There are four types of ceramiccapacitors, general-purpose, tem-perature -compensating, tempera-ture -stable, and frequency stable.

FILTERING

COUPLING

BYPASS

ENERGY

STORAGE

TUNING

TEMP.COMP.

General -Purpose: The construc-tion of this capacitor is common toother disc ceramics. It can beemployed as substitutes for mica,paper, or polyester types in filter,bypass, or coupling capacitors innon -critical circuits. A generalpurpose miniature monolithiccapacitor with epoxy coating isshown in Fig. 6.

Temperature -Compensating:These capacitors have a widerange of available temperature-co-efficients. The P types capaci-tors have a positive temperaturechange while the N type have anegative change. The NPO typehas practically no capacitancechange from - 25 degrees C to 85degrees C.

The prefix letter P on a capaci-tor means that above + 25 degreesC, the capacitance will increasewith the temperature (or a posi-tive co -efficient); N means thecapacitance will decrease (nega-tive co -efficient); and the lettersNPO designates no change exceptwith the NPO type which does nothave a number.

If we find a designation of P100,

Fig. 5-The trimmer (variable) and the feedthrougt ceramic capacitors are the more sophisticated types.

ilrAIR CERAMIC MICA PAPER

PLASTICFILM

ALUM.ELECT

TANTELECT

Vi/

VPRIMARY APPLICATIONS OF CAPACITORS IN HOME ENTERTAINMENT PRODUCT


it signifies that for every degreecentigrade of temperature in-crease (between + 25 degrees Cand +85 degrees C), the capaci-tance will increase 100 parts permillion. A capacitor with an N750rating provides a decrease of 750parts per million per degree in-crease, and an N1400 will providealmost twice the amount.

Temperature -Stable: The tem-perature stable capacitor is quitesimilar to the NPO type with somerefinements. Its temperaturerange has been increased so thatfrom - 60 degrees C to + 100 de-grees C, the capacitance changesonly + 7.5 percent from the statedvalue at + 25 degrees C.

Frequently -Stable: The capaci-tors are constructed so that theywill maintain a relatively con-stant resonant frequency overtheir operating temperaturerange.

The tolerance of ceramiccapacitors will be rated in guaran-teed minimum value (GMV) or inpercent. The GMV rating is themanufacturer's guarantee thatthe capacitor will not have less

capacitance than stated at 25 de-grees C.

Mica Capacitors

A few dipped -mica capacitorsare used in consumer electronicproducts and are very reliable.They are identified by ink stamp-ing, manufacturer's name or sym-bol, minimum capacitance inpicofarads, tolerance in percentand the DCW. They can be ob-tained with one percent toleranceor better.

The mica capacitor has a highdegree of stability over a largerange of operating temperaturesand quite often employed whereradio frequencies are encoun-tered.

Many ceramic capacitors can bedirectly replaced with dipped -mica types providing better per-formance and dependability. Thisreplacement does not apply totemperature compensating appli-cations.

Plastic -Film Capacitors

Polyester -Film: Those capaci-tors (Fig. 7), are used quite exten-

Fig. 8-General purpose ceramic capacitors with an epoxy coating for environment protection.

Fig. 7-Plastic-Film capacitor. Fig. 8-Polystyrene film capacitor.

sively in home entertainmentproducts and solid-state transis-torized circuitry has expandedtheir use.

The advantages of these capaci-tors are: they are very dense; theycan be produced into very thinsheets which are fairly stable asfar as their physical size; and theyhave a high dielectric strengthalong with good insulation resis-tance.

The construction of the polyes-ter -film capacitor is similar to thatof a paper type. The impregnatingoils are not used because thedielectric qualities are dependenton the film itself.

The most popular types are thedipped, molded, and wrap -and -fillstyles which are all extended -foilconstruction with less inductance.

Polystyrene -Film Capacitors:These capacitors, shown in Fig. 8,offer good stability in a smallpackage. Its insulation resistanceis very high in comparison to all ofthe other commonly used capaci-tors. Aging has practically no ef-fect on its capacitance value andthey have a slightly negativetemperature -coefficient.

The disadvantage of thiscapacitor is that its upper temper-ature range is only approximately+ 85 degrees C.

Rules For ReplacingElectrostatic Capacitors

Dipped paper Mylar capaci-tors can generally be used to re-place film, paper and combinationpaper -film capacitors.

Dipped epoxy capacitors willreplace wrapped, molded or pottedconstruction types.

Mica capacitors can be substi-tuted for ceramic capacitors wheretemperature compensation is notcritical.

Capacitors with higher volt-age ratings can be used, except infrequency sensitive circuits.

DC rated capacitors should bedecreased when used for AC appli-cations.

The capacitor value is de-creased if its operating tempera-ture is exceeded.

Power capacitors are usuallyrated at AC voltage and in mostcases can not be replaced with DCcapacitors.

JULY 1975 ELECTRONIC TECHNICIAN/DEALER / 15

An Extraordinary Offerto introduce you to the benefits of Membership in

ELECTRONICS BOOK CLUBfor a limited time only you can obtain

THIS forGIANT348 -Page Color TV Trouble Factbook only 49 rzt:.

MEMBER-SHIP

May we send you this helpful newbook as described on the facing

page as part of an unusual offer of aTrial Membership in Electronics BookClub?

This is a quality hardbound volume,especially designed to help you in-crease your know-how, earning power,and enjoyment of electronics.

This handsome, hardbound bookis indicative of the many other fineofferings made to Members . . . impor-tant books to read and keep . . . vol-umes with your specialized interests inmind.

Whatever your interest in electron-ics -radio and TV servicing, audio andhi-fi, industrial electronics, communi-cations, engineering -you will findElectronics Book Club will help you.

With the Club providing you withtop quality books, you may broadenyour knowledge and skills to buildyour income and increase your under-standing of electronics, too.

How You Profit from Club MembershipThis special offer is just a sample of

the help and generous savings theClub offers you. For here is a Club de-voted exclusively to seeking out onlythose titles of direct interest to you.Membership in the Club offers youseveral advantages.1. Charter Bonus: Take "COLOR TVTROUBLE FACTBOOK" . . . publish-er's list price $8.95 . . . for only 49c'with your Trial Membership.2. Guaranteed Savings: The Clubguarantees to save you 15% to 75%on all books offered. All books are of-fered at low Member prices (plus asmall shipping charge).3. Continuing Bonus: If you continueafter this trial Membership, you willearn a Dividend Certificate for everybook you purchase. Three Certificates,plus payment of the nominal sum of$1.99, will entitle you to a valuableBook Dividend which you may choosefrom a special list provided members.4. Wide Selection: Members are an-nually offered over 50 authoritative,new books on all phases of electronics.

5. Bonus Books: If you continue inthe Club after fulfilling your TrialMembership, you will receive a BonusDividend Certificate with each addi-tional Club Selection you purchase.For the small charge of only $1.99,plus three (3) Certificates, you mayselect a book of your choice from aspecial list of quality books periodical-ly sent to Members.6. Prevents You from Missing NewBooks: The Club's FREE News givesyou advance notice of important newbooks . . . books vital to your con-tinued advancement.

This extraordinary offer is intendedto prove to you, through your own ex-perience, that these very real advan-tages can be yours . . . that it is pos-sible to keep up with the literaturepublished in your areas of interest ...and to save substantially while so do-ing.

How the Club WorksForthcoming selections are described

in the FREE Club News, publishedthirteen times a year. Thus, you areamong the first to know about, and toown if you desire, significant newbooks. You choose only the main oralternate selection you want (or ad-vise if you wish no book at all) bymeans of a handy form and returnenvelope enclosed with the News. Aspart of your Trial Membership, youneed purchase as few as four booksduring the coming 12 months. Youwould probably buy at least this manyanyway . . . without the substantialsavings offered through Club Member-ship.

Limited Time Offer!Here, then, is an interesting oppor-

tunity to enroll on a trial basis . . . toprove to yourself, in a short time, theadvantages of belonging to Electron-ics Book Club. We urge you, if thisunique offer is appealing, to actpromptly, for we've reserved only alimited number of books for new Mem-bers.

To start your Membership on theseattractive terms, simply fill out and

mail the postage -paid airmail card to-day. You will receive "COLOR TVTROUBLE FACTBOOK" for 10 -dayinspection.SEND NO MONEY! If you are notdelighted, return it within 10 daysand your Trial Membership will becancelled without cost or obligation.Electronics Book Club, Blue RidgeSummit, Pa. 17214.

Typical Savings Offered ClubMembers on Recent Selections

International Transistor SelectorList Price $7.95; Club Price $4.95

Complete Auto Electric HandbookList Price $8.95; Club Price $5.95

Se-vic. Cassette/Cartridge Tape PlayersList Price $9.95; Club Price $6.95

Stroll Appliance Repair Guide -Vol. 2List Price $7.95; Club Price $4.95

Logical Color TV TroubleshootingList Price $8.95; Club Price $5.95

How to Repair Small Gasoline EnginesList Price $8.95; Club Price $5.95

TV Tuner Schematic/Servicing ManualList Price $9.95; Club Price $6.95

Basic Digital ElectronicsList Price $7.95; Club Price $4.95

Practical Test instruments You Can BuildList Price $7.95; Club Price $4.95

Th. Complete FM 2 -Way Radio HandbookList Price $9.95; Club Price $6.95

How to Trbshoot./Rep. Elect. Test Equip.List Price $9.95; Club Price $6.95

RCA Color TY Service Manual -Vol. 3 & 4List Price $17.90; Club Price $8.95

Electronic Experimenter's GuidebookList Price $7.95; Club Price $4.95

introduction to Medical ElectronicsList Price $9.95; Club Price $6.95

Basic Digital ElectronicsList Price $7.95; Club Price $4.95

Auto Stereo Service & installationList Price $8.95; Club Price $5.95

The Home Appliance ClinicList Price $7.95; Club Price $4.95

Directional Broadcast AnList Price $12.95; Club Price $7.95

Effsc. Troubleshooting with EVM & ScopeList Price $8.95; Club Price $5.95

Modern Communications Switching Sy.List Price $17.95; Club Price 513.95

Prac. Gd. to MATV/CCTV Sys. Des. & Sor.List Price $9.95; Club Price $5.95

Prec. Circuit Design for the ExperimenterList Price $8.95; Club Price $4.95

Installing TV & FM AnList Price $7.95; Club Price $3.95

Commercial FCC Li HandbookList Price $9.95; Club Price $5.95

Sears Color TV Service ManualList Price $8.95; Club Price $5.95

SEND NO MONEY! Simply fill in and mail postage -paid Airmail card today!

O70

07--,

-- D

.

CD

7C

D-4

-0.

4al

a_3

3-ft,

CD

3--.-

0n -4

-v.

M-4

-0

0o

(.1

-0a

-0

.-,

D.

-4-

n.

a,v,

D0.

,-4

-C

O-4

--

0V

'a'

0C

CA

--i-

v`o

C-4

- 0

-C

UC

-.a

CD

-- <

C

- O

DU <

Lol

0-

0v,

0 C

ELE

CT

RO

NIC

S B

OO

K C

LUB

Blu

e R

idge

Sum

mit,

Pa.

172

14Pl

ease

ope

n m

y T

rial

Mem

bers

hip

in th

e E

lect

roni

cs B

ook

Clu

b an

d se

nd m

em

y ow

n pe

rson

al, h

ardb

ound

cop

y of

"COLOR TV TROUBLE FACTBOOK-

Prob

lem

s &

Sol

utio

ns"

(bill

ing

me

only

49C

plu

s a

smal

l shi

ppin

g ch

arge

). I

fno

t del

ight

ed, I

may

ret

urn

the

book

with

in 1

0 da

ys a

nd o

we

noth

ing.

Eve

ryfo

ur w

eeks

you

will

sen

d m

e th

e C

lub

New

s, d

escr

ibin

g cu

rren

t off

erin

gs. I

fI

wan

t the

sel

ectio

n, I

do

noth

ing;

it w

ill b

e se

nt to

me

auto

mat

ical

ly. I

fI

dono

t wis

h to

rec

eive

the

sele

ctio

n, o

r if

I w

ant t

o or

der

one

of th

e m

any

alte

r-na

tes

offe

red,

I si

mpl

y gi

ve in

stru

ctio

ns o

n th

e re

ply

form

pro

vide

d, a

nd r

e-tu

rn it

to y

ou b

y th

e da

te s

peci

fied

. Thi

s da

te a

llow

s m

e at

leas

t 10

days

inw

hich

to r

etur

n th

e fo

rm. I

t, be

caus

e of

late

mai

l del

iver

y of

the

Clu

b N

ews,

I do

not

hav

e 10

day

s to

mak

e a

deci

sion

, and

so

rece

ive

an u

nwan

ted

sele

ctio

n,I

may

ret

urn

it at

you

r ex

pens

e. O

ther

wis

e, to

com

plet

e m

y T

rial

Mem

bers

hip,

I ag

ree

to p

urch

ase

at le

ast f

our

addi

tiona

l sel

ectio

ns o

r al

tern

ates

dur

ing

the

next

12

mon

ths.

I h

ave

the

righ

t to

canc

el m

y m

embe

rshi

p an

ytim

e af

ter

pur-

chas

ing

thes

e fo

ur b

ooks

.

Nam

eMN

Ni.

Add

ress

(NO

TE

: che

ck if

Q H

orns

or

n B

usin

ess

addr

ess)

City

Sta

teZ

ip

Com

pany

Titl

e1.

15(T

he C

lub

assu

mes

pos

tage

on

all p

repa

id o

rder

s. F

orei

gn a

nd C

anad

ian

pric

es 1

0°. h

ighe

r.)

A P AI r AI AV

f

Club Membership Advantages

Charter Bonus: Take "COLOR TV TROUBLE FACT -

BOOK" ... publisher's list price $8.95 ... for only49C with your Trial Membership.

Continuing Savings: The Club guarantees to saveyou at least 25% to 75% on the books you need.All books are offered at low Member prices (plus asmall shipping charge).

Wide Selection: Members are annually offeredover 50 of the new and authoritative books on allphases of electronic servicing.

Editorial Advisory Service: The Club's EditorialAdvisory Board selects only the important books ofdirect interest to you.

Bonus Books: If you continue in the Club afterfulfilling your Trial Membership, you will receive aBonus Dividend Certificate with each additionalClub Selection you purchase. For the small chargeof only $1.99, plus three (3) Certificates, you mayselect a jook of your choice from a special list ofquality books periodically sent to Members.

Prevents You From Missing New Books:The Club's FREE "News" provides advance noticeof new books vital to your continued professionaladvancement.

Fill In Other Side and Mail Today!

COLOR TVontcotou0LE TROUBLETROOK

fr519'' FACTBOOKBY theEAA°rs

348 pages 402 illustrations

Handsome, hardbound volume

Partial List of ContentsAdmiral-Chassis 11A9N; G11; G13; H10;

H12; 4H12; 14H12; K10; 4K10; K15;K16; 1(17; K18; K19; K20; 12K20; M20;S3776AN.

Canadian General Electric-Chassis M663;M678; M679.

Dumont-Chassis 120957; 958

Emerson-Chassis K17; K18; K20; M20.

General Electric-Chassis CB; CD; C1;C2; G1; H; HE; HI; H3; JA; KC; KC-KD; KE; LB; LI; L2; MA; N1; N2; P; U1.

May -Chassis T38; T904 & 45; T911;T918; T919; 1920; T924; T931; 1933;T935; T936; 1938; 1939; 1940; 1946;1947; T950; 1951; 1952; T956; 1957;7958; 7962; 1962-10; 1974; 1979; 1989.

MGA-Chassis T50.

Motorola-Chassis 16; 1921; TS908; 7S-914; TS915; 15918; TS924; 15929; 18;TS929; TS931; 15934; 15938.

Olympic-Chassis CT400; CT910; CT911,CTC19; CTC20; CTC21; CTC30; CTC31.

Philco-Chassis 16M91; 0185.

Philco-Ford-Chassis 3CS90; 3CS91; 3CY-90; 3CY91; 20KT40; 201741, 14M91,15M91; 16M91; 17MT80A; 18M170,16N182, 160185; 180185; 180186,2007; 200188.

RCA-Chassis CTC17; CTC17X; CTC20,CTC21; CTC22; CTC30; CTC36; CTC38;CTC39; CTC40; CTC41; CTC42; CTC43;CTC44; CTC46; CTC47; CTC48; CTC49;CTC50; CTC51; CTC52; CTC54; CTC55,CTC59; CTC63; XL -100.

Sylvania-Chassis 001; D02; D06; D07,D08; 010; D12; D12-09-09; 012-11-06,012-15-07; 012-20-50; 012-21-50; D14;D15; D16; E02-1, 2.

Truetone-Chassis 2DC4815.

Westinghouse-Chassis V2655; V2656; V-8001

Zenith-Chassis 12A13C52; 14A9C51; 19-DCI 2; 19DC22; 19DC28; 25DC57; 20X138.

Problems & Solutions

The most comprehensive single "all -makes"guide to color TV troubles and solutions everpublished . . . NEW, completely revised andenlarged 2nd Edition!

Twice the size of the bestsellingoriginal, this newly updated edi-

tion is a fully indexed all -in -one refer-ence guide to color -set troubles andrecommended solutions, manufactur-ers' service notes, and productionchange data-all alpha -numericallyarranged by manufacturer and model.This low-cost handbook contains ser-vice tips, troubleshooting data, andspecial problem -solving aids for allthe more popular U.S. and Canadiancolor TV makes and models, from A( Admiral) to Z (Zenith).

But that's not all! Included also aredetails concerning repetitive troubles,field -factory changes, new and unusualcircuits and descriptions of how theywork, special adjustment proceduresand other such pertinent service infor-mation. Of particular importance arethe manufacturer's production changes-this book includes a detailed ac-counting of such changes where theymight logically affect set performanceand where the technician might re-place a "factory" component with anunsuitable substitute.

This book should be considered a"must" for every practicing profes-sional TV service specialist . . . the in-formation it contains may easily saveyou hours of time repairing a "tough -dog" color TV. Partial schematics, lo-cation diagrams, chassis layouts, andsketches are included as necessary tomake every entry easy to understandand simple to implement in the field.To our knowledge, no other single vol-ume contains so much easy -to -find in-formation about so many individualmodels and brands of color receivers.A complete cross-reference index isprovided to enable you to quickly findthe specific material you need. In all,over 600 specific items are included.

The material provides instant solu-tions to many color TV circuit trou-bles, enabling you to diagnose and re-pair hundreds of otherwise difficult -to -solve problems. If you service colorTVs, this organized file of data willpay for itself time and again. 348 pps.,hundreds of schematics and diagrams.Hardbound. Publisher's list price $8.95.

literally hundreds of complete and partial schematics and illustrations makeeach of the over 600 entries in "Color TV Trouble Factbook" easy to understand.

AM EXTRAORDINARY OFFER...for more details circle 107 on Reader Service Card

"Exotic" Semiconductors-Theory & Testing

By Bernard B. Daien, ETD Contributing Editor

How UJTs, PUTs, Diacs and Triacs functionand how to test them and SCRs

The unijunction transistor(UJT) is an interesting devicewhich can be used in silicon -controlled rectifier (SCR) firingcircuits, timers, waveformgenerators, and a number of otherapplications. It has been aroundfor a long time, but, until lately, itcosts a bit more than most enter-tainment equipment manufactur-ers cared to spend. As a result, itsuse generally was confined to in-dustrial controls and military ap-plications.

Recently, however, the PUT(programable uninjunction tran-sistor) was developed. It offers thesame level of performance as aconventional unijunction transis-tor, but at a much lower cost. ThePUT is almost identical in appli-cation and function, but is quitedifferent in construction.

Fig. 1 illustrates the basic in-ternal construction of a UJT. Asingle crystal bar of N type mate-rial has an electrical connectionmade to each end. Somewhere be-tween the ends a "tap" is made inthe form of an electrical connec-tion to some P type material. This

forms a PN junction, the same as adiode. Because the UJT only has asingle junction, it is called a uni-junction transistor. The bottom ofthe bar is labeled Base 1, the topBase 2, and the tap is the Emitter.

Fig. 2 shows the schematic sym-bol for a UJT with the terminalsidentified.

Fig. 3 illustrates how the UJTfunctions. When a source of volt-age is impressed across the bar,current flows through the bar as itwould through any resistance. Be-cause the emitter is tapped intothe bar in a manner similar to thetap point on a tapped resistor, wecan show this schematically bymeans of imagined resistors R2and RI . And because the emitter istapped into the bar via some Ptype material which forms a PNjunction, the resultant junction isrepresented in Fig. 3 by diode D1.

If we assume that the tap wasmade at the center of the bar, then+ 5 volts would appear at the tap,as shown. If we now apply lessthan + 5 volts to the emitter con-nection, diode D1 will be reversebiased, and no current will flow

BASE 2

EMITTER

P TYPEMATERIAL

SINGLE CRYSTALBAR OF N TYPE

MATERIAL

BASE 1

Fig. 1-Physical design of a UJT.

BASE 2

EMITTER jBASE 1

Fig. 2-Schematic symbol of a UJT.

into the emitter. If more than +5volts is applied to the emitter,diode Dl becomes forward biased,and emitter current flows fromBase 1 through Dl to the emitterconnection. Once current flowsfrom base to emitter, the emitterinput resistance decreases and,consequently, the voltage acrossthe emitter -base junction de-creases because of the loweredinput resistance. Despite this de-crease in voltage, the emitter cur-rent remains heavy because thejunction is forward biased. The in-jection of emitter current releasesstill more current as a result ofsemiconductor action.

The combination of a decreasingvoltage and an increasing currentis indicative of what is called anegative resistance, which is theprincipal operating characteristicof the UJT. The emitter of the UJTexhibits negative resistance,which can be used for many appli-cations, as explained later.

Fig. 4 shows the negative resis-tance of the UJT in graphic form.When the emitter is below the"peak point," very little emitter


BASE 2

EMITTER +5V

041-D

foy

jRi

BASE 1

1o11

Fig. 3-Functional diagram which illustrates theoperating theory of a UJT.

CI PEAK POINT, (VP)1-_10

VALLEY, (Vv)cc

H21111

0 EMITTERCURRENT

Fig. 4-Graph which illustrates the negative resistance characteristic of the emitter of a UJT.

current flows because the emitteris reverse biased. When the "peakpoint" is passed, the emitter be-comes forward biased, and simul-taneously the emitter current in-creases while the emitter voltagefalls to the "valley" level.

Now, let's look at an illustrativeUJT circuit and its typicalwaveforms. The circuit in Fig. 5 isa UJT relaxation oscillator. Whenvoltage is first applied to the cir-cuit, capacitor C charges towardsthe emitter peak point (VP). WhenVP is reached the emitter becomesforward biased, discharging thecapacitor to the valley voltage (Vv)level. As the cycle repeats itself, asawtooth waveform is created atthe emitter (providing that charg-ing resistor R1 is reasonablylarge). If the value of R1 shoulddecrease to under 10,000 or soohms, the emitter might stay

+ 20V

cn

0

VP

IVV

71/10 EMITTER

cT

Fig. 5-UJT-equipped re'axation oscillatur.

0

-

BASE 2

cn

0

BASE 1

latched on. This is an importantpoint to remember, because thefrequency of oscillation is deter-mined by the values of R1 and Cand a constant determined by thetype of UJT. An attempt to in-crease the frequency of oscillationby reducing R1 to a very smallvalue will stop oscillations.

The waveform at Base 1 in Fig. 5is a positive -going, sharply peakedpulse. The waveform at Base 2 is anegative -going pulse. From this itcan be seen that the UJT can pro-vide several different types ofwaveforms with few externalcomponents. Typically, it is oper-ated as a pulse and nonlinearwaveform generator, and not as alinear amplifier like a bipolartransistor.

The emitter pulse waveform inFig. 5 is frequently used (viacapacitor or transformer coupling)for SCR firing purposes because ithas the fast rise time and suffi-cient energy (capacitor discharge)required to insure efficient SCRtriggering.

TESTING UJTS

The circuit in Fig. 5 can be usedas a simple UJT good/bad tester.Use a .05-mfd capacitor, a33,000 -ohm resistor (for R1), and47 -ohm resistors for the base re-sistors. A 9 -volt transistor batterywill suffice for a power source. Asmall 16 -ohm speaker placed

across the Base 1 resistor will au-dibly indicate oscillation if theUJT is operating normally.

In -circuit testing of UJTs can bedifficult, because the narrowpulses used in many circuits arenot readily visible on most servicetype scopes, and DC tests per-formed with multimeters do notindicate the presence of suchpulses at all. Further, since theUJT only has one junction, as pre-viously discussed, attempts toevaluate its condition by themethods used to check a bipolartransistor (forward and reverseresistances of both junctions) arenot applicable. It is recommendedthat the out -of -circuit oscillationtest be used.

THE NEED FOR PUTS

Before we can go futher, a newterm, Intrinsic Standoff Ratio,must be defined. Despite the for-midable name, it is quite simple. Ifyou look again at Fig. 3, it is obvi-ous that if the emitter "tap point"is placed higher or lower on thebar, the peak firing point will bechanged accordingly. The higherthe tap on the bar, the more volt-age it takes before the peak pointis reached.

Since we are dealing with avoltage divider, the peak point isalways a fraction of the totalapplied voltage, and the fraction isdetermined by tap location. The


symbol for this fraction is "n" theGreek letter similar to a lowercase letter "n." This is the IntrinsicStandoff Ratio, and is used as fol-lows: Assume we have applied 20volts to a UJT with a standoffratioof 0.5. The emitter peak point willfire at 0.5 times the applied volt-age, or 0.5 times 20 volts = 10volts VP. So you see that the stand-off ratio merely describes wherethe tap is on the bar, and in thiscase it was at the 50 -percent point.The standoff ratios of most UJTsrun between 0.5 and 0.9, princi-pally because of factors related tothe design and fabrication of thedevice.

As you can see, the standoffratio is fixed. The actual standoffratio usually is slightly differentthan the published value becauseof the forward junction voltagedrop. (The emitter is a junctionsimilar to a diode.) If you shouldneed a UJT with a different stand-off ratio, you have to buy one, andas with all components, there aretolerances. If you need a "tight"tolerance, you are in for a job ofselecting one out of many by test-ing each one. To overcome thisproblem, a new device has beendeveloped. It is called a Program-mable Unijunction Transistor(PUT).

PUTS AND SIMILAR DEVICES

To better understand the PUT,we will first examine its basicstructure, which also is common toSCRs, Triacs, Diacs, and many

other "snap action" devices. Fig. 6illustrates the derivation andbasic structure of such devices.

Fig. 6A shows a PNP and anNPN transistor connected to forma "latching" circuit. When voltageis applied to the anode and cathodeterminals, no current flows be-cause both transistors are in the"off" state. If, however, one of thetransistors can be made to turn on,it will, in turn, forward bias theother transistor. (The collector ofeach transistor is tied to the baseof the other transistor.)

Once turned on, the circuit inFig. 6A will stay latched on be-cause each transistor continues tosupply base drive to the other. Thecircuit can be turned on intention-ally three ways, and inadvertentlyone other way. If the terminallabeled "anode gate" is suppliedwith even a momentary pulse thatis negative with regard to theanode, the PNP transistor willturn on, initiating latchup. If the"cathode gate" is made evenmomentarily positive with respectto the cathode, the NPN transistorwill turn on, with the same result.And, if the voltage between anodeand cathode is increased beyondthe voltage rating of the devices,"break over" occurs, causing turnon and latchup.

It is possible to cause undesiredturn -on of the circuit in Fig. 6A byapplying voltage at such a rapidrate that the steep wavefrontreaches the gate via the junctioncapacitances. This also can hap-

CATHODEGATE 0-

A+ ANODE"

ANODEGATE

"CATHODE'

B

ANODE

CATHODEGATE

CATHODE

ANODEGATE

C

ANODE

ANODEGATE

CATHODEGATE

CATHODE

Fig. 6-Illustration which reveals the basic structure (A) of a lour -layer semiconductor device and the"evolution" of the basic structure into a device with two separated but interconnected transistors (B)and. finally. into a practical four -layer device (C) which, with minor variations in construction. isuseful as an SCR, a PUT and a Diac.

pen due to transients. (Remember,it takes only a short durationpulse to cause turn -on.) To preventthis unwanted turn -on, small ex-ternal capacitors, resistors or in-ductances often are used as low-pass filter elements.

Fig. 6B shows the PNP andNPN internal transistor struc-tures, along with the wiring inter-connections and terminals. Noticethat the N segments are tied to-gether, as are the P segments.

In Fig. 6C the two separatestructures have been consolidatedinto one, eliminating the inter-connections. This is the basic fourlayer semiconductor device whichcan be used in many ways. Slightdifferences in fabrication are usedto optimize performance for par-ticular uses. For example: An SCR (silicon controlled recti-fier) omits the anode gate lead,and thus is fired only by a pulsethat is positive with respect to thecathode. The PUT omits the cathode gatelead, and is fired by a voltage thatis negative with respect to theanode. The DAC omits both gate leads,and is fired by break -over causedby excessive applied voltage. (Thisdevice also is called a bilateralswitch, and in some versions ismade of only 3 layers.) The Triac is a somewhat morecomplex device. It can be consi-dered to be two SCRs in parallelbut with reverse connections (eachanode connected to the othercathode). This "composite SCR"can be turned on by voltage ofeither polarity, whereas an SCRcan be turned on only when theanode is positive. The one gate ofthe Traic turns on the device whenit is driven by a voltage of thesame polarity as the anode termi-nal. For example, when the anodevoltage is positive, the Traic turnson if a positive voltage also isapplied to the gate. When theanode is negative, application of anegative voltage to the gate willturn on the device.

TESTING SCRS AND TRIACS

All variations of four -layerdiodes are non linear devices,which means that they generatepulses or other waveforms whose

22 ELECTRONIC TECHNICIAN DEALER, JULY 1975

smlommos up

Back by popular demand, GE Tube presents the 1975 version of BOTTOMSUP. It's your chance to cash in on a great gift bonanza, from now throughNovember 30.Start saving those familiar gray flaps (with the GE monogram) from thebottom of GE tube cartons. Also save the red or blue warranty serialnumber stickers (with GE monogram) from GE ULTRACOLOR andSpectrabrite color picture tubes. (One of these stickers is worth20 gray receiving tube flaps. 75 flaps equal one book of S & HGreen Stamps.)Your authorized GE Tube distributor has all the details in a colorfulcatalog crammed full of the gifts you want. He's waiting for you tocome in and pick up your copy.Your current inventory counts, so start saving now-and keep buyingGE replacements to boost your total points. Get the details fromyour authorized distributor; he'll show you how to tear the bottomoff GE!

BOTTOMS AnJULY 1975, ELECTRONIC TECHNICIAN/DEALER / 23

shapes are unrelated to the inputvoltage waveform. Generally,SCRs and Triacs are used aspower -switching devices at fre-quencies up to 100 KHz, whileUJTs, Diacs and four -layer diodesare used in the same frequencyrange to drive power switches andperform other functions (exceptlinear amplification).

Because four -layer devices donot amplify in a conventionallinear manner, they are difficultto test with the usual methodsused for linear devices. In mostcases, such tests are meaningless.There are, however, some simplein -circuit tests that can be per-formed on SCRs and Traics(power -switching devices) withcommon TV test equipment. Thekey to such testing lies in the factthat four -layer devices "latch up"(conduct) when certain conditionsexist, and stay latched until thecurrent through them drops tozero for a period of time sufficientto enable the device to turn off.The current can be made to drop tozero by placing a reverse bias onthe device, by interrupting (open-ing) the circuit with another de-vice or component. What we arelooking for is one of the followingconditions: A) A shorted device,B) an open device, C) a device thatdoes not respond to the normal"turn on" signal, or D) a devicethat does not turn off with a nor-mal "turn off" condition.

Testing The SCR

Like an ordinary rectifier, theSCR never conducts when it is re-verse biased. Unlike a rectifier,the SCR conducts in its forwarddirection only if its gate is drivenpositive with respect to its cathodefor a certain minimum period oftime (turn -on time interval).

The following checklist shouldmake SCR troubleshooting easierfor you:

1) Does the SCR stay on all thetime?

a) If yes, does the voltageacross the SCR go to zero (or re-verse bias) for several mic-roseconds for a "fast switching"type SCR, or for ten times thatlong for a standard -speed SCR?

b) If yes, you should also de-

termine if the gate drive is everabsent.

c) If gate drive is absent, andvoltage across the SCR goes to zerofor the appropriate time, the de-vice must turn off if it is good.

2) Does the SCR stay off all thetime?

a) If yes, is proper gate drivesupplied during the interval theanode is forward biased? (Gatemust be positive with respect tocathode for the appropriate inter-val of time, to insure turn -on).

b) If the anode is positive andthe gate is driven with a propersignal, the SCR must turn on ifgood.

The preceding checklist as-sumes that you have made theusual check of anode supply volt-age before testing the device. Thegate drive can be checked only bydisconnecting the lead to the gateand examining the waveformamplitude and duration on ascope. The gate drive waveformcannot be analyzed with the gatein the circuit, since the gate/cathode forms a diode, whichclamps the waveform at theamplitude level of the diode for-ward drop. Once the SCR goes intoheavy conduction, the internalvoltage drop "masks" the applieddrive.

The preceding list also tells youwhat circuit defects to look for andwhat voltages will be present orabsent for each. Note, however,that you must use a little commonsense too. For example, the SCRshould remain on only if the gatedrive is present during the inter-val the anode is forward biased,(Gate drive during anode reversebias is ineffective, as SCRs onlyconduct when forward bias isapplied to the anode.) An SCRwhich conducts on the reversebiased half of an AC cycle isshorted.

Testing The Triac

Triacs can be triggered on whenthe anode is negative or positive,although the gate sensitivity var-ies from state to state. This tendsto make testing a little confusing.Things become a little clearer ifyou consider the Triac as a solid-state relay, replacing a magneticsingle -pole, single -throw relay. It

CURRENT

Vi Vs

.der"

.0- VOLTS0

VOLTS+ -

Vs V

Fig. 7-- -Voltage -vs current graph fnr a typicalDiac.

works on AC or DC of either polar-ity, just the way the magnetic (orreed) relay works, with one excep-tion: Magnetic relays stay acti-vated as long as the coil is ener-gized, and open only when the coilis deenergized, but the Triac stayslatched up even after the gatedrive is removed. Just as with anSCR, the voltage across the Triacmust go to zero long enough for theTriac to unlatch. Unlike an SCR,reverse bias won't turn off a Triacunder many circumstances, be-cause the Triac works with volt-ages of either polarity.

As with SCRs, when trouble-shooting Triacs you will be look-ing for a shorted or open device, orone which does not respond to thegate signals. If the Triac stays onall the time, disconnect the gatelead. If the Triac still stays on, it isdefective. If not, the gate drivesource is at fault.

If the Triac stays off all the time,disconnect the gate lead and checkfor the gate drive, which should beseveral volts for more than 25 mi-croseconds. If there is gate drive,the Triac is probably defective. Ifthere is no gate drive, the problemis in the gate drive or eariler sens-ing circuits.

Again, remember to check theanode supply voltage. Semicon-ductors, like vacuum tubes, do notfunction properly without the cor-rect voltage applied.

THE DIAC

Up to this time we have merelymentioned that these diodes areused frequently to fire SCRs andTraics, but there was no discus-sion as to why they are so popularin this application. Fig. 7 helps toillustrate why. It is a volts -versus -current curve for a typicalDiac.

Note that as the voltage acrossthe Diac is made more positive,

24 I ELECTRONIC TECHNICIAN/DEALER, JULY 1975

DIAC.

ACINPUT LOAD

Fig. 8-A representative Diac-equipped circuifor triggering an SCR or Triac.

very little current flows until theswitching voltage level, Vs, isreached. Then the device "snaps,"the current increases very rapidly(in microseconds), and the voltageacross the device falls to a lowvalue, termed the holding value,VH.

If the Diac is used in a circuitlike that in Fig. 8 (which alsoshows the symbol for a Diac), theoutput will consist of one pulse foreach half cycle of AC input. Thepulse is negative for a negativehalf cycle, and positive on the posi-tive half cycle. Operation is as fol-lows: The capacitor charges. Whenthe voltage across the capacitorreaches the Diac's switching volt-age, the Diac suddenly conducts,and the voltage drop across it de-creases. The capacitor then dis-charges into the load through thelow forward resistance of the Diac.Since the capacitor's dischargecurrent is limited primarily by theload resistance, a relatively largecurrent can flow through theDiac. This is very desirable forSCR and Triac firing because theirgates should be driven by a pulsewith fast rise time and relativelyhigh current and high voltage,thus insuring fast turn -on. Aslowly rising pulse would result inslow turn -on, causing high SCRdissipation and other undesirableeffects.

As illustrated in Fig. 7, the Diacworks equally well with positiveor negative voltage applied; con-sequently, it works in the samemanner on both the positive andnegative half cycles, which isnecessary when driving Triacs.(Remember, Triacs operate onboth halves of the AC input cycle.)

SCR, TRIAC AND DIAC SYMBOLS

Fig. 9 shows the schematic sym-bols for this family of devices,along with element labels.

ASCR

ANODE

BTRIAC

TERMINAL 2

GATE 7T GATE

CATHODE TERMINAL 1

CDIAC

A

Fig. 9-Schematic Symbols for an SCR (A).a Triac (B), and a Diac (C).

Fig. 9A is the SCR symbol withthe anode, cathode and gateclearly labeled.

Fig. 9B is a Triac, the gate ofwhich is easily identifiable, butthe other two terminals aremerely titled "Terminal 1" and"Terminal 2," since either can beconsidered to be an anode, or acathode, depending upon the di-rection of conduction.

Fig. 9C, a Diac, normally has noterminal labels at all, since it is asymmetrical device which func-tions equally well in either direc-tion.

GATE AND OUTPUT MEASUREMENTS

When troubleshooting semi-conductor switching devices, re-member that the triggering and/oroutput waveforms of such devicesmight be a half or a quarter cycleof a sine wave or might be a nar-row pulse, depending upon theparticular device and its applica-tion, and that conventionalservice -type meters cannot be re-lied upon to give meaningful indi-cations of such pulse -typewaveforms. A narrow pulse mightnot produce any type of meter in-dication at all, and low -duty -cyclewaveforms of, say, 100 voltsamplitude might produce lowreadings. Only peak -reading me-ters and oscilloscopes are accuratedevices for these nonlinearwaveforms. The peak meters atleast indicate what the peak valueof the wave is. A scope, the bestchoice of all, shows the wave -shape, duration and amplitude,providing it is a wide -band scopewith a stable triggering systemcapable of "catching" fast, narrowpulses. The newer service scopeswith a useful 10MHz bandwidththat is flat to 5 MHz are adequate.But if your scope is "3dB down at4.5 MHz," it actually reads 7 voltson a 10 -volt peak signal at 4.5

MHz if you calibrate it at a lowfrequency. A 30 percent error isthree times greater than accepta-ble, even for the "roughest" sort ofservice work. If your scope is rated"plus or minus 1 db" at 4.5 MHz, itis satisfactory for all but the mostcritical type of measurements youwill encounter in the servicing ofsemiconductor switching devices.

SELECTING REPLACEMENTS

All devices with a 1N-, or2N-number are registered andsupposed to conform to a uniformstandard, so they should be inter-changeable. Several manufactur-ers are now providing approval forsubstitutes provided by semicon-ductor firms, (among these areZenith), and that's a big help."House number" parts often canbe replaced by parts recommendedin service literature for theequipment prepared by indepen-dent major publishers. A good ruleis: "When in doubt, get an originalreplacement part." SCRs, Diacs,etc., are sorted out on a voltage/current/turn-on and turn-off timebasis. The average service shopsimply does not have the requiredtime and test equipment to gradeout devices for substition pur-poses.

During 1974-75, there has beena noticeable increase in the atten-tion semiconductor manufactur-ers have given to the replacementparts market. This is probably be-cause their OEM business has de-clined. In any event, the replace-ment and substitution manualsnow offer more items, are betterorganized, and are more accuratethan in the past, and, con-sequently, they are more useful.In general, the parts offered as"substitutes" are capable of with-standing more voltage and cur-rent than the original parts, andin the case of older types of de-vices, the newer versions offeredare superior in most other respectstoo. Despite this, if the part has astandard 1N-, 2N- or 3N-number, or some other commonlyencountered number, you usuallycan save real money by buyingit under that number instead ofthe "replacement part number"offered in crossreference litera-ture.

JULY 1975. ELECTRONIC TECHNICIAN DEALER 25

New capacityto 10,725 lbs. GVWNow you can consider compact Ford Par-cel Vans for jobs previously too big or tooheavy for this type of truck. New 14 -ft.body is 8 ft. wide, offers 40% more cubethan Ford's biggest '74 model. GVIV's to10,725 lbs. boost payloads, too. For easyloading, hinged rear doors are almostbody wide. Doors swing open all the wayagainst body sides...have slam -shutlatches, provision for locking. Options in-clude roll -up doors, cab partitions with orwithout walk-thru, roof vents, rub rails.

12 -ft. body has 138 in. wheelbaseIt's 7 ft. wide on E-250, 8 ft on E-350.

14 -ft. body has 158 in wheelbase.Body is 8 ft. wide, has 6'2" headroom..,

New driver roomand comfortFord gives the driver what he needs toget more done with less effort. Big, widecab doors make getting in and out easy.Because the engine is forward out of theway, driver can easily step back into theload area-or across to the curbside cabdoor. Both driver and helper have goodlegroom and footroom. Thick, insulatedengine cover has handy pockets on top.

New durabilityengineeringSeparate body with frame, the onlyAmerican van with this construction, pro-vides a strong foundation for the entirevehicle. Frame rails are designed to helpcushion impact from the front. To resistcorrosion, key components are galvanizedand the entire cab is primed by deep -dipElectrocoat. These vans are built to keeptheir value. Cruise-O-Matic, power frontdisc brakes, 300 Six are standard.

Energy -absorbing frame rails help cushion frimpact Frame is the first in any American war,

Standard and auxiliary fuel tanks are locatedbetween the frame rails, total up to 42.6 gallons


For '75, Ford redesigns theParcel Delivery Van.

New high -capacity Econolinesoffer bodies to 14 ft. long, over 40% more cube,

new efficiency for delivery operations.

Engines to match the job; choiceof 300 Six, 351 -cu. in. V-8, 460 -cu. in.V-8. All truck strengthened.

Forward engine locationpermits 17 outsideservice checks.

Improved Twin -I -Beam suspensionprovides front-end toughness andstable ride

Cruise-O-Matic Drive, powerfront disc brakes are standard;power steering optional.

Separate frame constructionfor strength, durability.

Engine and wheelhousingsmoved forward for more driverand passenger room. comfort

Offered with single rear (E-250)or dual rear wheels (E-350).

Econoline Vans: Four serieswith GVW's to 10,000 lbs.Virtually all of the advantages of Ford Parcel Vans, like strongbody -frame construction, apply to regular '75 Ford EconolineVans. You also get a greater choice of models and options tomatch your needs, new highs in weight capacity, 12 in. longercenter load length than last year, new 54 -in. wide rear doors,sliding or hinged side cargo doors. See your Ford Dealer now.

The closer you look, the better we look.

FORDECONOLINE VANS

FORD DIVISION

...for more details circle 133 on Reader Service CardJULY 1975. ELETRONIC TECHNICIAN/DEALER 27

Powers, Logs & dBs--A Brief Review By Jack Hobbs and J.W. Phipps

If you are like most of us, youprobably were "exposed" to powersof ten, logarithms and decibelcomputations a few years ago dur-ing the "math portion" of a formalelectronics course. And, unlessyou are one of the rare electronictechnicians who uses these areasof math on a daily or even weeklybasis, you, like most of us, proba-bly have gotten a little rusty. If so,the following brief review of thefundamentals of powers of ten,logarithms and decibels shouldhelp brush away some of themathematical cobwebs, so thatyou'll feel a little more comforta-ble when the occasional need formathematical computation arisesin your "practical" workadayworld of servicing electronics.

POWERS OF TEN

The principal reason for usingpowers of ten is to simplify themultiplication and division of thelarge whole numbers and/or largedecimal fractions which electronicmathematical computations in-evitably involve.

TABLE 1POWERS OF TEN

AND EQUIVALENTS

Power Equivalent Value TermAbbre-viation

10'2 1.000.000.000.000 Tera - T

10" 100.000,000,00010'0 10.000.000.000108 1.000.000.000 Giga-108 100.000.00010' 10.000.000108 1,000.000 Mega - M108 100.000104 10.000103 1.000 Kilo - K102 10010' 10

100 1

0.1 deci-10-810-8

0.01

0.001-centimilli-

m

10-8 0.000110-8 0.0000110-8 0.000001 micro-10-7 0.000000110-8 0.0000000110-8 0.000000001 nano-10-18 0.000000000110-11 0.0000000000110-12 0.000000000001 pico- p

Expression of a number in pow-ers of ten is merely a way of stat-ing how many times a smallernumber (and subsequent productsderived from it) have to be multi-plied by ten to equal it. For exam-ple, to equal 100, the number 1 hasto be multiplied twice by 10, or 1 x10 = 10 x 10 = 100. This samemathematical expression can beabbreviated to read: 100 = 1 x 102.

Similarly, to equal 1000, thenumber 1 must be multiplied by10 three times, or 1 x 10= 10x 10= 100 x 10 = 1000. And, likewise,this mathematical expression canbe abbreviated to read: 1000 = 1 x103.

To express any whole number asa smaller whole number and/ordecimal fraction, move the deci-mal point to the left as manyplaces (digits) as you deem neces-sary for convenient computationand then use the number of placesas the power of ten exponent. (Inthe expression 1000 = 1 x 103, thesmall 3 is the exponent, or power.)For example, to express thenumber 1361.5 as a smaller wholenumber, the decimal point ismoved three places to the left andthe "new" number is expressed as1.3615 x 103.

Decimal fractions, such as.4632, can be expressed as wholenumbers in the same manner ex-cept that the decimal point ismoved to the right and a negativesign is placed before the exponent.For example, .4632 can be ex-pressed as 4632 x 10-4.

Listed in Table 1 are the wholenumbers in multiples often from 1to 1 trillion and their equivalentvalues expressed as powers of ten.Also included are decimal frac-tions in multiples of ten from .1 to1 pico and their equivalent valuesexpressed in powers of ten.

As stated previously, the prin-cipal reason for using powers often is to make large whole num-bers and/or large decimal frac-tions easier to multiply and di-vide. Examples of these applica-tions of powers of ten are shown in

the computations in Table 2.

COMMON LOGARITHMS

The logarithm, like the power often, is a method of "re -phrasing"numerical quantities so that theycan be more easily multiplied anddivided. As with powers of ten,multiplication of logarithms is ac-complished by algebraic addition,and division is accomplished byalgebraic subtraction.

In the common system oflogarithms, the logarithm (ab-breviated "log") of a number is thepower, or exponent, to which thenumber 10 must be raised to equalthat number.

As you will recall from the pre-vious discussion of powers of ten,10 can be expressed as 100, 100 canbe expressed as 102, 1000 can beexpressed as 103, etc. Numbers be-tween even multiples of ten (forexample, those between 1 and 10,10 and 100, and 100 and 1000, etc.)are expressed as the same, or"original," group of digits (minusthe zeros which precede or followit) plus a power of ten exponent(such as 102) which tells how manytimes that number must be mul-tiplied by 10 to equal the "origi-nal" number. For example, 5600can be expressed in powers of tenas 56 x 102.

On the other hand, commonlogarithms convert an "original"numerical quantity into a com-pletely different, two-part numer-ical expression which tells howmany times 10 must be multipliedby itself to equal "the original"numerical quantity. In otherwords, the log of a number tellsyou to what power ten must beraised to equal that number.

The first segment of a log is awhole number called the charac-teristic. The characteristic of anumerical quantity equal to 1 orgreater is computed by countingthe number of digits to the left ofthe decimal point and then sub-tracting one. For example, thecharacteristic of 1560.8 is 3.

The characteristic of a numeri-cal quantity less than 1 is com-puted by counting the number ofdigits to the right of the decimalpoint and then adding a negativesign. For example, the charac-teristic of .0456 is -4.

The other segment of a

28 ELECTRONIC TECHNICIAN DEALER. JULY 1975

logarithm is a 4 -digit decimalfraction called the mantissa. Themantissa is obtained from a tableofcommon logarithms, a portion ofwhich is shown in Table 3. To findthe mantissa of a particular nu-merical quantity, locate in the "N"column of the log table the firsttwo -digits of the number. Thenproceed horizontally along thisline of numbers until you reachthe vertical column whose head-ing number corresponds to thethird digit of the number you areconverting to a log. The four -digitnumber in this column is the man-tissa. For example, the mantissa of1560.8 is found by searching downthe "N" column until you come to15, then proceed horizontally tothe vertical column with a head-ing of 6. The mantissa of 1560.8 is.1931. By combining the charac-teristic (3) and the mantissa(.1931) you arrive at the log of1560.8, which is 3.1931.

If the number you are convert-ing to a log has only one or twodigits, or if the third digit is a zero,always use the first, or "zero," ver-tical column. For example, to findthe mantissa of 2, 200 or 2000,proceed down the "N" column to 20and use the mantissa under the"N" vertical column, which is3010. The complete log of 2 is.3010, the complete log of 20 is1.3010, and the complete log of 200is 2.3010.

If the number you are convert-ing to a log has more than threedigits, you can find the fourth digitby referring to the 'proportionalparts" segment of the log table inTable 3. (Four -place logs are thehighest accuracy you will need formost electronic -related computa-tions, and three -place logs areusually adequate.) For example,to find the mantissa of 1543.6, find15 in the "N" column and thenmove horizontally to the "4" col-umn, which gives a "three -place"mantissa of .1875. Then proceedon the same horizontal line to the"3" column of the proportionalparts segment, which gives afourth -digit readout of .0008. Add-ing the .1875 and the .0008 pro-duces a mantissa of .1883, which isaccurate to four places. The com-plete log of 1543.6 is 3.1883.

The antilog of a log is merely the"original" number which was con-

verted to a log. An antilog is foundby first finding the log's mantissain the log table and then combin-ing the "N" column two -digitnumber and the single digit in theheading of the vertical column inwhich the mantissa appeared. Thedecimal point is then placed to theright a number of spaces equal tothe characteristic plus 1. (For logswith negative characteristics, thedecimal point is positioned to theleft a number of spaces equal to thecharacteristic.) For example, theantilog of log 3.3118 is 20 ("N" col-umn digits) and 5 (mantissa col-umn heading), producing 2050.

Examples of the applications ofcommon logarithms in electronicsare given in the following discus-sion of decibels.

DECIBELS

A ratio of 20 called the bel hasbeen used for years as the basis forcomputing and expressing manyelectronic measurements thatotherwise would be more difficultand less accurate. However, be-cause the bel, like the farad, forexample, is a large unit, the de-cibel (0.1 bel, abbreviated dB) isused for most practical applica-tions.

The dB is the logarithm of theratio of two powers, two voltagesor two currents. Or, we can saythat the dB is a unit of measure-ment of the ratio of two quantities.

The dB is used in measuring,computing and expressing powergain or loss, voltage gain or lossand current gain or loss. Specificapplications include checking fre-quency response variations inaudio amplifiers; measuring am-bient noise and other sound levels;and computing antenna gain overthat of a half -wave dipole or anisotropic.

One good reason for employingdB formulas, and thereforelogarithms, is to avoid multiply-ing and dividing complicated fig-ure groups. By using dBs, the pro-cess is frequently reduced to sim-ple algebraic addition and/or sub-traction. Logarithms minimizefiguring and reduce multiplica-tion and division to simple addi-tion and subtraction, respectively.

Why The Logarithmic Decibel

The human ear responds to dif-

ferent levels of sound in a non-linear manner. A given volume ofsound must be changed about 26percent before the ear perceives achange. But the ear won't notice asubsequent series of volume in-creases unless each increase in-cludes an additional 26 percentadded to each previous increase.In other words, the process mustproceed in an exponential manner.

For example, assume that an"average" human ear can detect areference sound level of 1mW,which we can arbitrarily call zerodB. This level would have to beincreased to 1.26mW (or about1dB) before the ear could detect achange. Then the volume wouldhave to be increased to about1.6mW (or to 2dB) before anotherchange is noticed. At the 17th in -

TABLE 2MULTIPLICATION &

DIVISION USINGPOWERS OF TEN

MULTIPLICATION.Rule-Add the exponents algebra-

icallyExample -50 microamps x 10K ohms.

50 x 10-6x 10 x 103

500 x 10-s - .5 volts

DIVISION:Rule-Algebraically subtract the ex-

ponent of the denominator from the ex-ponent of the numerator

Example -1000 volts divided by 25 Kohms,

1 x

25 x 103 1/25 .04 amps

SLUARING:Rule-Multiply the number by itself

and double the exponentExample -2000 volts squared divided

by 100 ohms,12 x 103)2 4 x 106 4 x 104

1 x 102 1 x 102 1

40 K watts

S]UARE ROOTS:

Rule-Extract the square root of thenumber and divide the exponent by 2

Example-The square root of (20 K ohmstimes 50 microfarads).

J20 K ohms x 50 microfarad -

N2 x 104 x 50-6 = 2 x 50 x 10-2

100x10-2= 10 x 10-1 = 1

JULY 1975. ELECTRONIC TECHNICIAN/DEALER / 29

TABLE 3

COMMON LOGARITHMSProportional Parts

N 0 1 2 3 4 5 6 7 8 9 2 3 4 5 7 8 910 0000 0043 0086 0128 1 0170 0212 0253 0294 0334 0374

,14 8 12 17 21 2 29 33 37

11 0414 0453 0492 0531 0569 0607 0645 0682 0719 0755 4 8 11 15 19 2 26 30 3412 0792 0828 0864 0899 0934 0969 1004 1038 1072 1106 3 7 10 14 17 2 24 28 3113 1139 1173 1206 1239 1271 1303 1335 1367 1399 1430 3 6 10 13 16 1 23 26 2914 1461 1492 1523 1553 1584 1614 1644 1673 1703 1732 3 6 9 12 15 1 21 24 27

15 1761 1790 1818 1847 1875 1903 1931 1959 1987 2014 3 6 8 11 14 1 20 22 2516 2041 2068 2095 2122 2148 2175 2201 2227 2253 2279 3 5 8 11 13 1 18 21 2417 2304 2330 2355 2380 2405 2430 2455 2480 2504 2529 2 5 7 10 12 1 17 20 2218 2553 2577 2601 2625 2648 2672 2695 2718 2742 2765 2 5 7 9 12 1 16 19 2119 2788 2810 2833 2856 2878 2900 2923 2945 2967 2989 2 4 7 9 11 1 16 18 20

20 3010 3032 3054 3075 3096 3118 3139 3160 3181 3201 2 4 6 8 11 1 15 17 1921 3222 3243 3263 3284 3304 3324 3345 3365 3385 3404 2 4 6 8 10 1 14 16 1822 3424 3444 3464 3483 3502 3522 3541 3560 3579 3598 2 4 6 8 10 1 14 15 1723 3617 3636 3655 3674 3692 3711 3729 3747 3766 3784 2 4 6 7 9 1 13 15 1724 3802 3820 3838 3856 3874 3892 3909 3927 3945 3962 2 4 5 7 9 1 12 14 16

25 3979 3997 4014 4031 4048 4065 4082 4099 4116 4133 2 3 5 7 9 1 12 14 1526 4150 4166 4183 4200 4216 4232 4249 4265 4281 4298 2 3 5 7 8 1 11 13 1527 4314 4330 4346 4362 4378 4393 4409 4425 4440 4456 2 3 5 6 8 11 13 1428 4472 4487 4502 4518 4533 4548 4564 4579 4594 4609 2 3 5 6 8 11 12 1429 4624 4639 4654 4669 4683 4698 4713 4728 4742 4757 1 3 4 6 7 10 12 13

30 4771 4786 4800 4814 4829 4843 4857 4871 4886 4900 1 3 4 6 7 10 11 1331 4914 4928 4942 4955 4969 4983 4997 5011 5024 5038 1 3 4 6 7 10 11 1232 5051 5065 5079 5092 5105 5119 5132 5145 5159 5172 1 3 4 5 7 9 11 1233 5185 5198 5211 5224 5237 5250 5263 5276 5289 5302 1 3 4 5 6 9 10 1234 5315 5328 5340 5353 5366 5378 5391 5403 5416 5428 1 3 4 5 6 9 10 11

crease of the original level wewould be at the 17dB or 50mWoutput level. At the 30th increase(or 30dB level) the power outputwould have soared 1,000 times-to the 1W level. Hence, the natureof the human ear, which respondslogarithmically, has established apractical system for measuringpower gains and losses.

Practical dB Formulas

Perhaps the most useful dBformula employed in our work,especially in audio, is that usedwith power and known as the dBmformula. In most electronic work,dBm is an arbitrary "referencesystem" in which zero dBm is1mW (1 milliwatt) of power de-veloped by 0.7746 volts across aresistance of 600 ohms. The stan-dard power dB formula is written:dB = 10 log P. This means simplythat dB equals 10 times thelogarithm of P2 divided by P1.

The best way to understand thedBm process is first to apply itsbasis to Ohm's power formula:

RE' 0.7746' o. x x 10. I.,600600 imwNext, assume that we have apreamp or amplifier that requires

a 1mW input to produce 2W out-put. We want to know the dBmgain of the amplifer. So, dBm = 10log = 10 log 2-",1(o-' = 10 log 27°= 10 x 3.3010 = +33dBm. If P2 isgreater than P1, a gain results andis expressed as + dBm. If P2 issmaller than P1, a loss results andis expressed as -dBm. Let's dou-ble the power output to 4W: 10 log14nwiw = log 4000 = 3.6021 x 10 = 36dBm. Note that by doubling thepower we increased the dBms by 3.This 3dB increase is one basiccharacteristic that should be re-membered about doubling power.

If power is increased 10 times,the dBm equivalent increases by+10. This is another basic charac-teristic that should be remem-bered.

When figuring amplifier gainby the dBm formula you fre-quently might be confronted withan input specified in millivolts in-stead of milliwatts. For example, amanufacturer says that with aninput of 4mV to a certain preampstage, his amplifier produces a10 -watt output. We want to knowthe overall amplifier gain in dBm.Assuming that the function

generator sine -wave output ismeasured across 600 ohms at 4mVon an RMS-reading TVOM, it ispractical to assume 4mV as zerodB and convert it to power with P= Ez Once the voltage readingR

is converted to power, you can pro-ceed with the regular formula forfinding dBm gain.

One practical advantage of thedBm formula, in which 1mW isalways P1 or the input, is the easeof determining the dBm gain orloss. Since log 1 (one) is zero, youneed only determine the log of P2and multiply by ten (move the dec-imal one place to the right) to ob-tain + dBm.

Simplifying Procedure

Because 10 times the log of theratio of the input and output pow-ers is either plus or minus dBm, bysubtracting the log of P1 from P2you can eliminate the operation ofdividing P2 by P1.

For example, an amplifier hasan input (P1) of 1mW and an out-put (P2) of 10 watts. Thus ,Inrw =io 10 -lox 10. 10,000

001 1 x 10" 1 1The ratio

is 10,000 to 1. The log of 10,000 is4.0000, and 10 x 4.000 is

30 I ELECTRONIC TECHNICIAN/DEALER, JULY 1975

Keep your eyes on'

A public servicebooklet to makeyourgood serviceeven better.

As an authorized Quasar TV servicer, you're aprofessional. Read this authoritative publicservice booklet published by the AmericanOptometric Association. Then give it to yourcustomers, and you'll look even more pro-fessional!

It contains some answers to questionsabout TV viewing. Among other things, you'lllearn whether TV affects the eyes, how muchlight there should be and that you should"...Adapt the set to the room lighting, not theroom lighting to the television set adjust-ment..." You know already that Quasar's"Super Insta-Matic" Tuning adjusts to roomlight... automatically!

To parents worried about children's TVhabits...to customers worried about viewingcomfort ...this non-commercialbooklet of the AmericanOptometric Association will be

The

a valuable leave -behind piece. AmericanTo obtain your supply, Optometrk Association

see your Quasar distributor inanwriends acjdstng Me TV

soon. tn changing mom lightand this set dors auttrnancaly

QuAsar

Quasar this year

ere be?r general any: -

tong tends

A new company with new solutions for today.

Seal Copyright 1975©Quasar Electronics Corporation

-4-

uasarElectronics CorporationA SubSdiary of Ma'


-ThMore

chancesto beright

Thousands morecross references

Transistor kitfor foreign sets

4:::)O1;;;J c:76)

140.)

Replacementamplifier modules

All the help you needat your authorized distributor

lube Products DepartmentGeneral Electric CompanyOwensboro, Kentucky 42301

GENERAL* ELECTRIC

+ 40dBm. Let's increase the input,P1, 10 times. The log of P2 (10,000)remains the same, but P1 has beenincreased from 1 in the ratio to 10and the log of 10 is 1.0000. So,4.000-1.0000 = 3.0000 x 10 =+30dBm.

Zero And Negative dBm

The preceding has brought us tothat much used by misused andmisunderstood twilight -zoneknown as OdB, or reference level.For example, = log 10 - log10 = 1.000 - 1.000 = 0.

If the input (P1) is increased bya factor of 10, the ratio becomes:

10 wattt Log 10, as before, is 1.000011)0 wat

and log 100 is 2.0000. We havenow arrived at that area of "lessthan nothing," or - dBm. At firstglance, it might appear that1.0000-2.0000 would give us-9.0000 x 10 = - 90dBm. But thiscan not be true because the inputhas been increased according topowers of 10 and should have aratio accordingly, or 0.1:1.

At this point, if you do not al-ready know, you must learn tomanipulate logarithms in thenegative area, which involvesmerely observing simple algebraicprinciples and certain rules oflogarithms. In the preceding prob-lem, the log characteristic of 0.1 is- 1. In common logarithms themantissa (the decimal fraction tothe right of the decimal, as pro-vided in common log tables) mustremain positive. The characteristic(the number to the left of the deci-mal) can be either positive or nega-tive. Additionally, for conveniencein figuring you can add 10 orhigher multiples to negativecharacteristics if you subtract the

TABLE 4DECIBELS

Current or Voltage Ratio Power

Gain

Ratio

LossdB Gain Loss0 1.000 1.000 1.000 11.0000

1.0 1.122 .8913 1.259 .79432.0 1.259 .7943 1.585 .63103.0 1.413 .7079 1.995 _50124.0 1.585 .6310 2.512 .39815.0 1.778 .5623 3.162 .31626.0 1.995 .5012 3.981 .25127.0 2.239 .4467 5.012 .19958.0 2.512 .3981 6.310 .15859.0 2.818 .3548 7.943 .1259

10.0 3.162 .3162 10.000 .100020.0 10.000 .1000 100.00 .010030.0 31.620 .0316 1000.00 .001040.0 100.000 .0100 10.000 .000150.0 316.200 .0031 100,000 C0010

same amount at the end. Forexample: ;t,7, = (log 10) - (log100) = (1.0000 + 10) - 2.0000 =11.0000 - 2.0000 = 9.0000 - 10 =-1.0000 x 10 = - 10dBm.

If we turn this last problem up-side down so that we have a 10watt input (P1) and a 100 wattoutput (P2) we will come up with+10dB, or the opposite "image" of-- 10dB.

Finding Power With dBm Given

We have the dBm zero referencegiven (P1 = 1mW) and the output(P2) given is + 40dBm. We want toknow the output power (P2). P2 =antilog dtBom = anti log 40r=4. An-tilog 4 = 10,000mW = 10 watts.

And on the minus (loss) side: P2= antilog 51111-m- = - 4. Antilog -4= 0.0001mW = 0.1µW = 1.00nW.To check the preceding computa-tion: - dBm =10 log =log 100 = 2.0000 + 10 = 12.0000 -6.0000 (log 106 nW) = 6.0000 -10= log - 4.0000 x 10 = - 40dBm.

The above formula for convert-ing - dBm to power when thespecified - dBm (the numerator) isnot evenly divisible by 10 must berevised somewhat to provide accu-rate results. Likewise, when a dif-ferent zero reference, say 6mW, isused, the formula is revised to: P2= 0.006 x antilog .

Voltage/Current dB FormulasA manufacturer's specs say an

amplifier has a 0.5V, or 500mV,input which provides an output of25V. Disregarding impedances,what's the dB voltage gain? dBV =20 log E' = 20 log '551=vv = log25,000 - log 500 = 4.3980 -2.6990 = 1.6990 x 20 = 34dBV.

The dBmV (or d13µV) system isparticularly useful for dealingwith antennas, especially MATVsystems. This method employs azero reference of 1,000 microvolts,or lmV. With it, computations arelimited principally to algebraic-ally adding the gains and losses ofthe various active and passiveelements in the system, whetherlarge or small. By employing thismethod, a "finger-tip" check canbe maintained throughout thesystem planning and installationprocedure so that each TV and FMoutlet will be provided with suffi-cient signal, which for TV sets isnormally considered to be lmV (or1,000 microvolts) for adequatecolor TV reception. III

32 ELECTRONIC TECHNICIAN/DEALER, JULY 1975

Your VTVM is obsolEtE!This may sound like a harsh

claim, but it's true. Thousands of TVtechnicians are using instrumentsdesigned in the 1950's to trouble-shoot circuits designed in the 1970's.

And now, most color TV's havesolid state circuits. So use ofout-of-date test equipment justcompounds the problem.

The generation gap has growntoo big.

The Fluke 8000A 31/2 digit multimeter

Solid state calls for newperformance standards.

Your "old fashioned" test equip-ment simply doesn't measure up totoday's requirements. For example,the typical VTVM gives you 5%accuracy and 2% resolution. In theold days, that was good enough.Not so today.

Now you need an instrument tolook at the voltages at each pin of anIC with sufficient accuracy andresolution to determine proper ICoperation.

For example, a reading of "around2.8 volts" is no longer sufficient.You must be able to distinguishbetween 2.80 and 2.82 volts.

You need a test instrument thatgives you 0.1 ohm resolution so youcan reliably measure resistance ofswitch contacts, circuit breakers,and low value resistors.

To do all this and more, you needthe superior capabilities of theFluke 8000A 31/2 digit multimeter.

An instrument designed specificallyfor testing solid state equipment.

The 8000A gives you up to 50times the accuracy and 20 times theresolution of a VTVM, so you canmeasure the various voltage levelsin a solid state chassis withabsolute confidence.

1710r--

SU-L. COMMON

ICI IC MN

I I0111111allarri I 1

rINCTIIN NANCE galNCI IC MA NC 2110 ina 2 21 211 mato

1101Illi MULTI

POWER

ON -01F

Resolution is 100 microvolts, 100 nanoamps and 100 milliohms

You get the sensitivity you needfor low level dc measurements. The200 millivolt range with 100 microvoltresolution tells you exactly whatyour values are.

The 8000A has an AC frequencyresponse from 45 Hz to 20 KHz and,with accessory probes, to 500megahertz. Resistance measuringcapability ranges from 100 milliohmsto 20 megohms. It offers a 15°C to35°C accuracy temperature span.And a 1 -year accuracy time span,meaning it seldom needs calibration.

Unlike other DMM's the 8000Ahas fast response time -3 readingsa second. And the bright, digitalreadout means that no interpolationis necessary.

The 8000A measures highvoltages, too.

Our 8000A is designed to answerall the needs of an electronic servicetechnician.

One very important (and talkedabout!) safety requirement is that thepicture tube anode voltage mustnot exceed the maximum specifiedby the manufacturer. Our 8000A hasan optional high voltage probe thatgives you guaranteed accuracy of1% at 25,000 volts. The probe alsoextends the capability of the 8000Ato 40,000 volts to measure the highvoltage in the new 32,000 voltchassis.

No other DMM's offer this feature.

High voltage probe accessory givesyou 1% accuracy at 25,000 volts

For data out today, dial our toll -free hotline, 800-426-0361

John Fluke Mfg. Co., Inc., P.O. Box 7428, Seattle, WA 98133

Get the most up-to-date instrumentavailable.

Don't be caught in the typical trap.Many electronic service shops don'treally update their equipment whenthey decide to update. Switchingto a TVM or a FET voltmeter doesn'treally give you the accuracy andresolution you need today, or forthat matter, tomorrow.

But with the 8000A on hand, youknow you have a true solid statetesting device ... an instrumentthat can do the job the way it shouldbe done.

Carry it anywhere. Use it on line or withoptional rechargeable battery power.Note the conveniently mounted specson the bottom decal. They're alwayswith you.

The 8000A comes from Fluke, oneof the largest instrument companiesin the U.S.

It costs just $299 ($40 more withHV probe). * And it is far and awaythe largest selling, most rugged andreliable 3V2 digit multimeter inthe world. Domestic only.

FLUKEJULY 1975, ELECTRONIC TECHNICIAN/DEALER 33

Circle #111 for information, circle #112 for demonstration

Power SupplyRegulator Circuits

How they function and how to service them

By Joseph J. Carr, ET, D Contributing Ed for

There are a number of reasonswhy equipment manufacturers goto the expense of incorporatingregulated DC power supplies intotheir equipment. In FM receivers,for example, the local oscillatorwill drift all over the band if anunregulated power supply is used.This is why most FM receivers usea regulated supply at least in thetuner stages.

On the other end of the spec-trum are certain audio amplifierdesigns which are able to operatewith lower distortion when regu-lated voltage sources are used tosupply the driver and pre -driver.

Another aspect of regulatedsupply application is the inherentreduction of power supply ripplecomponent in high -gain audioequipment. The source of suchripple is rectification of AC sinewaves. Fig. 1 graphically demon-strates the superior ripple reduc-tion of a solid-state regulatedpower supply. Both traces weretaken using the same "volts/div."factor for the vertical amplifiers.The upper trace is the waveformwhich appears across the output ofthe diode rectifier. From this pointto ground there was a 250-mfdelectrolytic capacitor. The lowertrace was taken using the sameoscilloscope deflection factor, butfrom the output of the regulator.

Note that although the input voltage to the regulator exhibits about240 millivolts of ripple, there ispractically none at the output. Itwould take a very large capacitorto reduce ripple this much in aconventional power supply circuit.In fact, one manufacturer of autoradio bench power supplies, Delco,used to advertise that their "elec-tronically regulated" power sup-ply has the equivalent of 1.0 faradof filtering. What they meant wasthat electronic regulation reducedripple to a level that would haverequired a liarad filter capacitorfor comparable ripple reduction ina conventionally designed powersupply.

Regardless of the type of equip-ment being serviced, I have foundthat odd and/or multiple troublesymptoms occur when incorrectvoltages and/or excessive rippleare applied to circuits. This hap-pens so often that I have made it astandard procedure to use both avoltmeter (amplitude) and a scope(ripple) to check power supplieswhenever odd, unusual or multi-

symptom situations are encoun-tered.

THE NEED FOR REGULATION

There are two basic reasons whythe output voltage of a power sup-ply will vary: 1) changing input

Fig. 1-Top waveform reveals 240mV of ripplepresent at a point immediately preceding thevoltage regulating circuit of a power supply. Bot-tom trace. taken at the output of the regulatorcircuit, reveals the significant reduction of ripplewhich a regulator is capable of achieving. Bothtraces were taken with a dual -trace scope withboth vertical amplifiers set for equal gain.

(INTERNALoi RESISTANCE

OF POWERSUPPLY)

VOLTAGE- SOURCE(SUPPLY)

I(LOAD

CURRENT)

E OUT R2(RESISTANCEOF THE LOAD)

E OUT = E_( R2 _)R R'Z

Fig.2-Equivalent circuit of a power supply andits load. R1 represents the internal resistance ofthe power supply itself and R2 represents thevarying resistance of the circuits to which thepower supply furnishes operating voltages. Alsoshown is the formula for computing the voltageoutput of a supply.

voltage, and 2) changing outputload conditions. The former isespecially a problem in automo-tive electronics and in those areaswhere the power mains are over-loaded.

The latter problem, changingload conditions, can be better un-derstood by referring to Fig. 2. Allpractical power supplies can berepresented by an "ideal" voltagesource, which has zero internalseries resistance, and a series re-sistor (R1) which represents thetrue series resistance of an actualsupply.

The total variable resistance ofthe various individual circuitswhich the power supply feeds inparallel is represented in Fig. 2 bya single variable resistance, R2,which is in series with the internalresistance (R1) of the supply. Be-cause the conduction of the stagesrepresented by R2 varies, so dotheir individual resistances andthe resultant current drain (load)on the power supply. When thevalue of R2 decreases (increased


R1 A

E UNREGULATED E REGULATED

1/1

R2

E UNREGULATED

I iE REGULATED

R3 1.

E UNREGULATED E REGULATED

D1

Fig.3-Three basic types of shunt regulator devices: A) gas regulator (0A2, 0B2, etc.), B) Neonglow lamp (NE -2, NE -51, etc.), C) Zener diode.

current drain, or load), the outputvoltage of the supply also de-creases, as will be verified if youmentally plug various values intothe voltage output formula inFig.2.

To prevent the output voltage ofthe supply from decreasing as thecurrent drain (load) increases, it isnecessary to maintain a constantratio between the internal resis-tance of the power supply (R1) andthe load resistance (R2). Forexample, if R2 decreases (in-creased load, or current drain), thevalue of R1 should be made to ef-fectively decrease a proportionateamount, so that the output voltageof the power supply will remainrelatively constant. This is voltageregulation.

Such regulation can be ac-complished by two basic methods:

1) A variable resistance whosevalue automatically adjusts tochanges in the load of the powersupply can be placed in parallel toR2 so that as R2 decreases (loadincrease) the parallel variable re -

E

VzI

I

E

Fig. 4-Current-vs-voltage character stics of a Fig. 6- Typical IC -equipped power supplytypical Zener diode. regulator circuit.

Fig. 5-Series-pass regulator circuit.

sistance increases a proportionateamount, to keep the effectivevalue of R2 relatively constant.

2) A variable resistance whosevalue automatically changes in-versely to changes in the powersupply load can be placed in serieswith R1 so that as the value of R2decreases (increased load) the ef-fective total value of R1 and theadditional series resistance alsodecreases a proportionate amount,to maintain a constant ratio be-tween the values of R1 and R2.

BASIC SHUNT -TYPEREGULATING DEVICES

Fig. 3 shows several shunt -typedevices used to regulate powersupply outputs. Fig. 3A is a cold -cathode gas tube, which was usedfor many years in vacuum tubeequipment. Fig. 3B is anothergas -type regulator, a neon glowlamp.

Both of these types of gas -filleddevices provide regulation be-cause the voltage drop across anionized gas cell tends to remain

U1

E E OUT

0

GROUND INTERRUPTED AT "X" FORSERIES POTENTIOMETER TO TRIM

EOUT IN SOME CIRCUITS

Fig. 7-Three-terminal voltage regulator de-vice. Because some are packaged in TO -typetransistor cases, they often are mistaken fortransistors.

constant even though the currentthrough it changes.

In other words, the internal re-sistance of a gas regulator changesinversely when the voltageapplied changes.

Fig. 3C is another type of shuntregulator device, the Zener diode.These devices have a peculiarvoltage -current characteristiccurve, which is shown in Fig. 4.Note that when the PN junction ofthe diode is forward biased, thecurrent flow is identical to that ofany solid-state diode. However,when the Zener diode is reversebiased it operates somewhat dif-ferent than a conventional solid-state diode. When a normal PNjunction is reverse biased, no cur-rent flow occurs. In a Zener diode,this is true only up to the pointwhere the reverse -bias voltagereaches a critical value known asthe Zener voltage. When this volt-age is applied to the junction, it"breaks down" and begins con-ducting current.

Between zero volts and Vz, the


Zener diode exhibits the large re-sistance associated with anyreverse -biased semiconductordiode. At voltages from the Zenerpoint on up, though, the Zenerdiode has a very low resistance.This characteristic allows theZener to be used as a shunt -typeregulator, provided that the seriescurrent can be limited to a safevalue by .R3. Although it tends tochange slightly with changes intemperature, Vz is stable enoughto provide relatively good regula-tion.

SERIES -PASS REGULATING CIRCUITS

When either critical stability ormore flexibility is needed, otherregulation techniques and circuitsare used. Some are discrete transistor circuits (Fig. 5), whileothers use either special ICs (Fig.6) or three -terminal devices (Fig.7).

One popular IC regulator, theUA723, comes in several packagestyles and is flexible enough to befound in a wide variety of equip-ment.

Three -terminal regulators arerelatively new but already arebeing used in consumer electronicequipment. Because they come inTO -3, TO -66 and plastic transistorcases, they can easily be mistakenfor transistors. If service informa-tion is not available, circuit loca-tion and the lack of other compo-nents (such as a Zener diode andresistor at the "pseudo -base" ter-minal) are the best means of iden-tifying a three -terminal reg-ulator. This can be an especiallyaggravating problem if the setmanufacturer uses "house num-bers" to identify semiconductorsand yet offers inadequate servicedata.

Fig. 5 is a series -pass transistorregulator. Note that regulator ac-tion in the series -pass design is ac-complished by effectively raisingand lowering the resistance of theseries -pass element of the reg-ulator circuit.

This circuit increases the cur-rent range of the regulator and"amplifies" the regulating effectsof the Zener diode which is used tostabilize the transistor base. Be-cause collector -emitter resistanceis dependent on base -emitter bias,

Fig. 8-This series -pass type of regulator circuitis s miler to that in Fig. 5 except that a secondtransistor. 02. is used to control the base ofseries -pass transistor 01 instead of it being controlled directly by Zener diode D1. This circuitarrangement provides closer regulation thanthat in Fig. 5.

Fig. 9-A series -pass regulator circuit which iscontrolled by a differential operationalamplifier.

the base of Q1 is held at a fixedvoltage by Zener diode Dl. Whenthe demand for output load cur-rent decreases, the emitter volt-age increases, causing the base -emitter bias to decrease slightly.This, in turn, causes the transistorto pass less current, thereby effec-tively increasing the collector -emitter resistance in series withthe load.

When the demand for load cur-rent increases, the emitter voltagedrops and, because this increasesthe forward bias of the base -emitter junction, the transistorconducts even harder. This, inturn, lowers the collector -emitterresistance, causing the outputvoltage to increase back to thesteady state value.

For a regulator equipped withan NPN transistor, the steadystate output will be close to (Vz +

E IN

RI

E SOURCE

O

GISERIES -PASS

AMPLIFIERCONTROLAMPLIFIER

COMPA-RATOR

R S

REFERENCESUPPL

D2

A

EOUT

-0

SENSE AMPLIFIERHERE. IF USED

03 D.

Fig. 10-Block diagram of a more complicatedseries -pass regulator (A). in which a reference(B) is compared with the output voltage.

Fig. 11-A switching, or flyback. type of reg-ulator (A). which uses a variable duty cycleswitching system to control the output voltage. Asimplified illustrative schematic of this systemis shown in (B).

Vbe) or (Vz + 0.7). For a regulatorequipped with a PNP transistor,the steady state output voltagewill be about 0.7 volts lower thanthe Zener voltage (Vz). This is agood guide for selecting replace-ment Zeners in the absence ofcross-reference data.

Figs. 8 and 9 show similar butmore complex designs of series -pass regulator circuits. A secondtransistor, Q2, with a Zenerstabilizing its emitter voltage, isused in Fig. 8 to control the base ofthe series -pass transistor Ql. A


RECTIFIER

110 V,!1_60HZ

CHOPPERs

LC FILTERGCS r- - -

L

WEEPER

DRIVER

RUE StWIDTH

MODRATOR

ER ORAMP

130 V REGULATED

r

Fig. 12-Block diagram of the switching type of power supply and regulator used in Sony's KV-1722Trinitron color TV receiver.

REGULATOR

_L CIRCUITS

SCR1RD

RD

EA EOUTRRt ,2

E OUT

Fig. 13-SCR "crowbar" protection circuishown here blows fuse if either the series -passtransistor or Zener fail in a way that causes anexcessive output voltage.

REGULATED POWERSUPPLY FAILURES

(Based on 37 IndividualIncidences)

COMPONENT TOTAL PERCENTAGE

WHICH NUMBER OF TOTAL

FAILEDZener Diode 17 46%Series -PassTransistor 14 38

All Others * 6 16

'Four of these were the "other" transistor in cir-cuits such as Fig. 8.

sample of the output voltage, inturn, drives the base of Q2 viavoltage divider R1 and R2.

The circuit of Fig. 9 uses a Zener(D1) to stabilize one input of a dif-ferential IC operational amplifier(U1), while a sample of the outputvoltage is applied to the other dif-ferential input via voltage dividerR1 and R2. The output voltage,which controls the base of theseries -pass element, is propor-tional to the differential inputvoltage.

COMBINATION REGULATORS

Regulated power supplies comein several varieties, and you canexpect to see more than one type insome equipment. For example, a

recent color TV chassis and sev-eral FM receivers use a simpleZener to regulate some voltages,but for regulation of more criticalvoltages, they use a series -passtransistor or op -amp design.

More complex equipment, ofcourse, requires more complexregulators. An example of such aregulator is block diagrammed inFig. 10A. Q1 is the same type ofseries -pass transistor used in lesssophisticated circuits. Its base,however, is controlled by anamplifier (either discrete transis-tor or IC) driven by a voltage com-parator circuit. Output currentgenerated by the control amplifieris steady as long as the referencevoltage (Fig. 10B) and the outputof voltage divider Rl/R2 (or senseamplifier) are equal. Changingload conditions, however, makethe output of voltage dividerR1/R2 vary, which causes thecomparator to either increase ordecrease the output of the controlamplifier.

SWITCHING REGULATORS

Fig. 11 shows the block diagramof a modern, very efficient powersupply called the switching reg-ulator or flyback regulator. Fig.11B is a simplified version.

Consider the electrical situationacross the load in Fig. 11B whenswitch S1 is closed. Output voltageis zero and the current is limitedonly by any series resistance inthe power source or inductor Ll.During this period, energy isstored in the magnetic fieldaround Ll. When S1 is opened,this field collapses and dumps acountervoltage into the circuit,producing an output voltage equalto the source voltage plus thecountervoltage. This voltage willdecay to the value of the source

voltage if the switch is left openlong enough for the field to dis-charge completely.

In actual circuits, switch S1 willbe a shunt transistor such as Q1 inFig. 11.A. A multivibrator or oscil-lator supplies a pulse train whichdrives a pulse width modulator(PWM) to electronically "toggle"Q1. Use of a PWM causes theon/off state (duty cycle) of Q1 tovary in response to changes in theoutput voltage.

Sony uses a switching powersupply in their KV1722 and otherTrinitron chassis which is similarbut not identical to the circuit ofFig. 11. A partial functional dia-gram of the KV-1722 switchingpower supply is shown in Fig. 12.The electronic switch is a SiliconeControlled Switch (SCS) whichSony calls a Gate ControlledSwitch, or GCS. This device is aPNPN switch which behaves simi-larly to a flip -flop -connectedPNP/NPN pair (hence the two -arrow symbol). Each "transistor"in the pair regeneratively drivesthe other, causing an increased,more nearly perfect, switchingtime. A low-pass filter at the out-put of the supply reduces the prob-ability of hash from high -frequency switching transients,which would interfere with othercircuits.

TROUBLESHOOTING PROCEDURES

Troubleshooting the more com-plex regulators can be tricky be-cause they are negative -feedbackcontrol circuits. Once you are cer-tain that the reference voltagesource is operating normally,check the series -pass element.After that, test the rest of thesemiconductors.

Analysis of one month's servicerecords kept by one service shopwith which I am familiar revealsthat in 37 repairs of regulatedpower supplies the componentfailures by percentage of typewere as shown in the accompany-ing table. From this table it can beseen that the fastest approach totroubleshooting is to check thehigh -failure -rate items after firstdetermining that the referencevoltage source (if used) is function-ing normally.

Then check the negative feed -


back aspect of the circuit.One word of caution regarding

equipment equipped with supplieswhich come in with a blown fuse:don't replace the fuse and turn onthe set until the series -pass ele-ment and the Zener have beenexamined. The reason for this pre-caution is that some regulatorsare equipped with a protection cir-cuit, like that in Fig. 13, whichblows a fuse whenever excessivevoltage appears at the output.This circuit remains inert as longas the sample of the output voltageat point "A" is too low to supply asufficient current through R3 totrip the gate of the SCR. If theregulator should fail in a mannerwhich places excessive voltage ac-ross the output, a larger currentwill flow in R3, and the SCR willbe gated on. This causes theanode -cathode resistance to dropto a fraction of an ohm, drawingenough current to pop fuse Fl.

Some technicians merely checkthe output line with an ohmmeterand, if no short is found, they re-

place the fuse and try a "smoketest." The only trouble is that,after blowing the fuse, the SCRand all other circuits return totheir normal "off" conditions (ex-cept for the fuse and the failedcomponent.) Once the fuse is re-placed without finding the cause,the whole cycle repeats itself.

One of my early employers, Nel-son Moodie, of Colonial Radio inArlington, Va., used to have a say-ing (among many): "Fuses don'tcause trouble, they indicate trou-ble!" Moodie's admonition goesdouble for SCR "crow -bar" pro-tected supplies such as that in Fig.13.

Another difficulty encounteredin the servicing of regulatedsupplies is the possibility that ashort in the equipment, not in thepower supply itself, caused thefailure of the supply circuits. Toeliminate this possibility, use abench supply, or combination ofsupplies, if needed, to substitutefor the set's supply long enough totest the rest of the circuitry. These

supplies, which are available froma number of sources, includingRCA, Heath and Kepco, includecurrent -limiting protection. Dis-connect the set's power supply(even if this means a razor cut onthe PC foil) and connect in the"outboard" power supplies.

Once you are satisfied that theset is working, replace the defec-tive components and reconnect theset's internal power supply.

CAUTION: Should you tryusing two or more electronicallyregulated bench supplies in paral-lel to increase their current capa-bility, you might run into a prob-lem whereby the two supplieskeep fouling up each other's volt-age sensing circuits. In one type ofsymptom, the breaker of one sup-ply will trip and the other will beforced to supply all current re-quirements.

Another symptom occurs withsupplies equipped with auto -resetbreaker. Supply A will shut downSupply B, which shuts down A,which shuts down B, etc.

FOR INNOVATIONS IN LOW-COST TEST EQUIPMENT, THINK HP

A professional 80 MHz counter for $275.The HP 5381A counter covers 10 Hz to 80 MHzwith the highest performance available for themoney: Sharp seven -digit LED readout. Highstability internal time base. 25 mV sensitivity.Three -position input attenuator. External oscillatorinput. Ratio measurement capability. Extremelyrugged dust -free case.Ideal for applications such as production linetesting, service and calibration, frequency moni-toring, education and training.

Or go all the way to225 MHz for just $450:The HP 5382A counter has all the features of the5381A over an expanded frequency range of 10 Hzto 225 MHz. Plus an eight digit display and op-tional temperature compensated crystaloscillator ($100)*.As you might expect from HP, both counterscome with the same warranty and service back-upas our costliest test equipment. And both meetIEC safety specs.For complete information call your nearbyHP field engineer. Or, write.

\ 02406A *Domestic USA prices only

-1 ,_ 1:1I 1_1. I_1

0 1_ :11 1 1_1 _I

LINE

GATE TIMEis

If

MN,

NEW

TO, Hi

121'425381A 80 MHz FREOUENCY COUNTER

X10

ATTEMUATORAI

INPUT

HEWLETT PACKARD

HEWLETTig PACKARD

Sales and service from 172 offices in 65 countries.1501 Pa3e Road Palo AII0 Ca,,C,^ a 44304

,, Nreo5


38 / ELECTRONIC TECHNICIAN DEALER, JULY 1975

When you replace withASTATIC

phono cartridges & needlesyourprofits are at a peak.

Only Astatic, the world's most complete lire, givesyou one -source supply for EVERY need. factoryoriginal fit and performance EVERY time, maximumprofit EVERY time through absence of customercomplaints and call backs. Impois and cheap sub-stitutes cost yot. more than meets the eye! Michmore.

THE ASTATIC CORPORATION / Conneaut, Ohio 44030 U. S. A.In Canada: Canadian Astatic Ltd., Scarborough, Metro Toronto, Ontario

Export Sales: Morhan Exportin Corp., 270 Newtown Rd., Plainview, Nev. York 11803, U. S. A.

ASTATIC - The Biggest Name In Phono Cartridges, Needles, Microphones


JULY 1975. ELECTRONIC TECHNICIAN/DEALER 39

TEST INSTRUMENT REPORT

.000 KM

A diode and three fuses protect the TriplettModel 60 from overload damage. For more in-formation about this instrument circle 100 on theReader Service Card.

TRIPLETT MODEL 60 VOM

The most important interestingfeature of Triplett's Model 60VOM is its ability to withstandmisuses and hard everyday servic-ing needs.

The instrument has built-inprotection against accidental highenergy overload, is shock resistantto accidental drops up to a five footheight, modular constructed sothat it can be quickly serviced inthe field, and is designed to meetrigid safety standards to preventelectrical shock.

After throwing the instrumenton the floor a few times and apply-ing an AC input voltage, with theinstrument set to the ohms range,no detectable harm was noted tothe instrument or its accuracy. Wewere quite convinced it could takea lot of abuse.

Safety Features

To help eliminate destructionfrom accidental drops, the instru-ment features a case of moldedblack, high impact thermoplasticmaterial, in combination with asuspension meter module whichliterally floats inside the outercase. The case finish has a non -slip"finger -tread" surface finish forhandling ease.

The meter movement is pro-tected by a diode module and toprevent harm from normal over-

Triplett's Model 60 VOM is shock -resistant toaccidental drops up to five feet

load conditions it is protected by a2 amp, 1000 volt (20 KW on DC; 30KVA on AC) fuse and two zenersare used to protect the instrumentagainst high energy fault currentsand provide protection of the test-er circuits up to 1000 volts.

A separately sealed batterycompartment permits external ac-cess to the batteries and fuseswithout removing other parts ofthe instrument. Also found in thiscompartment are a spare 1/8 ampand 1 amp fuses. There are no ex-posed parts, this design insulatesthe user from the instrument it-self. It also provides an internalelectrical system which preventsexplosive arcs in high energy cir-cuits up to 2 amps, 1000 volts fusecapacity. The test lead jacks on thefront panel are recessed safetyconnectors and a large imprintedlabel spelling out the safety pre-cautions to observe when usingthe instrument are additionalsafety features.

Construction Features

The instrument employs a 45 µasuspension movement with a 41/2inch scale. It is contained in aseparate protective housing ofmodular design which can be re-

moved and replaced in a shorttime in the field if necessary. Onlytwo connecting wires require re -soldering to put the tester backinto operation. The removal ofeight screws completely disas-sembles the instrument.

The single range selector switchhelps to prevent incorrect settingsand enables you to select any oneof the 28 ranges. The scale in-cludes markings for direct read-ings when employing the optionalClamp -on AC Ammeter.

Also featured is a special"Confidence -Test" feature whichis built into the unit for periodicreassurance checks of its meter.

Measurement Ranges

DC Volts. Ranges: 0-1, 3, 10, 30,100, 300, 1000 Volts at 20,000Ohms/Volt. ± 2 percent of fullscale all ranges. AC Volts. Ranges0-3, 10, 30,100, 300, 1000 Volts at5000 Ohms/Volt. Accuracy is + 3percent of full scale all ranges. DCCurrent Ranges: 0-0.1, 10, 100,1000 Milliamperes at 320 Mil-livolts. Accuracy is + 2 percent offull scale all ranges. ResistanceRanges: 0-1K, 10K, 100K, 1M,10M, (12, 120, 1.2K, 12K, 120Kohms center scale). Accuracy is +2 percent of arc length. Decibels.Range: -20 dB to +52 dB Accu-racy is + 2 per cent of full scale allranges. Output volts (AC) Ranges:0-3, 10, 30, 100, 300 volts at ap-proximately 5000 ohms/volt. Ac-curacy is + 3 pecent of full scale allranges.

The instrument measures ap-proximately 31/4 inches by 51/4inches by 71/4 inches and weighs2% pounds with batteries (1-9 volt,and 1-1/2 volt "D" cell).

The instrument comes completewith safety test leads, insulatedalligator clips, batteries, spare 1/13amp and 1 amp fuses and instruc-tion manual. Price is $90.

LECTROTECH MODEL TO -60OSCILLOSCOPE

There are growing needs for adual -trace oscilloscope in thehome entertainment equipmentservicing. The dual trace scope,used in industry and labs for manyyears, is appearing on servicebenches with increasing numbers.

Lectrotech's Model TP-60 solid


Lectrotech Model TO -60 Automatic Dual -TraceOscilloscope. For more information about thisinstrument circle 102 on the Reader ServiceCard.

state, 15 MHz, dual trace trig-gered sweep, oscilloscope permitsdual display of waveforms in fivemodes, allowing you to comparethe waveforms for shape, ampli-tude and time duration.

Features

Automatic Triggering Sweeptriggers solidly on all signalswithin the rated band width. Au-tomatic Astigmatism Spot defini-tion is always clean and sharpover entire CRT screen. Automa-tic Horizontal Sweep Special cir-cuit provides free -running hori-zontal sweep in absence of trigger-ing signal in the ground/free-runposition. The time base remains athigh brightness for all sweepspeeds. Automatic Horizontal!Vertical Triggering. When view-ing video signals, the horizontaland vertical triggering is selectedautomatically by the time baseswitch.

TV trigger selector automati-cally converts the trigger amplifi-er to an amplitude selectable SyncSeparator. This feature providesstable triggering on composite TVvideo signals. Unique trigger cir-cuit provides automatic triggeringto frequencies in excess of 15 MHzwith as little as 1 division of dis-played signal. It is an ideal in-strument for the display of sweepalignment response curves. TheDC coupler amplifiers providemaximum stability for thesecurves and minimize the need forboth oscilloscope and sweeper ad-justments and it is compatiblewith all existing sweep genera-tors. Channel A or Channel B cantrigger independently of each

THERE ARE TWO GOOD WAYSTO CARE FOR TIMERS...And they're as different as Night and Day.

SEW-IMPROVEO124" FLEXTENSION

INSIDE THE CAP

24" 50%Fannon MORE

INSIDE inCRP

41161.11-

1111" St luent

:Viuhritant"I Ibrusiu es

KEEP AWAY FROM CHILDREet` side panel for precautions.

FIRSTAlO

FOR

moos

Tiny Miniscrubbers imbedded Washes clean and leaves a soft,in a thick coating of polish. slick non sticky film.

As popular as ME Sniff is ... a lot of technicians justprefer an old fashioned solvent -lubricant. So we decidedto invent a brand new old fashioned solvent -lubricantfor them. Fi/ is unquestionaLly the finest tuner solvent -lubricant to come along. It washes clean and leaves aslick but not sticky film. And we still have BIIIE STUFF

So now you get to do it your way. ..and either way the best is from

TECHSPRAY

where we find solutions for your problems

...for more details circle 126 on Reader Service CardJULY 1975, ELECTRONIC TECHNICIAN/DEALER 41

T & T VALUE SALERAYTHEON, I.C.C.. RCA. SYLVANIA

FAMOUS MAKE, NEW JOBBER -BOXED TUBESNOW WITH NEW 5 -YEAR GUARANTEE

80% Off LIST

1V2 5 for 53.00 0 6HA5 5 for $4.802AV2 5 for $3.90 u 6HQ5 6 for $6.353A3 for 55.05 0 6H115 6 for 11.803AT2 5 for 0 8JC6 5 for $5.6530 85 5 for $4.85 0 8.1E6 6 for 11.153HA5 5 for $4.80 0 6JS6 6 for $9.303HM5 5 for $4.80 IICI EIJU8 6 for $5.555GH8 5 for $6.90 LJ EIKA8 5 for $9.15O 6AY3 6 for $5.05 0 6KE8 6 for $7.65O 6BK4 6 for $9.35 0 61(78 5 for $6.856003 5 for $4.95 10 6KZ8 6 for $5.156C08 5 for $6.40 D 6LB6 5 for 10.756CJ3 6 for $4.70 0 SLOG 5 for 11.158DW4 6 for $4.70 JI 8FQ7 6 for 3.75SEAS 5 for 54.95 0 12BY7 5 for 4.50

8FQ7 5 for $3.758EJ7 5 for $4.50 17JZ8 5 for 4.50

23Z9 5 for 6.00

6EH7 5 for 54.80 12GN7 5 for 7.00

60F7 5 for 56.65 0 33GY7 5 for $8.0560H8 5 for $3.95 0 36MC6 5 for 11.406GJ7 5 for $3.40 0 38H E7 5 for $9.20

O 6GM6 6 for $5.25 0 38HK7 6 for 9.00O 6GU7 6 for $5.25 U 42K N6 6 for 9.15

What is not advertised -write in at 80%Off List!

O One FREE 613H8 for every 5 Tubespurchased.

O A6GH8 SPECIAL 100 for $49.00ALL SYLVANIA TUBES 70 & 100/. OFF

LIST -SLEEVES ONLYTRANSISTORS XACT. REPLACEMENT (BOXED)

Up To 85% off LISTSK ECG

O 3009 102A 10 for $5.85O 3018 121 10 for $3.38O 3021 124 10 for $4.73O 3041 162 10 for $6.30O 3052 131 10 for $5.85

3054 184 10 for $8.753083 183 10 for $8.303084 196 10 for $7.203103 157 10 for $4.503114 169 10 for 53.60

O 3115 186 5 for $12.40O 3124 123A 10 for $3.15O 3132 10 for $3.90O Zen. 212-46 6 for $10.00LARGE DISCOUNTS ON ALL TEST EQUIPMENT

O B & K Precision Portable Digital Multi -meter Model 280. Reg. Price $99.95 -Our Price $85.00

DIODES & RECTIFIERSROA Damper Diode Equiv. To:

O RCA 120818 $1.35 0 RCA 185832 $2.95O 8500 PIV Color Focus Rect. 10 for $5.000 2.5 amp 1000 PIV 1R170 100 for

D1304 Zen. Voltage Trlpler 212-136 2 for 8.00

10 for 2.600

YOKES - TUNERS - FLYS EQUIV.O Y94 0 Y105 0 Y107 Y109

Y119 0 Y130 0 DY107AC 95.2779 0 Syl. 51-29978-E01O Phllco 76-14328-1 ID Philter> 76-14328-

2-1 ea.O 4 Asst. Tuners, New $$105..9005El 4 Asst. Combo Tuners, New 515.00AUDIO -CARTRIDGES -SPEAKERS -NEEDLES REPL.

60 Min. Cassette Tape 12 for $4.0060 Min. Irish Cassette Tape 12 for $8.0090 Min. Cassette Noreico type box

12 for 510.0084 Min. Irish 8 -track Tape 6 for $8.0084 Min. Shamrock S -track Tape 7 for $6.0040 Min. Shamrock 8 -track Tape 8 for $4.008 -Track Head Cleaner 5 forCassette Head CleanerEmerson Mikes

10 for 4.0010 for 4.00Equly: 0 N77 0 876 8910 Shure 44 0 PickerinV15 ea. 52.95 B5R Cart. 0 132M5 Cl SKIM

E SCSM 4 for $8.0012 Asst. Needles Incl. Diamond $4.95BSR Adapters (45) 6 for S2.005 x 7 Speaker with Grill. pre -wired.3 -position Rotary Switch. ea. $2.95O 6 x 9 Speaker with Grill, pre -wired,3 -position Rotary Switch. ea. $3.95El 3 Stereo Headphones $10.00

E Universal AC Adapter. By. 75V, 9V $4.95Cl 2 of each: 4". 5", 6". 2x4", 406",3x5". all 12 for $13.96

NEEDLESO BSR 1M E 3M [Ti 5M 12 for $4.95 Tetrad TD9 Universal 12 for $4.95 Electro Voice EV 13M 12 for $4.95

ANTENNAS10 300 ohm 2 -Set Coupler 10 for 57.500 300 ohm 4 -Set Coupler 10 for $10.00O 72 ohm to 300 ohm Matching

Transformer 10 for $7.500 72 ohm Signal Splitter 5 for $5.00O 59 OF Connectors 100 for $10.00Ei 8 Antenna Clothespins $1.18

GENERALO 19 & 25" 0 21"

Color Boosters 3 for 511.95 Belfuse 2250.1 25 for $2.50 NV 30K V Anode Leads 6 for $1.290 SHUNT REG. HOODS (681(4) 3 for 51.29n Color CRT Harness 8 for $1.29

T & T SALES CO.4802 AVENUE K

BROOKLYN, N. Y. 11234Phone: (212) 241-5940

other in single channel modes. Indual channel modes the triggeringis provided by channel A.

Other features include: vec-torscope input for color TV servic-ing, external horizontal amplifier,external horizontal input, cali-brated horizontal time base, TVsync selector, and calibrated ver-tical attenuator.

Specifict3ons

Vertical Amplifier Bandwidth:DC to 15 MHz min. Risetime: 23nano seconds. Sensitivity: .01volts/div. to 20 volts/div. in 1-2-5step sequence plus continuouslyvariable control. Input Impedance1 Megohm + 1 percent shunted by30 picofarads Horizontal SweepType: Miller Integrator SweepSpeeds .2 second/per division to .5micro second/per division in 1-2-5step sequence plus continuouslyvariable control. With 5X mag-nifier sweep speed increases to 11micro second/per division. Trig-gering Source, Internal externaland line Type: Automatic oramplitude selection with presetstability External HorizontalAmplifier Bandwith: DC to .5 MHzSensitivity: .5 volt/per divisionInput Impedance: 100 K shuntedby 30 picofarads Cathod Ray TubeDisplay Area: 8 by 10 Cm Blank-ing: DC coupled.

Size and Weight

The instrument measures 9inches high by 10 inches wide by131/4 inches deep and weighs 25pounds. The price is $489.50.

SYSTRON DONNER MODEL 7004ADIGITAL MULTIMETER

The Systron Donner Model7004A Digital Multimeter is a fullfour -digit instrument. It offers thefive selectable functions of DCvoltage, DC current, AC voltage,AC current and resistance.

Some of the outstanding fea-tures of the unit include highinput impedance on the three mostsensitive ranges, extended ACfrequency response, new ease ofcalibration, and improved serv-iceability.

All function and range selec-tions are made from the front -panel pushbutton controls. Thereadout features a nonblinking

Systron Donner Model 7004A Uigital Multimeter.For more information about this instrument cir-cle 103 on the Reader Service Card.

display of four full digits plusoverrange, auto -positioned deci-mal point, and an indicator foroff -scale readings. Polarity indica-tion for DC voltage and current isautomatic with a minus indicatordisplay.

Resolution and Accuracy

All measurements are madewith 0.01 percent resolution on afull four -digit display. A fifthreadout digit allows 30 percentoverrange capability. Accuracy onthe top four DC voltage ranges is+ 0.01 percent of reading + 0.01percent of full scale from + 20 de-grees to + 30 degrees C for 30 daysminimum. To maintain accuracy,it features 1000 megohm imputimpedance on the three most sen-sitive ranges to help eliminateloading errors.

Measuring Ranges

The instrument provides 25measuring ranges. Five DC volt-age ranges and five AC voltageranges permit measurementsfrom 10 microvolts to 1000 volts(500 volts rms maximum on AC).Current measurements (both DCand AC) can be made without theneed for external shunts. Five re-sistance ranges provide readingsfrom 100 milliohms to 13 meg-ohms.

Noise Rejection

A fully floating and guardedinput circuit provides better than100 dB of common mode noise re-jection at all noise frequenciesfrom DC to 1000 Hz. To maintainaccuracy in presence of unwantedripple, or normal mode noise, itcombines the built-in noise rejec-tion characteristics of Dual -Slopeintegration with a full-time noise

...for more details circle 125 on Reader Undo Card

42 ELECTRONIC TECHNICIAN/DEALER, JULY 1975

DELO 'E DIGITAL COLOR

filter to achieve better than 60 dBof rejection at power line frequen-cies.

Portability Design

The unit weighs eight poundsand measures 3'/2 inches high. Itshalf -rack width allows the mul-timeter to be mounted in anystandard instrument rack-singleor two -across. It also is equippedwith a carrying handle and tiltstand for portability. An optionalbattery pack can be purchasedwhich allows approximately sixhours of continuous operation.The batteries are recharged by itsbuilt-in charger when operated byAC power. The battery packmounts inside of the multimeterpackage and includes a conveni-ent self -test feature for monitor-ing the battery condition.

The digital logic and readoutboard swings up to permit accessto components and solder connec-tions. Inter -connections are madethrough plug-in PC connectors.

For use outside of the shop themultimeter may be supplied withaccessories such as snap -off frontand rear covers and a carryingcase with storage compartment forprobes and cables. The price is$675.

TUNER SERVICECORPORATION SUBSTITUNER

Tuner Service Corporation hasrecently added the SUBSTITUN-ER to their growing field ofspecialized equipment.

The instrument has a brushedaluminum base with a flashanodized finish. The power supplyis transformer -powered with a fullwave rectifier circuit. The outputvoltage is regulated by a zenerdiode to provide good performancewhen operated with varying linevoltages.

Tuner Service Corporation's SUBSTITUNER. Formore information about this instrument circle104 on the Reader Service Card.

The unit employs both a detentVHF tuner along with a detentUHF tuner. The VHF tuner has apush to fine tune feature, withmemory allowing the operator togo from channel to channel with-out readjusting the fine tuning.The UHF tuner allows selection ofUHF channels in the same man-ner.

A manual gain control MGC)located on the front panel of theunit controls its gain. An addedfeature is a LED indicator locatedin the upper right hand corner ofits cabinet, whose intensity variesdepending on the adjustment ofthe MGC. As you increase or de-crease the gain, the intensity ofthe indicator varies proportion-ately.

Separate VHF and UHF inputsfacilitate the checking of home an-tenna systems. Separate VHFOUT, Channel 1 IN, and IF OUTconnections facilitate the check-ing of the TV set's tuner for agood/bad condition. A noted safetyfeature is a cover which enclosesthese connections at the rear oftheunit, which must be removed togain access to the phono-jacks.This prevents exposure to the highvoltage present on the phono plugswhen Substituner is connected tohot chassis TV set.

The Substituner comes com-plete with a three foot cable ter-minated within the extension in -line jack, which allows the use of ashort phono-jack cable or a phonoto clip lead cable for versatility.

The IF output frequency is cen-tered around 44 MHz, the stan-dard IF frequency. This allows theunit to be used for signal injectiontests in the majority of TV sets.

Removal of the back protectivecover, which is held in place by twoscrews, is necessary to gain accessto the UHF OUT and CHANNEL1 jacks.

The Substituner can be used tocheck the VHF tuner, UHF tuner,Channel 1 to VHF tuner and theAGC system.

In many cases the receptionmay be as good as, if not betterthan, the original tuner exceptwhere the bandpass is adverselyaffected by the coupling in the IFsection of the receiver. The price is$39.95.

CONVERGENCE GENERATOR

NOW AT A PRICE EVERYONECAN AFFORD

ROCK SOLID PATTERNS

ALL IC COUNTDOWN CIRCUITS

QUARTZ CRYSTAL OSCILLATORS

2 FULL YEARS' WARRANTY

flIGOTAS COLOR ONFRASOR

E .111111111111.1410,111,1111111111,

MODEL $9995SG -200

10 Patterns: Full & Gated Rainbow, 4Crosshatch, 4 Dot, Die,Casted 1/8" AILminum Cue.

111(tf"As MONOome ritirtilaY6W-

OFr

Et NC MODSo ISO

MODEL $7595SG -150

10 Patterns: B&W Bars, White Field, 4Crosshatch, 4 Dot.

MODEL

SG -100

ONLY

$5995

2 Patterns: 20 x 16 Crosshatch, 32Dots, weight only 17 oz.

FULL 15 DAYS MONEYBACK GUARANTEE

SEE YOUR DISTRIBUTOR OR WRITE:

ELENCO ELECTRONICS INC.8144 W. North Ter., Niles, III. 60648312-564-0919 MODEL SO-

D My check or money order enclosed.

0 COD-Add $2.50 mailing & handling.

NAME

ADDRESS

0

CITY STATE ZIP

DISTRIBUTORS' INQUIRIES INVITED

...far more details circle 109 on Reader Service Card


TECHNICAL DIGEST

The material used in this section is selected frominformation supplied through the cooperation of therespective manufacturers or their agencies.

ADMIRALColor TV Chassis M10 - Scan Derived Power Supplies

This chassis employs three scan derived DC powersupplies: 33 volt, 24 volt and 235 volt. The 33 volt and 24volt supplies are protected by F1000, a 1.5 amp fuse.

Positive horizontal pulses from terminal 10 of theflyback transformer are coupled through F1000 to theanodes of D1000 and D1001. The pulse is rectified byD1000, filtered by C102B, C102C and R109, to become theB+ 33 volt supply. Diode D105 is used for protection whichdecouples any negative transient energy to ground. Thisprovides protection to the solid state components connectedto the 33 volt supply.

The same pulse is rectified by D1001 and filtered byC1000, producing a 35 volt supply which is dropped byIC1000 to become the B+ 24 volt supply. Diodes D1002 andD1003 act as protector diodes for transient protection in thesame manner as D105. Further filtering of the B+ 24 voltline is provided by C1001 and C1002. Integrated circuitIC1000, the B+ 24 volt regulator circuit, maintains thissupply at 24 volts during normal load variations.

The third scan derived supply is provided by the D100circuit. A positive horizontal pulse from terminal six of theflyback is coupled to D100 by R101. This supply is unique inthat the horizontal pulse is "stacked" on the B+ 120 voltsupply from the power supply board and therefore, only

Patent 3,778,713

The Wayne Model WT2A

!makes YOU moneyssaves much timemakes trouble-shooting easierA new concept in transistor testingbased on proven methods of circuitanalysis. A current limited AC volt-

age is applied to each semiconductorjunction under test. The resulting DC

voltage is monitored while the rec-tifying junction is passing normal

rated current. Abnormalities areeasily identified.

Indicates PNP or NPN Measures relative gain

Test leads applied without prior basing knowledge Locates base and collector during test

Indicates silicon or germanium Indicates transistor non -linearity

In -circuit tests with shunt impedancedown to THREE ohms

Performs all of above and more in less thanten seconds

WfkflELECTRONICS

5412 Nordling St./Houston. Texas 77022...for more details circle 129 on Reader Service Card


01111011.

SCAN DERIVEDDERIVED POWER SUPPLIES

(24.1 V 4.21110C4T 414,1)

requires a half - wave rectifier to achieve 235 volts of B+.The pulse at the D100 anode is rectified by the diode wherethe derived voltage is added to the B+ 120v referencesupply and becomes the B+ 235 volt source. Diode D104provides transient protection in the same manner as D105,D1002 and D1003. Filtering is provided by C102A, C102Dand R100.

All of the scan derived B+ supplies are dependent oncorrect operation of the power supply board. This is the casebecause the pulse amplitude in the flyback transformer(from which all three derive) is a function of the B+ 120 voltregulated supply as well as proper horizontal circuit opera-tion.

GENERAL ELECTRICColor TV Chassis MC-No Raster, But Sound Normal

If you encounter a no raster problem, but the sound isnormal, and resistor R1103 on the Buffer Module is over-heated or open, inspect the assembly and make the follow-ing changes: 1) Remove the high voltage assembly mount-ing screw and turn the assembly to view the back side.Check for a broken wire to capacitor C1702B (can typeelectrolytic). In early production the wire was stretchedtight and may have been broken in shipment. 2) Replace orredress the wire to provide slack, and resolder to C1702B.3) Replace Resistor R1103 (EP14X63) if overheated oropen. 4) If raster is not restored, check Q1702. If set wasleft on, it may have failed.

MAGNAVOXColor TV Chassis T985/986 - Vertical Jitter

Vertical jitter may occur on some of these portable colorTV chassis. When the amount of jitter varies as the bright-ness is changed, the problem is probably caused by a lowhigh voltage setting or high line voltage. Ensure that thehigh voltage is set to 22 kv for the T985 and 24 kv for theT986 (zero beam current). The condition can be furtherimproved by changing the value of R7 on the 120v regulatormodule. The resistor should be changed from 220 ohms to470 ohms.

A second condition of vertical jitter which is not as-sociated with brightness change may be corrected by add-ing a .1 mfd capacitor across R12 on the Vertical Oscillatormodule.

21 Detent Tuners - Replaceable UHF Pot Strips

The 21 detent tuner is a combination of VHF tuningstrips and UHF potentiometer strips. The UHF strips applyvoltage to a separate varactor UHF tuner. The PN for theUHF strips is 171356-1. If a UHF pot strip becomes defec-tive, it should be replaced in lieu of replacing the completetuner. IN

NEW PRODUCTS

UHF -TO -VHF CONVERTER 135

'the Blonder - Tongue Model UX - 3single - channel UHF - to - VHFcrystal - controlled converter will nowbe avant- hie with a 0.002 percent

crystal in place of the standard 0.005percent crystal. The new crystal,available at an extra charge of $45,improves stability and maintains FCCCATV rules tolerance specifications of25 KHz carrier frequency drift. Theconverter is a solid - state, low - noiseUHF to VHF converter in CATV andMATV systems. Each converter is de-signed for a specific conversion fromone UHF channel to one VHF channel.The circuitry eliminates the possibil-ity of deteriorating the UHF noise fig-ure with the indiscriminate use ofhigh - noise external amplifiers. Inweak - signal areas, a mast - mountedpreamplifier would be used to preservethe best signal - to - noise ratio. Inareas where signals are medium tostrong, the converter input comes di-rectly from the antenna. The unit hasa 75 - ohm input and two 75 - ohm"Loop - Thru" mixing outputs. Thisoutput feature permits low - loss mix-ing of non - adjacent VHF channelsinto head - end amplifiers.

OSCILLOSCOPE 136

A 10 MHz dual channel, generalpurpose portable oscilloscope Model1010A is introduced by BallantineLaboratories, Inc. This all solid - state

,G

instrument provides 5 mV/cm sen-sitibity in two identical input chan-nels over the full bandwidth of DC to10 MHz. In the dual channel display

mode switching from alternate tochopped sweeps is automatically ac-complished by the sweep range switchoperation. The amplitude and sweepranges are fully calibrated. The trig-ger system is flexibile, and provides abright baseline display in the absenceof an input signal. The 3.6 kv ac-celerating voltage on the 8 x 10 cmCRT provides bright easy to readtraces, even at the sweep rate of 100ms/cm. The trigger selection providesmodes optimizing video frame and linesync. Lissajous patterns are quicklyset up by switching into the X - Y modeof ope. .ation. The instrument weighs15 lbs and is priced at $495.

DIGITAL MULTIMETER 137

A portable Digital MultimeterModel IM -2202 is the lowest - priceddigital multimeter Heath has ever of-fered. Included in the unit are fourrechargeable nickel - cadmium bat-teries and a built - in charging circuit.Up to eight hours of continuous opera-tion can be obtained from each chargeor it can operated from 110 to 220 VAC

When necessary. Its 26 ranges includefull scale ranges of 100 mV to 1000volts DC, 100 mV to 750 volts AC, 100µA, to 1000 mA and 100 ohms to 1000kilohms. The 100 percent overrangecapability allows measurements up to1.999 on all ranges except 1000 VDCand 750 VAC, giving full 2 amp or 2megohm capability. Overrange condi-tion is automatically indicated by aflashing "1" display. If a lab standardis used for calibration, DC accuracy is+ 0.2 percent. For AC, accuracy with alab standard 0.2 percent. For AC, ac-curacy with a lab standard is + 0.5percent to 10 KHz. Internal standardssupplied with the kit allow easy fieldcalibration to + 0.5 percent for DC and+ 1 percent for AC. The large 3'/2 -digit display features automatic polar-ity indication and decimal pointplacement. A continuous - rotationrange switch and four pushbuttonfunction switches select any of themeasurement ranges. Price is$179.95.

FM SIGNAL GENERATOR 138

The Model 1012 FM SignalGenerator, introduced by Gaw Co.,Inc., is designed specifically to meetthe requirements of the mobile com-munications industry. It features digi-

Some storessell testequipmentat discountprices.At Fordhamwe discounttheir discountprices.B&K, EICO, RCA, SENCOREFLUKE, HICKOK and LEADER

Complete line of tubes,tools and electronic supplies

FREE CATALOG

FORDHAMRADIO SUPPLY CO., INC.

558 Morris Ave., Bronx, N.Y.Tel: (212) 585-0330


BRAND NEW FROM ENDECO

the solderingiron with alight r41:

i7.\Exclusive new safety lightshows when power is on

MODEL 540S $10.95 NET

Two heats -20w and 40w-to handle any job On -off switch Cool, unbreakable polycar-bonate handle Ironclad tips for longer life

Burn -resistant neoprene cord 81/2" long,

2 oz Converts to a desoldering iron withlow cost attachment Also desoldering ironsand soldering/desoldering kits.

See your distributor or write . .

ectdeCU

5127 EAST 65TH ST.

)enter ise

INDIANAPOLIS,INDIANA 46220PHONE 317/251.1231

corporation...for more details circle 110 on Reader Service Card

JULY 1975. ELECTRONIC TECHNICIAN DEALER 45

tal frequency read - out, eight fre-quency ranges, low frequency outputfor IF alignment, internal/externalmodulation - DC coupled, double -

trace sweep modulation, automaticoutput leveling, external counter tobeyond 20 MHz, electronic fine tuning,double shielding, spectral purity, andless than 100 Hz residual FM. The de-sign of the instrument offers the user afrequency source and a standard of RFvoltage and deviation. The spectralpurity of the unit, in combination withthe frequency counter, give the unitwide application.

FUSED POWER -TAP 139

A new product that greatly simp-lifies power connection for the instal-lation of auto radios, stereos, and otherelectrical appliances is introduced by3B&D Products, Inc. Called "Add - a

fuse," the device has prongs on oneside of an insulating board that snapinto an existing fuse clamp. On theopposite side of the board there are twofuse clamps. One receives the fuse forthe circuit in which Add - a - fuse isplugged, and the other picks up andfuses the hot side for power to the newinstallation. A piece of hookup wire isattached for connection to the ap-pliance. The arrangement makes bothcircuits independently fused.

SWEEP/FUNCTION GENERATOR 140

Dana Exact Electronics, Inc., an-nounces a low cost Sweep/FunctionGenerator with 50 ohm output. TheModel 196A offers sine, triangle,square, pulse, and sweep waveformsover a frequency range of 0.1 Hz to 1MHz. Signal amplitudes of 20 volts p -

p open circuit or 10 volts p - p into a 50ohm load are available. The instru-ment has an internal sweep generatorto sweep the frequency of the maingenerator with a variable sweep widthup to three decades (1000:1). Thesweep rate is adjustable from 1 msec to10 secs. Other features include DCoffset, variable ramp or pulse

waveform with inverting capability,square/pulse risetimes of less than 100nsec, and a separate 1 -TL compatibleoutput with less than 25 nsec risetime.Price $350.

CABLE SHEATH SLITTER 141

P.K. Neuses, Inc., introduced a cableslitter tool for slitting most any type oflarge or small cable jackets. The No.N-62267 slitter has a very sharp,tough hook blade which digs in bet-ween the sheathing and wires andwith the side supports, guarantees theuser an accurate jacket stripping. The

QQ III I^1 1 1 1 111 11111 1141 111 1 1 1 111 111 t 1111114 VIII 11111111111 I 111 1444 # Pig

RAYTHEON

Rapid RebateTake this ad to your participating Raytheon Distributor and receiveA Free Raytheon 6GH8A Receiving Tubewith your purchase of $15.00 or more (dealer cost) of Raytheon RE replacement semiconductors.

Raytheon RE-the only broad line of semiconductorsthat gives you all of these:

individual packaging with replacement cross references printed on the bag comprehensive coverage of both domestic and foreign types listings in Sam's Photofacts® a complete reference guide and catalog

Plus a Rapid RebateOffer expires October 15, 1975. Good at participating distributors, or send proof of purchase to:Raytheon Company, DPO, 4th Ave., Burlington MA 01803

OVOIVIVA151ItIII 111111111

ET -7

I I 1111111111111111111 111111111 11111111111111111111111111



razor sharp hook allows the user to cutinto cable at any point without anyprevious notching, thus avoidinghazard to the inside wires as well ashands. Two screws hold the blade incutting position and also secure anextra blade with the cutting end pro-tected until used. The forked ends ofthe slitter are ductile aluminum, andmay be carefully bent to fit endlesscable sizes. The tool is 6 inches by 11/2inches and weighs only two ounces.

CB SERVICE MONITOR 142

The Lampkin Model 109 CB ServiceMonitor measures and generates RFand audio frequencies, monitorssingle sideband, measures AM andFM modulation, generates CW andAM signals and serves as a digital fre-

quency counter with a range of 50 Hzto 30 MHz. The Model 109 is designedto easily accommodate future growthof CB. For example, if Band E is acti-vated, a 220-230 MHz band and FMdeviation feature can be quickly addedat a nominal cost. As the service shopgrows, up to six other 10 -MHz bands inaddition to CB can be added to allowservicing of marine, aviation, andbusiness frequencies through 512MHz. Other options allow the additionof a frequency error meter, sweep and12 volt DC operation. Other features

include: The ability to measure fre-quencies to accuracies of better than 1part per million; an eight -digit LEDfrequency display; capability of eight10 -MHz bands and measurement ofAM modulation (0-100 percent) andFM modulation (2 KHz and 6 KHzscales). The unit weighs 17 poundsand measures 634 inches high by 17inches wide by 11 inches deep. Basicprice is $1,550.

TRIPOD ROOF TOWER 143

A new 10 footTripod Roof Towerhas been developedby South River. Car-ton packed, thisheavy duty 10 foot,galvanized, rust -resistant, tower isshipped particallydisassembled. It canbe assembled in ashort time with noprevious assemblyexperience. The tow-er, Model HDT-100KD was designed for TV/FM/CBantennas that required un-guyed,roof -top installation. It incorporates aclimable ladder in its design for easein mounting the mast and antenna.This unit includes pitch patches forwatertight leakproof roof mounted in-stallation. Diagonal, torque -buttressing structural members con-tribute to the high strength, lowweight, special design of this unit.Weighing under 28 lbs., this unit hasbeen designed to come within the 108inch dimension limitation imposed byUPS on shipments. A 15 foot ModelHDT-150 tower is also available forUPS shipment within the same di-mensioned carton.0

New 21/2 digit Heathkit DMM-only $7995The new Heathkit IM -1212 Digital Multimeter is the DMM you've beenlooking for...it's easy to read, has built-in calibration standards, serv-ice bench styling, easy assembly...and it's low cost. Four overlappingAC and DC voltage and current ranges and five resistance rangesmake operation fast and easy. Accuracy is very good for a meter inthis price range: 1% on DC volts, 11/2% on AC volts and AC/DC cur-rent, and 2% on resistance. Full scale ranges are: DCV, 2, 20, 200,1000V; ACV, 2, 20, 200, 700V rms (25 Hz to 10 kHz); DC current, 2, 20,200, 2000 mA; AC current, 2, 20, 200, 2000 mA (25 Hz to 10 kHz);Resistance, 200, 2k, 20k, 200k, 2000k ohms. Lighted panel indicatorsshow overrange, positive and negative DC voltages and current. Allsolid-state design uses IC circuitry for clear, non -blinking display withreadout update every 16 msec. and automatic decimal positioning.Overload protected. 120/240 VAC. Also available assembled for only$125*.

See the complete line ofHeathkit instruments inyour FREE Heathkit catalog.

HEATH

SchlumbergerHeath Company,Dept. 24-07Benton Harbor, MI 49022

Please send my 'Tee 1975 Heathkit Catalog.

em

11161A. ORDER PRICES; F.0.. FACTORY.LN cEs a SPEC, iCrpONS SOW,' TO CHANGE WITHOUT 140/ICE.

ZIP

1

TE-326.


.:ULY 1975. ELECTRONIC TECHNICIAN/DEALER 47

CLASSIFIEDRATES. 35v per word. 450 per word Bold FaceType. Add $3.00 if you wish Box Number. Minimum$10.00 charge. Classified Display Rate billed$40.00 per inch, 1 inch minimum. Remittance mustaccompany order. Mail ad copy to: Roz Markhouse,ET/D, 757 3rd Ave., N.Y., N.Y. 10017.

Business Opportunities

OWN YOUR OWN PICTURETUBE REBUILDING BUSINESS

With Lakeside Industries rebuilding equipment you canrebuild any picture tube.

For complete details sendname address zip code toLAKESIDE INDUSTRIES3520 W Fullerton An.Chicago. III 60647Phone 312 342,3399

Improve sagging sales with high profit -quick turnover CB equipment. Write fordealer application. Wheeler -Dealer Elec-tronics, Dept. ET/D, Bascom, Florida32423.

For Sale

RADIO & T.V. TUBES - 36 cents each.Send for free Catalog. Cornell, 4215-17University, San Diego, Calif. 92105.

CANADIANS SAVE BIG MONEY!SURPLUS, CLEAROUTS AND BANK-RUPTCY INVENTORIES. HIFI ANDPARTS. CATALOGS $1.00. ETCO-DELECTRONICS. Box 741, MONTREALH3C 2V2.

HARD -TO -FIND TV & RADIO PARTSNEW AND USED. ASK ANYWAY CMC4329-4 WOODMAN, SHERMAN OAKS,CA. 91423

FOR SALE

Established Radio & TV Sales and servicein Sunny Arizona. Retiring. P.O. Box 236,Mesa, Arizona 85201

REBUILD PICTURE TUBES. We sell new& used equipment with complete instruc-tions in our plant. We buy used equipment.Factory Outlet, 951 E. Hudson St., Colum-bus, OH 43211 614-263-0645.

CHEMTRONICS CHEMICALS* WhalSoldering Irons and Heat Guns* Transis-tors, Diodes, Resistors, etc. For the tech-nician or the do it yourselfer. DistributorPrices. Send 25(t for catalogue Box 100ETD

TUBES receiving, factory boxed, lowprices, free price list. Transleteronic, Inc.1365 39th St., Brooklyn, N.Y. 11218A,Telephone; 212-633-2800.

FOR SALE -RIDERS MANUALS 23 Radio,21 TV, Vol 1 Sams Best offer lot over $7.50@ LYSTEMS, 106 Eddy, Dix Hills, NY11746

For Sale: Howard W. Sams Photofacts,complete set -folder #14041402. In fourfiling cabinets, complete price $1400.00.Valley TV & Appliance, 29465 ChualarCyn. Rd., Chualar, Calif. 93925.

TV & RADIO TUBES .36¢ EA!! Send forfree color parts catalog Your order free ifnot shipped in 24 hours. Cornell Elec-tronics 4215-17 University San DiegoCalifornia 92105

UNUSUAL SURPLUS, CLOSEOUTSAND PARTS CATALOG. RUSH $1ETCO-4 ELECTRONICS. Box 741,MONTREAL H3C2V2.

BURGLAR alarm police dialing unit au-tomatically calls police or any number.$29.95. Easy to program and easy to in-stall. Free literature. S&S Systems, Box12375 E, North Kansas City, Mo. 64116

For Sale: Used picture tube rebuildingequipment, complete -and equipment forlaminating and delaminating face plates,and supplies. Escom Pack Sr., PaverBarnes Road, Marysville, Ohio 43040 (513)642-7161

L

send a message......write here.

1. Number of insertions: (circle) 1 2 3 6 122. Start with (month) issue (Copy must be in by 1st of month preceding)3. Amount enclosed: $PAYMENT MUST ACCOMPANY ORDER WE'LL BILL RATED FIRMS NO AGENCY COMMISSION

NAME COMPANY

STREET

CITY STATE ZIP

MAIL COPY FOR AD(S) TO: ROZ MARKHOUSE, Electronic Technician/Dealer, 757 Third Ave., New York, N.Y. 10017

RATES: 35v per word; 45v per word Bold Face Type. Add $3.00 if you wish Box Number.Minimum $10.00 charge. Classified Display Rate billed $40.00 per inch, 1 inchminimum.

ELECTRONICTECHNICIAN/DEALER CLASSIFIED


Construction PlansConstruction Plans Repair your own TV. Valuable Information

$2.00. TIP$ Bruce, Miss. 38915.

DIGITAL CIRCUIT plans are availablefor; Automatic 125 Meg. freq. counter withmany features, Delux Logic Probe withpulse indicator, Digital Clock 6 digit read-out, 60 Hz. time base for all digital clocks;Digital tachometer. Plans $2.50 each,Boards available for all plans, drilled,etched and plated, Com-Tronics, 144Cloverside Ct., Buffalo, N.Y. 14224. 7/75

YOU'REWHISTLINGIN THEDARK,,,

cirZI J44

IF YOUTHINKHEART ATTACKAND STROKEHIT ONLY THEOTHER FELLOWSFAMILY.

Help yourHeart...Help yourHeart Fund J)

n. .h, PsNuFn

Complete Construction Plans - TELE-PHONE: Answering Device, AutomaticDialer, "Black Boxes," Call Diverter, CallLimiter, Conference Bridge, Central DialExchange, Melodic Ringing, Recorder -Actuator, Remote Control, Schematics,Speakerphone, Telelink Burglar Alarm,Voice Schrambler, $3.00 each. ELEC-TRONIC: Biofeedback Conditioner, Hor-ticulture Stimulator, Multifrequency En-coder Network (Speeds telephone calling100%!). $5.00 each. ONE YEAR SUB-SCRIPTION to Telephone Electronics Line(TEL) $6.00. "The Legal Aspects of Inter-connection" book, $29.95. All of the con-struction plans above plus a one year sub-scription to TEL $29.95. TELETRONICSCOMPANY OF AMERICA, 22035 Bur-bank Blvd., Suite 122, Woodland Hills,Calif. 91364.

WHY BUY A CRT RESTORER? If youhave a B&K 465 or 466 rejuvenator, con-vert it to a CRT Restorer. For informationJames R. Chancellor, 1708 Edgerly Av-enue, Albany, GA 31707

COMPLETEComoraucnom NAM

TELEPHONE PLANS. SI mesa.kmoenm Drain. Amoomite Dialer. "Illnel Roe". 1.1111 %eerier. Call broodlooleteete Bridge. Control Nal Exchange. Melodic Losing Generator.Recorder Arius, Rearm Control. Sebeinaties, Spealtrabone. Tekliu1Burglar Maim. fence krambkr. Dial/Tom Comm, Tom/Dial Convener

NISI.. PLANS: SA .n eadiBiofeedback Ismlitioort. Alshirfresoemy Encoder Seined. 110fIN1111tt

Stuadator. Dodecahedron Smoker Eatleasme. Photograpluc Pinhole Camera

ALL OF THIPPPPp FRICTION PLANS ABOVE, S14.g5 ASSAILED.

s" LEARN THE SECRETS tia

'IS OF YOUR TELEPHONEloom Eltdrillaks

der ftodeted I.,. bellied that [tiepin. dial, Nee diti cankm, the trick. On idealism oak Get the inside oar, of idealismsee.,- tiro said. nod flan, and remain up to date vital femme,soils lie telephone missed TELEPHONE ELECTRONICS LINEnoil.cation demeord lot Om telephone e.Ilnv Moor Piteek. and

dmrinevid ..maiming 'toddling article, shich eller a sealti ofInd .nintrnat...n Technical them, n ale diAcmaed, dam, the [album ado,

Current News Items Code NumbersIllustrations Games Facts PlansProjects History Comics StoriesFacts prieviously Tel. Co. confiden-

tial is now published in TELLOm year mined/tin ram Anted Staid Soo. Comdian A foreign Soo

ALL OF THE CONSTILI T ION PI ANA ABOVE PUS A ONE TEAR SLI-M RIPTION TO TEUPHOAt F I II I Roma UNE, 329.9% AIRMAILED.

TIE LEGAL REMOTEAF IIIITERCOMMECT1ON

V. 11 RS Fillip

The complete reference book to yourLEGAL RIGHTS as a telephone sub-scriber. Study toll evasion, tariffs,wiretapping, customer provided equip-

ment, and many more!AIL Of THE CONSTRICTION PUNS 1501E AND A 11.11141 SEBSCRIPTIONTO TEL PU S "THE LEGAL ASPECTS Of lATFRLONSII SAO. ASSAILED.

TCRTELETRONICSCOMPANY AJVIERICAe2035 BURBANK BLVD.,WOODLAND HILLS CA 91364 US%

Educational Courses

REPAIR TV TUNERS -High Earnings;Complete Course Details, 12 Repair Tricks,Many Plans, Two Lessons, all for $2. Re-fundable. Frank Bocek, Box 3236, Ent.,Redding, CA 96001.

EDUCATIONUNDERSTAND digital electronics-calculators, microprocessors, clocks. Newprogrammed learning courses. Design ofDigital Systems, 6 volumes, only $14.90.Digital Computer Logic, 4 volumes, $9.90.Both $19.90. Unconditional refund if dis-satisfied. CAMBRIDGE LEARNING EN-TERPRISES, Box 428, FDR Station, NewYork, NY 10022

BUILD THAT ELECTRONIC ORGANYOU ALWAYS WANTED AT A PRICEYOU CAN AFFORD. Third edition of "Or-gan Builder's Guide" pictured product kitline, circuits, block diagrams, designrationale using IC divider and independentgenerators with diode keying. $3.00 post-paid. Also, free brochure on keyboards.DEVTRONIX ORGAN PRODUCTS, Dept.A., 5872 Amapola Dr., San Jose, CA. 95129

How to save money on tuner repairs. In-formation $2.00 TIP$ Bruce, Miss. 38915

Manuals and Periodicals

HEAR POLICE/FIRE Dispatchers! Cata-log shows exclusive official directories of"Confidential" channels, Send self-addressed stamped envelope. Dealerswanted. Communications, Box 56 -ET,Commack, NY 11725

NEW CANADIAN MAGAZINE. "ELEC-TRONICS WORKSHOP". $5.00 YEARLY.SAMPLE ETCO-C, Box 741MONTREAL H3C2V2.

Wanted

WANTED: PICTURE TUBE REBUILD-ING EQUIPMENT used or new..Call orwrite Atoll TV, 6425 W. Irving Park,Chicago, Illinois 60634. (312) 545-6667.Evenings until 11 PM call (312) 235-0420

Want Schematic for Korvettes TV set XAMModel 1269 and need part number for yokeand horiz. trans. Arthur R. Vickery, TheMusic Shop, 548 Main St., Torrington,Conn. 06790.

ELECTRONIC

TECHNICIAN/DEALERis not responsible forany of the items,plans, courses orquality of productsoffered through ourclassified section.


DIGITAL

PERFORMANCE

YOU CAN

RELY ON.

The Hickok Model 334 DMM isa rugged, non -temperamental,hardworking tool that's easy touse and easy on your eyes.Hickok has established a uniquereputation in digital electronicsduring the past 10 years. TheModel 334 is another exampleof our engineering expertise -an economical lab qualityinstrument with exceptionaldurability and accuracy. Easy reading, green

fluorescent display 31/2 digit - auto polarity 26 ranges including 200 mV

AC & DC ranges Fast response -

2.5 readings/sec

Basic Accuracies (% of reading)DC Volts; ±0.2% (±0.5% on 200V,

1200V ranges)AC Volts; ±0.5% (±2.0% on

200 mV, 2V ranges)OHMS; ±0.5%DC Current; ±1.5%AC Current; ±2.0%

Ask to see the Model 334 at yourHickok distributor. It's a nocompromise DMM at a priceyou can afford.

$22900

HICKOKthe value innovatorINSTRUMENTATION & CONTROLS DIVISIONTHE HICKOK ELECTRICAL INSTRUMENT CO.10514 Dupont Avenue Cleveland. Ohio 44108(216) 541-8060 TWX: 810-421-8286

...for more details circle 115 on Reader Service Card50 / ELECTRONIC TECHNICIAN/DEALER. JULY 1975

READER

SERVICE INDEX

ADVERTISER'S INDEX

131 AMP Special Industries 50

132 Astatic Corp. 39

105 Blonder -Tongue Laboratories ..8

106 EICO Electronic Instruments

Co 4

107 Electronic Book Club 16-19

108 Electronic Devices 50

109 Elenco Electronics 43

110 Enterprise Development

Corp. 45

111 Fluke Manufacturing, John 33

112 Fluke Manufacturing, John 33

133 Ford Motor Co 26-27

113 Fordham Radio Supply Co. ...45

GTE Sylvania, Consumer

Renewal

General Electric Co., Tube

Div. 23, 32

114 Heath Co, The 47

134 Hewlett Packard 38

115 Hickok Electrical Instrument

Co. 50

116 Leader Instruments Corp. 6

117 Mountain West Alarm

Supply Co. 50

118 Oelrich Publications 50

119 PTS Electronics Cover 2

Quasar Electronics Corp 31

120 Quietrole Co. 4

121 RCA Solid State 5

122 Raytheon Co., Receiving

Tubes 46

123 Simpson Electric Co 3

124 Sprague Products Co. 7

125 T & T Sales Co 42

126 Tech Spray 41

127 Triplett Corp. Cover 4

128 Tuner Service Corp 11

129 Wayne Electronics 44

130 Weller-Xcelite Electronics

Div. Cover 3

FREE FREEto introduce you to

SOLID STATE

REPLACEMENT

RECTIFIER rijiTUBES

Solid state rectifier tube replacementsoffer many servicing and profit advan-tages: 6 Solid -Tube Ca types replaceup to 37 different high voltagevacuum tubes. They're somethingyour customers will appreciate.

' Eliminates need to replace defectivefilament winding on flyback. NoX-radiation. Reduces fire hazards. No filaments to fail. Reliable. Solidstate. Faster warm-up for picture. Modernizes older sets. Much higherprofit than vacuum tubes.

Get the full story on EDI Solid -Tubes', rectifiers, and get a freeSilicon Focus Rectifier too, just byasking -on your letterhead or businesscard, please.

Am ELECTRONICDEVICES, INC.

21 Gray Oaks Ave.,jYonkers, N.Y. 10710Telephone 914-965-4400

...tor more details circle 108 on Reader Service Card

0011111 UY AMPCABLE TIES

BY MAIL!Up to twice as strong. Self-locking.Nylon with dual stainless -steel pawls.Four sizes. Various colors. Send $1.00for generous trial package 25 ties.

We'll include new AMP mail-ordercatalog free. Describes hundreds ofelectrical items for servicemen. Orderfrom: Ties, Dept. 3006,

AMP Special Industries,Valley Forge, PA 19482.

AMP Offer expires

SPECIAL Sept. 1, 1975

INDUSTRIESD,vision of AMP Products Corporation Valley Forge. Pa

.. for more details circle 131 on Reader Service Card

IT'S NO PUZZLETO ORDER

OELRICH SERVICE FORMSFOR TV.I1A010 8 2 WAY RADIO SERVICE LEGAL FORMS FOR CALIF. FLA.UTAH NOW AT YOUR PARTS JOBBER OR WRITE FOR CATALOG AM

OELRICH PUBLICATIONS4040 N NASHVILLE AVE CHICAGO. ILLINOIS 00634...for more details circle 1111 on Reader Service Card

FREE ALARM CATALOGHuge selection of burglar & fire sys-tems. supplies. Motion detectors, in-frared beams: controls, door switches,bells, sirens. 500 items, 99 pp. packedwith technical details. notes.

(Outside U.S.. send $1.00.10 mountain west alarm4215 n. 16th st., phoenix, az. 85016


@ PO, at produttoo

ELECTRONICTECHNICIAN/DEALER

17-#=-6COMPLETE MANUFACTURERS' CIRCUIT DIAGRAMSAND TECHNICAL INFORMATION FOR 5 NEW SETS

ADMIRALColor TV Chassis 4M10

ADMIRALTV Chassis TL6

MAGNAVOX 1595Color TV Chassis T995

MOABv IONS

fCROlboI Hy

:04eCTTemu NI 1135

31101O, Mr

rot '(IIIa,11-4

01

1434-4

GOO

0

ALC

tt c.31.62w..0I's" I

Ng 0110 Ma 15 SII IMO 10AVM IN I fel 01 SIR.

1594 PANASONIC 1596Color TV Model CT -324

1593 TRAV-LER 1597TV Chassis TR2-1A/2A

R339O /GC DELAYet

E

0306.14,

L 30 2 El

c4 OE a

L301

T201

1202

0 14

IC201

1303

C

EDO0301

0302

0407 0403

EAR 0405 etC

E

7

lOi

L201 oCR3020C307

DeIf g PO/11 7"OOOr 1411110,0

BLB31.4°,*or: )0305TRAP

INICR402E

C

00404C /TE

144114040406 VERTICALSIZE

V1305

0 0304

CR401

0402B

SAFETY NOTICETHE DESIGN OF THIS RECEIVER CONTAINS MANY CIRCUITS ARO COMPONENTS

INCLUDED SPECIFICALLY FOR SAFETY PURPOSES FOR CONTINUED PROTECTION.

NO CHANGES SHOULD NE MADE 70 THE ORIGINAL DESIGN REPLACEMENT PARTS

MUST SE IDENTICAL TO THOSE USED IN THE ORIGINAL CIRCUIT SERVICE SHOULD

NE PERFORMED BY QUALIFIED PERSONNEL ONLY

1341510

oaf 5%

4140

0303

578185-12ACC DELAY

I L. j

1.10 Fusel

144321 1

NMOW

501(111IK 1010

11313101 0ALIA$1329A11.,0% CAPICITANCE 114.0(S I 01 413111 111 ill P1 CAP1C111110 411151E53 !NAN 111( II113131110 non OF COILS LESS NAN IA IS LOT 51011 O,2 111BAIES 336133 moo000132 110 0110011 1010. OC 40i TICS '4(I '* IRS' 'O nee I ;e1310 I 03 ALNICO 1441101113 at 0 1 11111r -T 'III. 11 1301 AC 01( 040N AT VOT 0001010C ON C1111111101 01 TEST (011,1101 /NO PANTS IOLEIANCES 1111(11( 11111 1/3 /11311(3 111 111101E0 000113111111 1111 II 31(111 IS 31001 1111131. 10111114 1101 WO 10.31031 IS 31011 011110111 ROM 1111-311111 1011103 MENN 11001 4111 3111111 (III 111(111 101111/5 5110110. 1101.111( C011101 AI 111101101,1110111/0 AID W0151 01111101311 1311101 Ail 011E1 60111013 IN IOW OP(111111 P031141. 011-31011 000103 1110 MUM 1101 VIN 11110111111011131 S1t111 000111111 1 TO 1 10(10 ICC II MI $$$$$ SI LII 1110003 30111(35 Y 1311131.TIAISIS101 011101,10 11010 AAAAA ( TO 11511111$1015. 00 I01 Oil 11003 100 10 3111101 3111310 00 NOT 101 SIT 01 110 111131310101,1412131 01112303 1E100(0 01 015010(11(11 433 310f10110 1110(111 101110111i MIT 1011111 CONPONENI 1/11111115 01 f0

001311 61101110. 00 1101 Of 11 01011111 01110E1 10 10130110 1031/1101111, US( VIII II 11100 1110 01 111611/11,ICC 611111010 III 0131111 (10011 111 ACC 0011103 11100 10.111311111 3 1111010 1(1(1 TO 30110 111113.

1EC15311, 10 (131311 ICC 11411311101, Hill 10101 P0311101 30 nal 30111103 CAI 1E 1001(0 TO 133 flACt 01131103 301113. Ail 131(1(113 1110 MTN 1 nit .100 OSCIWISCOPE SON( 30111011I01 Will Ili 10100 11 11011/. 110001113 me/13114 111101 11110PIS3 (01111111(11.

4011101101 NOT 103111[24 01 P1(613101111(0 313111

MOILVS( 130111101 1111131011111 11E1 31101013 1111011W 1161 100104 CON ON CIOUND 11-1

10110 VII 3331 PAU Id AS 01131113r/(5/$20/1 go lf / 40010 07 'WOO ICI Neff pm,

KYR 3111

RUN CHANGES I. 4)IC( C

TERMINAL CRIS OF

TRANSISTORS

E C

1411/0

4)1r/OP NW.

134

9% ACC MAT

,113;,100

1111

III,

150414

111,

1R407VERTICALHOLD

wag "NI 1SOTTO, MI 0111101111111011041

12T]

1111 14.3nL 2-8.1 .1 OE

C11401 /Jr

101 [LAI

C B

0401

oCR601

0,310t

578139-4 578138-4is 1ST IF cm 2ND IF

0501Flf_,YR.5%

0302 rIMF

401

1.7

It11114

5I A.1/4115%

C5011 0101I13

III 105% 5%

13 lirEt] ._7-10:!:

1 lir

....1' III.'"'''

.0A103 I:=1::::144 2101U

LV....111122 11I/11 N

FED II25%

1101

T57111.4V 1,1,1

1

3c:FM71,1.001519.3!0".

H0,14,

I/41 "578184-121;1:- -T-Va 578191-12

SYNC SEP 1_11%VERT OSC0401 0102

60(4

0.

Ir

I h

cm

T:47

F6315A

CR602

0502 C

-cCR502o-

CR501

TT 0501JLC

578191-12 NgvIDEOCEI 1ST VIDEO 0135% 710

13011 0304 1701303 0/301 oar 3101141ss

UL501HORIZONTALHOLD

Ira4105%

Ir

111

.170

001 1401

444411

us.

MXGTE C315 1141C11 /1/1

050 11451105,0My. Fr

710,4r578185-12

MT KatJ%=I !Ornate', PM

1145V1,1/11

IYERIKC130211310-1

1144 410

10111folTlir' 0131571.

011/

r 114nANV11,5IT VA

POWER RECT

I145 1101 50T0011110,FOS( 9.

L

2235034

+F-1ell* 003 1230/

/A, OH INjoy. CCM . C502 ,,,

150412 1)C".'"' ,1501 C11501T *01 _dsoill. am,

Mil 11X111-1 05001 ad/

02.4.-014-0 MsNow RASE 7". 10%

C303. Att Du 0041500,10% 1502 SOY

40 0901 401.1/41 4-4-

,13 1504 150311 111

11.0113

JL ION

1354110

II

/II

11,1 - Off Mg1 31 L

";;;-.1. 6140141114.

loot0 (II

1301INN

001

II

CND

3E= W41200= 5" --

Miff

P 114154l

tI tit +

410

T-H-R3%

op. 10111

1593ADMIRALTV Chassis TL6

JULY 1975SYMBOL DESCRIPTION ADMIRAL PART NO.

R333 - 100K, brdeness Control 75A1-212R339 - 400 ohm AGC delay 75A101-35L201 - cod. 4.5MHz 72A317-1L301 - coil. 47 2SPAH2 trap 72A415-8L306 - coil, det. 72A316-8L310 - coil, 4.5MHz. trap 72A317-9L501 - coil. honz. lock 94A480-1T201 - xformer, audio output 79A172-1T401 - yoke deflect T2L6 94A372-3T401 - yoke deflect T3L6 93A372-4T501 - xformer, honz. drive 72A417-1T503 - xformer, honz. output 79A166-4R203 - 25K, vol control w/Sw 75A1-225R326 - 500 ohm, contrast control 75A1-211R333 - 100K, bnteness control 75A1-212R339 - 4000, AGC delay 75A101-35R411 - 2 M, vert size 75A101-61R407 - 1.2 M. vent hold 75A191-3F601 - fuse, 1.5a 84A7-15

PWS 5559-5

578192-10

*I IsmAI/4W

1100 OUTPUT

1700 400

11,01

12/00

04

IN"1707'

.13011111Whieliii

IM11

-101'--.6..m-x/01.11110 Mt

4.560, 2 It" 578211-8VIDEO 000111

0305

KatSist cpp

005

'T1.21

611071

T1 H

1300

1101151

r1 004031 fIf, 410,40111040, 403100014.1

gyme4 11 MI III /A

12V8JP411 1111 111 0

4141ci , 11

11r

11i23/111

44/4

÷ la yr.

iSit

11,51 V0:;. 15,11CONTRAST 11.3,

1311 OD,162161TNESSSoo!

3

4-

scpi.4-." 110327031

03523: repo, 4'05' 1 51100VIII

11% ATATOTTOTLIT_EA

14/1171

'AM

71,

(4,07,578184-120400vER 8101(106

1401110s5%

VERT

NOLO

11E1

-OffC404

I=22

300 -

VERT

SIZE

F. 578191-12VERT BuFFER

4412 0403E -a,, 3.Ir Cool

TuT1410 =TOO

402 11130001 1413

03C la

0 :: 041 1411-001. 300Iv% oy

CIO/

/1/559011,41

578191-12qv DRIVER

0404ce..

reztH

-r0101

1411004

N77

vERT

OftolVE05R2:i0,060:40114;

Fs(---"v

578191-1211.10,15

ITMIL.0.44.k.,,, 010 NM / vir./101,/ 510151

578185_12 ni:11'1171:

001

00

0502(

I :MrCO11Th

dII

II Ill1701

1 1r

411

N°112

De,RIaV,Ellzmosicrouncoe

501781210300-p5u1or;"[t "1:7;4,

578191-12 1401111 OSC 0501no.

TOlf

1,4150, 00.10

a ,0501 'S. 3A411 (0

0'11 /0111I .521 mt. .

Sr 11 /91NIET 05,4CO

01

301TO% 1313 4511 1641 1511 2101

1.54 Eye 131 1711 ITC 1521

(Ho, 1,P,SAM 1.01

IAN311

-578188-12A((T 0TPUT

0107 Ito 1.1

124.5%. 11III It

578214-12VENT OUTPUT

0404

RIO.3111

TI If03112

15III?

14421

1115%

1124IN3%IHI

Cu>ort

3.500oat

TO%AA

TOMR 1- -/101113

0111 III WOon WU 941

500 50r ,

el

WS " OK 1201

W,C12

I140

14011TO11

VERT

SON T

Is. .3114 1611.1111

csot

mat.to.71

13lool,

I005 11013401504

.;151. 41.0*,/401 MO Nil11 11 11

1121

t4

It PICTURE

TUBE

V301

T 'Pt ItHIV 11.1,71,11Al II MI II

715I1 II JII /INKIP COON /I'Iii -11 ag0

COPYRIGHT 1975 BY ELECTRONIC TECHNICIAN/DEALER 1 EAST FIRST STREET. DULUTH. MINNESOTA 55802

1594

00111 411101 0115315

17/117L1/411

0011

Keg

ADMIRALColor TV Chassis4M10

JULY 1975

1711 1711

INI.e-MMP-117 30

1000

ELECTRONIC IrAG:6.4COMPLETE MANUFACTURERS' CIRCUIT DIAGRAMSAND TECHNICAL INFORMATION FOR 5 NEW SETS

II MI,ruir NH MOOSWV, 201713417.

1703'1

0110211.01

I 117:

u'eN-1111,

1

1 WV

r KC 11501

L Ell 07159711110 100101 "440 7

0701IRII

.717411vo

NCI 10707

111

la

,,÷-1w;/--1,, '51E1249 -4m:578141-4

42011 71ST IF

1,11.1%

:02C4tot1d21.1

22

1%

1210111.1/411

111.1011

tIL47,04

1201 C201

;11 SS 1/41

51

ISOIII

Va

1/11015

1/11

-

7111I

t /r 11 17j.$11705 CUE :1/111

LA $'441 r ci., =CM 1700i11411 v411 1041500 I 21

9-14 i"

weAR 1510

till

1731.1%1734

J Z 4/.1%

- - -1717

578249-4 OR

578141-4

C241

1500

14 INCAI VIC:,

MODEL FINISH CRT TUNER CLUSTER VHF UHF CHASSIS

19C618 Walnut 19VEJTCO2

NC2800-1 94A492-2 94A462-1

or

94A466-1

4M10N C2808-1 94A493-2

NC2809-1 94A507-2

578249-4 OR-

It12.00,M300, M400, M500140-4- 578141- 4 SMALL SIGNAL BOARD 4.5 1111 4MP

00:IA.

AFC /AF

578134.12

r 12500

0205 '"/pi 1017

17 130"

}11711

j C,2i5

1.12400141

14

IWO

1)1

5I%

4 IO

160('I csrt'

7041502 4501

05

M rAMP

I:4 A121

1s

11,0201

o3.; 052108214

2-4111 IF

lion G'1

ND 1F

4, 1717I

4t,,4 c1"4a 12,5

. :12:AVF.7

C.sc.2,1111

41

C5;0111 A CI ,11,1r-Esif DELAY L.,2 101 ;-

40

+-N;

on 578175.1253,17

R" CTIti

41

J

111 ACC DELAY

0305

13t10.110001.K01

two.do

'0578196.10PASS

1110 TRANSISTOR

it 0102

141

O 9O 44E11110 111111 107111

HI

vN

1'°1

1151:

570196.10PASS

TRANSISTOR

mos 0101

000.3151 Ir /, r

IN;

1 11141 171

171 UP 1751

15001

1705SRO 11

17;1Ill

C221

Jr-11

3% Sa

%1;ors

ss

11701NON

'T11+1 To

1:230130 on,

% 411141

0701

3%

0121Cf0oN cn 12075, 170 J1021

1'11

5%I II II .2214711 1211 1211

'

ItI1410745

171 1

Ts°.

31 11405%

1,50,01ii I

113%

;50010000:Nit/

11 11:,;1:14*

+--11 ", , _,t4o, Fig,,,

"

44.10°

:OMErr _

1400 4114

1104 nos ems"1

:1,: If."

till

Ita

112

l2121(123

1111111

1%1/41

" 17

m ytom

ro °-t, 1101 MINOP

411 rill

171-1".4/1.711111"..,

1100 111

21011.44151CCH

04 }. MO/110414O

01 I1100 1100

144-` AVM 11111 4111 41 41

'40 I 1102 1,L101111 OF

IIIMI01-kq""fft 04042ornirrizii

jWWI 717 COMM II

$177 MK

10, YY ""'34101000

1134

VOLT

SIZE

1150111

101

0100

1100

qrum

578201-14 totIrySYNC. IN 0600 ÷-11.

578134-12 NrCLAMP0606

Nil1 1.

578202-13 1$OSC 0601 174."..+

/-JI -

1?arog=

+-4"1.44 ?

1114( VERTx010

4t%

Cs eit*out .0, PASS DRIVER fie

WV i ... 0900 rs'"' ° is At!. 120 401010X

.......--

1101 Or1141121 rt.

.111c.5,

5% 1 3501

1101

el NI /MI1

...114

Pt;"MC1111

DOI ,,,,,, C105

OIT 4101 NIna---, 1/41 500

40--41(-44.Pr IN44,, 13040 .,..., 101

I/4 1/411

If My

0 0 11.

cel.-m;;;It 00,1

,0 03 1107

:T1K

057

13111

1.1

57818112ACC REC . 0304

J

578182-12 vEMIT TER FOLLOWER "i*0203 tem!,,rit

n i" o 578182-12

11

WOVIDEO I CHRONA 4/0

AMP 0204 We TILT

f7Til,1714-1

0.3Yr W Jr 1401 -L:r :: 4:1

171

WON

+ pa t 1311 -ft -4.0cot'T

5, "4 Tilf"i241

ir41

11,2 578182-12 '0NCI 1 111

ACC INVERTER 1 STN

11171 I 578182-12DRIVER,

'Illi .,

UN NOISE CATEC4 "'

':hi '1: ,

15.4 ,. . '- ',1/41

OJOr

ft % 1.7.1--'

N ,,,, 41''la

77T 1 54112.1+)1-- SIN WINO

Irr 1W 1141/150. T ."'

I{ 11115

ACC

1101771

5.11

.1578159-12ACC CATE

0303

1101 : 0306/311/311 '.0Wit

1011 II

111

I

C:11:',': .4,0,10;

.511:"

1

1111

17_0.1_

3 17

111,,

115s.,7

111,501

4.1111-"2-

4(,111 1477 .4414--;

110 _xI Y1 1/11 0141.1211.

`1';3401too .so,

er

V4

4,0

105fro

111/

-1

1403t./NC

of 0

Ion

CurN CANN

0-

AC100 141

001011411IV

111:15007/ / Jr e

1

-L- rr 1113It

SS

NY

/

7

3%

441PO

5%

N14

1444 044343

2

1417ti

C447

1401 Ca

1 11 21

5% 5%1

1412I

C171

420.5%

+-3

578137-12 q,, 71:PULSE FORM /10 ) "°1

0400( to 14751/0

2 21

578200.12PULSE FORM

to30 0401

MI can

C470

518135-1

15,22.4taco. Dui

244'

1.405

140;lp

1411

4/05.1141

1423111.5%

t431 1454 1241Au

1/111311

04,1: -1141

rfa l2.

1171

157

7711/411

5%

011

MI01M/1.11

5%

,1445$1 NM

1/411SS

1444 011$

16 110

15 ILL1,, 0

C4/11(1 1444

ge,I7 0,4211. till10111.210' 041WO

,F-11 II -A., 1441

04,1 4/0 /Mt

1402 C421IOW II

110 1 LS%

01

01

0007

Ird

zar578207-8

M900 POWER SUPPLY]

tor

5

578195.10AUDIO OUTPUT

0100

O,1100.

1170

14;00 rls.17.41SRAM (1111

3014101 001111111

uS10 01711010 41115.515

10011.21 r,-101 kV Kt 01,05.41 NICK IMMO AIMeell KOOK AI AM (00111 .4m14 K0055 .

5%

14041.31.51. COLOR

ICLLEoa 411

4,

IMO

0000

;.,

1103. 1 1.1/71

11/1-

415410151241 MST1101 11411

III'

ISO,

578241-14 co

,, .578219-14 I2-2E DRIVER C404

060401." --

*75 74,

518253- 4 HuIMP 54

96025%

C1010105

11507NOT

131/1 31

21:-";1

0401 1107

11014.2

N

;z1 C421501

T ;0

101111

0121

0'

578240-1410578220-14H

3/4 DRIVER 9i0Orr 0605

518134.12PRE DRIVER

0603

14:: 4

13I

1,

11-4.578251-14 _2,

v2

M60010578206-14

i v r -v-, VERTICAL jVERT. OUTPUT ,

0106r-,4,_,,, ,c.

o,,,,,, , PICO

wijil1

IgIs.g

1441JI00

578250-14oR 518205-14

VERT OUTPUT0105

1110

rY

47

tor

1101

404

,V2tf_A_, 1700rr Mr

578159-12 4141,1ST VIDEO SIP 1' 2.2

0700 "i'LQIN

NOS

1%

578182-12210 VIDEO AMP

Trot,,gfa

110501,1

39.

518182-12BLABBER

cm 07 to

loom

f_41,_,+.7.o 4.

P41

I/41701

BRUTLIMIT I, crcr

1-518b7712VIDEO

71103.fr

3RD

1101.

3%

578182-12BRIGHTNESS

LIMITER

OTllr

(g)

$1,

1/11110

.1D2

Agri IX1U\ VIDEO AMP

070 2

100 0

vo 0-4

.1112VOW

Col .1E1, yx,721 01.0

1105

111011 ; """ 11 5%MOS*,

s 2

1194

I

21,7101firA)A

-17A r% /7/771 ra.

$ o I o

A A ° not

/II1117

'11"I %AN5%

1111.1 71.1/41

518208-8srto BLUEIll DRIVER

's's 0704

..4 ono

ss'Ion

170..1 MUNI

1177 578208-8

DRIVER

"1 0705

5112510

+1241.5%1116 1/1/711 111

11V11

1/71 57E1208-8511 GREEN"I

DRIVER5%

0706

uo

BLUE

DRIVE

0121

-maTvo

220

RED

DRIVE

1171

-C/01T

5114 lrj

1171

GREEN

DRIVE

1771

578182-12BLUE BIAS

Oro

578 82-12RED BIAS

07081110

RED

BIAS

1111

110

578 82-12GREEN BIAS

0709

.01

COO

1171720

SSVee

1/75 1121

1101/411

M MY

onssow

1424.611

042

Ivm I0

-1410.041

7.417/15P-S/14,53A1VA.11T101041101/

Cr 11111

"II/ 41

, How oscR5u1sE815sR9R-P1E2R

IlL14-1.17;1

570194-11

ow:- 11C10 7 08010806

OSC578c1311;k11

u"

:112"

OK01

'FL:1711.1'1/41

'

03°°

+ H 02grii 1.::' r

NO /JO1113 1114-13 e

1.1 r 1,,,,

1,,.. ,1,11,11.n.;z,.

5.6

IlII1P1571-ClI101170 WI

110.141 .4 /I 578194-11

`" "V11

PRE -DRIVER otto

0102

11003

or :011.11,,,I411

01;r1.

M700, M800 RGB a H. OSC.

INS

01"--

IOW

578194-11'It PULSE SHAPER ligC1/11

POO14,I110

-114vv.

578193-11 PI 1

DRIVER21

OMB

11215 II

116/1(11111 I 11 4151.

1-1111/ 10113 10117 CITILS1

ON

COPYRIGHT 1975 BY ELECTRONIC TECHNICIAN/DEALER 1 EAST FIRST STREET, DULUTH, MINNESOTA 55802

SYMBOL DESCRIPTION ADMIRAL PART NO.

JT

502

11

0021f

on001 NW MI

CON

!NV NOV

I'I oix, I mie

.41.1,t,5113198-11

"00102.

OUTPUT

0103

00 .4/2004

11/02 MC

1rw",4 (4

C2 AKE

f1 a

7.7' C2 11/45i000

11101

*a,

5NMeeet-femm

11111

MOW

IISI 440.M

111 MIR A/ 11CIII

/104

1110?

UMW eff in ,AU. NM

e C4b000 0,01ifflossoes

0 1510521

00113

ID00103

Tols, 31sOWN&MIMI MT MIMEMeV OMNI,

,_!._.'"oP.

011

12 11 .10

NI nT

1111' :71041 1/415 NI

0005 11

J100 11001 1.54

C

C

C

C

C

rl

014

1E5

soms011 Nut 1110 1101

O.

F900 - fuse, 1.5 amp 84A4-7fuse clip 2 used 84A33-1

F1000 - fuse 1.5 amp 84A4-7L900 - line choke 73A31-23R153A,B - 250K, dual tint control 75A195-21R154A,B - 5K, dual color control 75A195-20R155A,B - 10K, dual brite control 75A195-17R156A,B - 5K, dual contrast control 75A195-20R630 - 200K, vert size 75A101-28R631 - 60K, vert hold 75A191-2R634 - thermistor 61A41-9R741 - 20K, brite limit 75A101-47R901 - 22K, B+ 120V, adj 75A199-31800 - coil osc adj 94A351-3

PICTURE TUBE

600

Ia. 411(0 NN OW0HO, Or yetnen 5 Ma

/10

(014110* NCI

5111111 COON NEI FM NO 0511.

1105 sea 0.40(0"01CRT OCUS

JO

no 00 014100

0.

00111. 4-00011Iry-13010

51

NM NI01011I

1.5111

115020411

105

110.11C11-5

NV

021

m ' 921

":;'v"AvirS(COT2I" :00.40:S.1"1'33;itzilv

M V 19VE J T CO2 1:10019V 19 VEJ TCO 2 ::,010c7,

RUN CHANGES0 SW, of IMIO proctuchon.

O51n40l spno/ Board changedfrom 48950-? to -3. 5I011Of -IMO prmfac 6pn

172\ 01700 M800 808 8 H OSC Booedctionswel from 48951-5M-5 04900Ftwer

Supply Board Mongol from48955-2 40 45

1110008m Custnon Board changedL5.-2P*0,48951-2 M-3 Connectors11000 8 8/000.1,4 001,1100SWIM 4011010 oroductron.

,;) M700, M800 800,0 cnongeo fro,. 48951.5 ro -6O/4600 Vol 80.4 changed fraon48952-2 to -4

0 8116 ,,,68127.96,9.

tre1/e4 re mOst MAW M100.11/5COnfr 1010(1 OM IWONina WINO NV AWN .114444fef 011141-0, 01149111444410

WSJ WIXOM ZefIff: XVII,X1 Wit s Aft.40101, 01 wart Of ft X .o(/1 r!

WWI WI 1,41/41111r1 NOC100' Natl.( Of 11 xi+ XPC4(17 0.11.0.1 ONO in /MOW .41S me MAWX r40 401 II( WUX S Fla M . //4((e e

01I 101,le

/0/15

0111.4TO

"elifCIXT "".1%1%L111:1': s.4I1:.,10I4 ;..4aal 0

1MU

01001 NI 118 000 0,401oe/ 'WO hgl Ay, 1-1401

1 Pt/XIir, 5.1,4

fie

0000

101

5%

01012

50. 1144"1/01 (NW10 ow, XiMa 14 114019411.1. AS 004SW11(001 019M44(III eief.td etemePe NI fen 00 111 04045151005l, NV/9P [MX XXXINOXIMATIS N ON Or MI asON WO 10 MIPS 0000044940444 IN ANN MU II AVON 104 OK "Oa OWN19 f11004 fl Mors, 4(100143 LON WWI, aroxxor

01 /141/44(1 M te MOM 11 II eff OA, faalle CalIf MYOSIN ilea N Nr af a ANION a/01W HlArS41.. 1100014111. et! site m f too ee reef?f;;Nna ~NI 0144(4/!3 tweed" tapn110011 env,K71001.1 fof 4.411. 4t OW a 01 0001510

E\SIMItt N 0/040120 00011 My roof systerneCMHMSO Walla Waal 10.04041010.14105

C0011100 10/011.411100111101.0104 al ClaPa /14041 /144

41011

I -S PIN4 I

CI 0110

1004 11005310 HO

is2i ist

MI000 PIN CUSHION

SAFETY NOTICETHE ENSIGN Of THIS RECEIVER CONTAMS MANY

CMCKTS AIM COMPONENTS INCLUOE0 SPECIF1

CALLY PON SAFETY PURPOSES. 105 CONTINUO

PROTECTION, NO MANUS WOULD BE MAX TO

THE ORIGINAL KSMN. REPLACEMENT PARTS

MUST K MIME TO NOSE USED N THE OM-MAL CIRCUM umnct NOM K PEMORMUI BYQUALIFIED KRSONNEL ONLY.

0 en 0r- a CM

GO051

D. es3C 3E0 0 0r- .0 rz

In+ co

o

0.51 -

--rno a-

4=54

CS

CM

crs- rnO

O

Crs

CO

C..O

(.4.4

D

CO1- -4r-1rn

1,1O c.30ran

Scr-044r44O

r -t° - C:s 00Col

-cnlas

Oo

N413

-vs

O

14

Oa

-0

rn vs -.rn =00ac r- -rn

rng=

0RI

..--.. C-1 .3-I4, CO 010 070C/1 0 0

3S

.4C =corrt

3Crn

CO

='CO

..151

O

CHASSIS LAYOUT

OOcici

IEI

0cici

ci

ci

CI13CIO

0 0Q.', co

0-0

n.4444

O3030

r+1

310.

if 14

O

0

0

Ma=2 -n104.0c--

0 3ON0

1,' X> 0Z..ts°

81(11O00

-O....

000000000000

0

ADMIRALColor TV Chassis 4M10

0 0 0000000

@0

oC)r -

O

.4=0 X.

o-.3

441

0r-444.4

00

0O0 s-41.3

se 0G. 20

C)N51

O0

Co 0-4144. 2 .0%SSO0 0 c5.

ces

O

OCo

,=, =-41 C'x'00

ao -74

.10

COPYRIGHT 1975 BY ELECTRONIC TECHNICIAN/DEALER 1 EAST FIRST STREET. DULUTH, MINNESOTA 55802

1595WARNING

MAGNAVOXColor TVChassis T995

120 VAC60 HZ

JULY 1975

J2

TO GROUND.

TO TUNER24V INPUT "I

TO TUNER ACC

.120

I1 7

2

3KEY

ELEcT,...0472197 r-1,=7.4^13irCOMPLETE MANUFACTURERS' CIRCUIT DIAGRAMSAND TECHNICAL INFORMATION FOR 5 NEW SETS

P2

TPI AFT

6.2V1

7P2 AFT

6.2171 2

MI01AFT MODULE

49 L2 703637AF TCROSSOVER

MC1013006

C2010004T SOURCE4 V

6

AFT1.4IV

M104IF MODULE703636

7

T7N71°PIN

P2

P/JI 3

TP6.64V

7 I SOUND

4 SOURCE TP204,_wVIDEO T p 17CD,

2

KEY Tp% 13.32V IF I.18V10 AGC 3

.----. WI ri ICBI

2.1 AMP

0

CI.047

4 150VAC

7 Y

C?4700

ISO VAC

P20

SWITOR01UCIOT

LOCATEDON REAR

OFVOLUMECONTROL

(R4)

K/

T2

f;RN

0-1.3 VAC+

INPUT31V

9TO .24V

9.9VT 4,

5

TP18

PULSE SOURCETo .1000

13SV SOURCE

MI03AG C/SYNC MODULE

703638RF AGC DET

DELAY

LCL,TO .100V

C1911.L4

P20

O

R2

RIIMEGin, INTERCONNECT BOARD ASSEMBLY 703649-1

1000MFD MC

C26 =/21:771 P20

35V 1V,i7 6

3

PILOTT°LAMPS

5 38,_1( YEL KEY KEY

RED 471:1/8

IV

9 13

TO 124VSOURCE

SYNC CI

MI02SOUND MODULE

703639

4.0UAD IINPUTL2 LI

id:

RI*MA

TP3I

1000MFD35V T O28VV

SOURCE

TO AFT SWITCH

TO AFT SWITCH

.TO VOLUME (641TP5 2 TO VOLUME IRO)

6.6V19 or P/01

=TO PIN 4I

B TONE (R3)

4-0 TO GROUNDTP4 .----

AUDIO,r1

5 ?

TP7

16 01ASPEAKER

P/J I

TOCONTRAST

IRS)

TOVIDEOMATIC

SW BD(PIN S)

12 s, II

6TV

VIDEO 08.5V

3

CHROMA

ee-f3:77V

Tpeei2

5 II 13 6.311)(;)9.05V Tw9

CHRO6MvA0ETOP21 v,v1MIO5VIDEOMATIC MODULE 16 24V

703641 10703656 121

B

II

11

19

115

PULSE SOURCE

9

4V

M108LOW LEVEL VIDEO MODULE

703640

)6TO 24V TO 4100VSOURCE PULSE SOURCE

3®7 246V

1.22V

VIDEO5 1

12 IITP30

4-4123.3V

0

PART OF

I CONTROL ASSYI SECONDARY703652

(NOT USEDL - ON SOME SETS)

TONE'rRI5000 1,-,

RED/ILKILK

SRN

2

16.2tAC

C21000

DI

M02

ORN /22-11%4C

wNT 6M1C1

CED23

IM6% 28.8 MC

BLU660V

RP V/12

W 10 C31000

C41000

CI

I .22100V

SI

LORI DEFEAT 1

-

L _ _SW__ .1

rr

tez 5AC1 W13

RED7ORN

GRN

WI5

V/I7 !LL_

D3

D4

CS1000

R4

°7,7 tvAc 6.3 VACTI

C6

10%500V

120KI/2W

513

-rW26

M114POWERSUPPLYMODULE703648

R724VADJ

R3HV00.1

W25

W22 7

V/23 3

W2 5

WI9 2

W2

W21

W27 KEY

P/.1 23 J9-

-.= 206/LOR

100K

PI23

P22

13

KEY

4

TO SOUNDMCOULEPP/ 9

KEY

7

P4

SYNC

TPI 9

HORIZ AFC

TP4I C4

231003

10%,Co105

CI6 301(R2

- 150 'law10% 10% 5%4

MI06IUPU2Ltr

SOURCE =C17

v253:031,

HORIZONTAL MODULE

)2TTM3:6845 -.6V

TP29 DRIVE:0-;12

0 1/2WC14 RETRACE/SCREEN MODULE1000,10%

8

703647

)ft LI ',14STDZ R41811

M109

TsOoo6264'E24

A

*OUJIPLIT

100 HORIZ OV

67 A T4330 0

T p1324s1REIAATp _434

icLR IRBup4 Ett_4RIC

194N1

Magnavox Consumer Electronics Company is committed tomarketing safe products which meet or exceed applicablesafety standards of industry, government agencies and in-dependent laboratories. It therefore uses parts in its productsdesigned for maximum safety, reliability and performance.

For continued safety of this product, parts shown in theshaded areas of this schematic must be replaced with onlythose identified in the Parts List of this manual. Use ofsubstitute replacement parts which do not have the same'safety characteristics as specified, may create shock, fire or;other hazards.

For maximum reliability and performance, an other partsmust be replaced by those having identical specifications.

Under no circumstances may the original design be modified.or altered without permission from The Magnavox Company,otherwise the consumer may be exposed to fire and/or shockhazards.

TOVIDEOMATIC

SW(PIN

TOVIDEOMAT1T

BD SW13) (PIN

TOVIDEOMATIC

BD SW161 ( PIN

KEY

TOVIDEOMATIC TO

BD TO SW 8D COLOR2) GROUND (PIN 191 (R7)

II7

3.IV 1108.34V

TsocatilVIDEO C 2

05,100V

9.05Vpcj12 It

.Z8v HORIZ. BLANKING 17

13.77V CHROMA

2Loitil.VERT.

BLANKING

0 3

5

TO 24VASOURCE 14 #5

5.5V TN° CHROMA13 13

BURST?IS

ETpI

16 4 11 6.6V-

I

R2I41K

14.4ViR2?

le47KTO. 4VSOURCEMI10

CHROMA OSC MODULE703643

12 GATE 5 MIIIPROCESSOR MOD703642

2 ACC 19 CHROMA 2 14.2V

7 RII:IL

1

AC/?TIM 22.

613COLOR 3 I4.2V

F

12.360.V

13

TPIS

TPI3A C1 IS 110187 14

1

SOURCE

2V 6 II.6V10074/19

6.9V A t°°°11 6083.58 MHZ CW

142TP14 3 fir MHZ CWCHROMA

DC FROM FLYBACK

O60612.B

TP26

7 .6V II 6EOURCESOURC4PULSE

TO 24V 250V

VERT BLANKINGTO

SYNCa TP27

12

6) JOE.PINCUSHION

SOURCEce Ep., 52

4)-443 1:TC/0 M F D ,3 5V OV

7 .28V SOURCE)----°135)/ SOURCE

c---i125V SOURCE

KEY

10021121130e2Av

P3

21V

4V

M 07 R29

VERTICAL MODULEpLEV70364663 R23 626

HHOOLD *ELT :Mt'4

II8 l9

6 VERTICALCENTER

(1 PIN JUMPER)

35V

1615

1000I/2W

C61000 MFD

22V

D4C5

.4.450MFD150V

TO 135VSOURCE

VERTICALOUTPUTTP33

29VTP2S

VERT. B 1

C3 R14 L I

0.100o :330 I

MFD 1/291'

36V

R6*12

5W

D6

01D5

6

41:TP31

4"--: CB241V 10MFD

650 300V1500

SW

2.1 31,4,T.51 p24

P7

3

RIB

. OSS5%

100VHORIZ 0PULSE

SOURCE (f)

2

12

135V

TO I35V,9 SOURCE

1000V 0 TP36HORIZ OUTPUT 4IrTP35

TP37

9

6

TO 125VSOURCE

TP42

C 950 MFD

150V

CDMOO

IV*Sw D2

C12

claIWO -230Vism NPULSEona@10%

SOURCE

7

6

4

)2

P8 V r HORIZ 1 4 3

"r j8 a.?! 1 L DEFL1 ,-J 8 1

DEFLECTION YOKE

COPYRIGHT 1975 BY ELECTRONIC TECHNICIAN/DEALER 1 EAST FIRST STREET. DULUTH, MINNESOTA 55802

793e

TP40

TO -250VPULSE SOURCE

1TP39

31

KEY

J7A

.178 1

I 3-4

6

3

J7A

L

*J9

HORIZ. SAWTOOTH

MISHORIZ SCAN/HV MODULE

703653

pv 01 HV

RECT/TRIPLER

300MEG

R2I8MEG

1R6ffl1.4V/

225MEGO 6W

6KV

P25R4

4514E6.8W

J

CONVERGENCEYOKE

1 HORIZONTAL

11

WI

RED

W2

a.TO CRTFILAMENTS

VERT. SAWTOOTH

BLK

W3BLU

MI12CORY

MODULE703650

8

I 3 RED

3 GRN72

5

-------7=-7-

14BLU I

1VERTICAL

1

1 1.6V P/P H 2 4.5V P/P

EPART CF SECONDARY CONTROLI ASSEMBLY 703652

52REMOTESWITCH

R191506 1

620113K

J4

V 3 100V P/P H

4001111NMIMMNIMI

9 1.3V P/P

17 100V P/P

P/J10

4 3

R26IOOK

TR2 3

G Y

03 ETP22

V

TP2I--R25334

.5%

TP24

R2133K5%

R2333K

+5%

5

a

9

6(

TO P/JI- 32

TO *I35VSOURCE de" -

P6

J6

J25

WIO

>3WII

2RE,

TO CRTFIL*MENTSOLRCE

I 4 6 A3 2

4KEY

6 3 "1 "4KEY

5

We V/7 W9 We

M129V

113

FtGB/CRT MODULE

129V 703644

67 R9 RI 1

W5WI

-4.7 ,DE DRIVE DzvuE

T pi6

J24

2TP2 4

P3

W.?TP4

mpeormilimmmerim144414440.

4 23V P/P

41%.1M111111191.1g1p1IIIIIMIVI

amarommia ~MA

H 10 1.5V P/P

H 18 20V P/P

22 7V P/P

H

V

V

11Trfb24 13V P/P

250VRED SCREEN 794V

GRN SCREEN 602V FOCUS

BLU SCREEN 666V DISCONNECTJ2514IJ

H

11

AI "14 d

2

4

6

II

F-3 7

12

4115 14-1.1 *9

34 80V P/P V

CRT

35 21V P/P 36 5V P/P V

H

5V P/P

5 3V P/P

V

IM mMIIIMII06111

19 lOy P/P V

H11111.1111=',..:

21 10V P/P V

25 875V P/P H

28 875V P/P H

30 240V P/P H

32 7V P/P

37 9V P/P

V 6 7V P/P

Wwwwwwwl

164441\111

12 .2V P/P

20 7V P/P

23 12V P/P

H

V

H

27 130V P/P H

111./. 110.

29 100V P/P

V 7 .4V P/P

13 1.2V P/P

r

H;$1H 1.g 1 .a

31 240V P/P H

V 33 45V P/P

V 4V P/P

H

V

H 8 .2V P/P H

H 14 2V P/P H 15 5.5V P/P

co i

-

T995 Signal Flow Block Diagram

alrl, .1

__A<

I

IgE621"'t'

..L___

r

L

MAGNAVOXColor TVChassis T995

!Palmas...re

H 16 1.6V P/P H

xSi 21,4

.rnr

rn

0 nra1A

r

r%

2

IC<

ir 2

100-

r

1.1S100IA -

14',I;

S

L- -J

A:

cf-al

00LacusZ.Lao

zi0:8.ml

-.t.1

.., r 1

:

g 2

41_<2 .+-4.i

1.

,AA *,7, . 1 FP-Om i

sie.

, i.'31 !. I

-Sirr

-I.

o -

IA j,61,1

,71

?0:

_J

IRI$

z

J

V 38 L


1596PANASONICColor TV ModelCT -324

JULY 1975

CR

C'J 6

0

L11

A -A

ELECTRONIC 7 /-1,7z7-Li_qjdna xic

COMPLETE MANUFACTURERS' CIRCUIT DIAGRAMSAND TECHNICAL INFORMATION FOR 5 NEW SETS

UHF TUNER TNK36100EA

TR,KR 25C 2 1 5

28C611425[2116

VHF TUNER TNT0624KFE

- zl 110 IF CM-0 0-

13

'1 5-L13 GM

4161.Mr 1at

2r-1211

11U

Z4

411 ;31

11

Alf 414 G31

TR.2SC1111111

WA

/'Sn

311

ti IR

tit

0^1011

311

TNP65316IA

[v...xol

-

30E

104

1507503CONVERGENCE 1104RD 31 'CIAND 5'014E

SSE16111.

2802211 23471911/511096 204.414

ESC 1 SRO 2205114A

2101311

26360 11210 254245261144

0103. T104. TIOS. 1104 T151.1201.0202.

0903, T404.1902. T903 3106.

NOTICE1 RESISTORA1I 44. 1 *IV. 515

55.4 MaI.A1 CNN 11 R-1000 111.1 0.090

A Sol 4".0

2 CAPACITOR

444., .. 141, caAsIala121.4.114

O,01,4.1 41.41411 10.TEST pOIRIT

TOMATO :ZArlZIAT1TT... 10"..114 b, a .air /4. OC ZOn CON V

cs spai all .4144 ars .1 Ina

I I .11.44 ...cases Kr*. maw Km...awn. 4 No. 10,1. Ow 1 an .4.

*ben .14404 41.2 at owe .640. mix'. IN, 1.1110c. 1. Man .11. Iwo

2 414 R.. e. 41.1 1 I41

TNP65 1 I 1AZ

3

IS

;281119 OWE f -PG

0,2EGN, 4% 0.1T

VERT.So CR,/,,UR

n 68iI14, .0NAM

1014.

q1l 64.

,Aje u11 a13e .l

MI5 $1

ID

16101

",VOLUME;6

- -°Lon '1IN 0922

:14±_<[:/.4.40

..... ts, %I:1r'4

DEFLECTOR YOKEH. *-.;

, 511

.9

fz

ror

1310

;,40 6

IIIpx33

NI

1-F,84 -L11,__, 30 r a) .t.C1eI54 41NRrf Wfr; ai eirc'a ami

47.

4, t., .

OUT 5.41114 3t

2SC 446

0 0 'I 4.4.

0voi

T.tAFT 42.5.,

RE51

012 4660.01 cr.IF

4

AN 1 77's;:'*-

435. C6'3 -

-6--:

Dr,T.: 31 C t 1 =

III-

t:x?4.' 9. II, 11,

' ,;: SOUNDY

TR n525C561 25C562

11, VIDEO .6 202 VCEO 10

wig

131

65131

AAAAA SPL1T441,

C.IG304

TRW.21461144

13tr re0-

rt,r -

.41.le [AA topI,

fad4-4140.N1351

.

t r7-±3I0

4.1

Itelmot 00171o '05

331

I5111/80 sPULSE AMP

I5040L01

26

1.) ,.z 1 -

TR50325C 6620

ROASTOSC

ZAN

ova iek

e '7316 NFI 3.901

IL,

e

1170333

11

.504

'r41.K-3 L4.70:45.5C

T1I153256 1

0446 0

DRIVE

-1-5

-`,_..'_CSIIIIFIT

TR 032SC563A

3)2 V1020

In

IIR3.6

11.56

a zi 4, 00.0.09.0 0911 TI 3 3

-.1500"'4yr. ,-041

I r131 rT.LS

0.1 413311

cn

Nc

A ;:al I

n .

1 EV

V.

0 ma

0SCREEN

TNP65924AC

Et' -n

tra

Zia

co sr[ t

.41)15.

2

131351

IM 1

C60 64289COLOR PROCESS

UI

00'

'

XI

1010nt:

"MUGG 1111:1110564-05 RKILLER

06113:544.!

*we co 33 ea

45/0)

3.11

Pop,sx.141

Fi

0.4.':--"3"sr,. ilt :;:'--

- SO 46 44

zr031141:7 ,,

[ .....02

1001

/.

5

Mc.ou7

'7 .4 .31.T.3.3 71r -r erl

0 1114

kizz

'tut

Cll

250°662.0 .

mmuf401ACC

153

3031151

131

7.It

S

431.330.

4

3134 (AI

-

:L:'

.C602 05343CMROMA OEMODuLTOR

1112/3

NI

F.RUIN

unp.

Taw.2527)005VIDEO AMP

ROI

18

31I1 D55:

013.3

n

[scohocc SW]

;

31631

3441.

0000

0-5

--101

0.

13

-as eak

IRO

77-0 OUT

11,

;:e.2112If OUT

111)

LI40 5.1

"411

15343Lty asc woo

OUT1111

'053 I1351

65

IC4fAIZI

10.1103

Itle916

6061

8Rr2EG111

4. :110c

71145.SIC .446..0AUCOKI OUT

111

LOU

165

11, M 11415-4. ...VIM:312

.011 11 ,--°3110.

.,. , ::: 66 OW

S P

4,011,111.._423.1111

1/11CION

;1%00 4Ott m

°1831 1.1161

0 [Po* cm

'1111TIALLCA

120VAC

V

as.r -5.43

-1.330

rn,1546101

Wipt:k

L


UHF TUNER PARTS

C 130VB 7.6VE 7.2V

iht

6Vp p

'/1/1 6Vp-p

1.6Vp-p

3

34

C 130VB 7.3VE 7.1V

OV 7 32V2 130V 11 125V

m

18

L354

R364

L 353

TTTR351

- R362 -L 351

R35IL 352

3 32V 12 190V4 570V 13 520V5 600V 14 6.3V (AC)

[6 30V

4b0)

AV, I

TR352

-

C

2423

22

R361

eC353

R353R35

25

1-160Vj

356cB.DR1VE

- R354-

C35i

R360Y10,ThC R355

-R363-

INJ

%lb

R on VC

- C352

I R.S. CR EEN

G.SCREEN I

cn

ge1C

Et.SC EE

I cr-_ R3 70-

1.4

-4

26

27

C 125VB 7.1VE 7.0V

+160V

-R369 -+160V

28

SYMBOL DESCRIPTION

R118 - sound reject 500 ohm B EVLR6BAOOB52R182 - delayed AGC 5K B EVTVOUOOMB53R903 - AFT adj. 50K 8 EVLR6BAOOB54R820 - fuse resist 68 ohm + 5% ER012HJ680R450 - sub Vertical -hold 50K B EVTS3BAO0B54R465 - height 200K B EVIJOUS15825R468 - sub Vertical-lin 2K B EVTS3BAOOB23R469 - Vertical - lin, 200K B EVTJOUS151325R479 - Vertical -balance 1K B EVTS313A001313R614 - ACC 10K B EV753811001314

PANASONIC PART NO. R817 - B+ adj. 1K B EVTS3BAOOB13R610 - kill 10 K B EVTJOUS15B14L502 - choke coil TLP408T505 - flyback )(former TLF6404SFt - fuseR220 - sound control 50K LR259 sound control 50K L EVA85A06A54LR380 - bana-brite 100K B EVX59AF25550R381 - 2ohm CR386 - sub contrast control EVV58AF25C53

5K CR387 - sharpness control 5K C EVV85AF25C53

TSF35503PANASONICColor TV ModelCT -324

Ref. No. i Part No. Description Ref. No. Part No. Description

UHF TUNER (TNK36108EA) PARTS 0 D M01-0007-00 Indicator Shaft DM -01A

A Indicator Ass'y DM -01B 16 DM01-0015-00 Pinion Gear DM -01B

t DM01-0051-00 Supporter DM -01A lit DM01-0006-00 Indicator Gear DM -01A

0 DM01-0074-00 Indicator Drum DM -01D @ DM05-0002-00 Shaft Assembly DM -01B

® DM01-0073-00 Indicator Drum DM -01C 14 N8-827-07 Stopper 07

® DM01-0044-00 Indicator Spring DM -01A '20 DM01-0017-00 Stopper DM -01B

DM05-0005-00 Indicator Bracket Assembly CM -016 21 DM01-0018-00 Stopper DM -01C

6 DM01-0046-00 Geneva Stop DM -01A 21 DM05-0013-00 Double Gear Assembly

7 DM01-0070-00 Idle Gear DM -01C 21 N15-812-11 Screws

8 DM01-0071-00 Hub Gear DM -01C 21 N9-814-02 Double Gear Spring 02

:9.7 N15-812-11 Screw 24 DM01-0002-00 Housing DM -01B

10 DM01-0071-00 Hub Gear DM -02C 24 UY01-0047-00 Inner Cover UY-01A

L N17-818-04 E -Ring 8 UY01-0026-00 Cover UY-01A

g DM01-0069-00 Idle Gear DM -02B # UY01-0027-00 Cover Spring UY-01A

13 DM01-0045-00 Indicator Spring DM -018 t0 N7-811-03 Ball 03

B Complete Tunern (3.0 DM01-0062-00 Detent Spring DM -03A

14 DM01-0001-00 Housing DM -01A t DM01-0063-00 Spring Retainer DM -01A

CONVERGENCE ALIGNMENT

Convergence board of CT -324 is different from that of CT -914. Proceed with the steps as shown

R

TILT-RG

RG-DIFF

RG-AMP. LEFT

RG-AMP

R. StaticMagnet

B. LateralMagnet B. Static

Magnet

B -AMP

G. StaticMagnet

TILT -B

B -AMP. LEFT

B -AMP. RIGHT

RG-AMP. RIGHT


1597TRAV-LERTV ChassisTR2- 1 A/2A

ELECTRONIC E77=Fiza 36TECHNICIAN/DEAIER

JULY 1975COMPLETE MANUFACTURERS' CIRCUIT DIAGRAMSAND TECHNICAL INFORMATION FOR 5 NEW SETS

MODEL CHART

MODEL COLOR TUNER CHASSIS

T9P800T9P802T9P803T9P805T9P827

BlackWhite/RedWhite/GoldWhite/AvocadoBlack/Walnut

94A363-6 VHF94A361-3 UHF

TR2-1A

T9P800MT9P802MT9P803MT9P805MT9P827M

BlackWhite/RedWhite/GoldWhite/AvocadoBlack/Walnut

94A281-15 VHF94A296-4 UHF

TR2-2A

1 Lae..

r-

imot"C1

1.101 (.717rev

2.E"

1.1034

VHF TUNER 94A281 -150n2 -u-1

1 L iota LI 450 Or 11 UR°1 0011111 050101

11192

111111 012 130. ON CP

;PIGI' Sr 3111

100o IIIIII loPu,

- 1

cm,1.410

011,01s 7.

61

1.113I 1E

con

0107 III?III

CI,,1000

L

3GK5y175 00/101

v101

III I UHF TUNERI I 0-41-1 r -1.707 r

001401I 16411/4140

II

//1310101

...Milt CI

T. PI!211 III

-0110

nl 1401411(11119 1041)

40

1/2 5LJ8(01 01111

0702A

los4 11111/

125

I II 1400C111

3

400

VII I UlfTog Is9111 3,10040

90213 15

01 05C07020

0 Cl"_ Cu"_

'I /CI 01 IIIS

to! IC4/ 101.21

94A296 -411102-2AC1514 I/,,,,1------- .i

CO III (0%

1352101

1,33

01521050

93A59-1of

crass.1MS

emire.1111MEM57B21-2031

015.

.falluncivaItsallil CNNOf ofOrrI544 rfIrififl NM Init.

rratorl Pei roll 1111 sr Orin 0 OHIO& I40405 '/5171/(00.',off

174**,0I411 10%.1911$2 Ormfirst "wary0C 1.0:4C11120.91(1)41Im Mt at Writ'1,0. mu /10/0440 OPP& DC 4117475MHO 114.9100 101 .64-01 a DIDIVII .17041sme64m. etyma 101 /I 'az Itootrxmwsominoglar ost tsoranot rossawafto sitsgiro" IIIINCIlaf AIC14491,197.

rtOr it001, (410,

000411

II

SIM 414 110 5011,170/ Jiff COM POIII/If/50411(1 COMIC'S ID401 SW Of ilOyle

M501 0150

rC5C15044

Of or

1113 10

100

il/11133

1

Ity

V031

0114 Mt 144211-105LJS36-I0102

r0119101

19111069P4

0304

4016A0204

IIJVIIv202

00 0017JZO0401

60115AV302

0 00 00FIFO?

O

192

;01111

021

11:00

411Z6

4r0 00 00 000,

TOP VIEW OF TUNER

L122

T . P . 1

1/28JV8

SOUVIOI IF33:8mvaa oat,00

rireq,72,,;;

1:7.122120%

P W S 7140463-2

Or14,

0701

:24 ilLoz72,7,T,

I

..1013*31

0,0101 INS /5 d I hi -CONVECIf0 OMJS/S-USE 60111/0 11.10f0011 Salle NCf-IVHF TUNER 411W11101# DOTS ON TUBE OUTLINES

"415 55/0 V101919,5*V102 d3.C7.0N INDEXING POSITIONS-

MO/CATE KEYWAY OR

5LJ8 5CS1 VHF OSC 10ASP4*V303 I MISER PICTURE

VIDEO MP

4 SOUND IF AMPA54

V

viOt 6 3.HF3GK5

3AM P

F "r8008 3HOS RE AMP

ACCESOUNO-OUT T

JV8

ON -OFF

SNITCH(20V AC

60 Hz

4DT6AV202 4

V201SOUND

3

5

GH8A

V3022ND IFS

SYNC SEP

4.1.9 V3011ST IF

.2 11JZ8

vaoivER, OSC

EFT

OUTPUT

CR502

USE .11411-12AMP5125i2501

0501

MY

17+ moo sot of mo 1011.40

4DT6A30010 Of

V207Ir

105r

11054101

1242200

ALT PICTURE TUBE

9AEP4"CR404

95115-9HowPHASE DET.

8F01

0402RII OSC

5

TUBE LOCATION CHART

70Ir /00514/

ErinT :5

"Hl 4.22

5601010

33GYTA

V403NORII 0,11Pul

6 DAMPER

L.302E 11110 .

Cool0.20%

L 5011

75,40/116!_j

1302 1341111 441

4BZ6ISV301

1/26GH8A,M124,, FOIL'

T30,441 ot Orti

1)01

2121

IV

I WYIm

309-1-0.1.112

014IH

1207%

L

3031412101i

KEY OFT C3.3115901010 III

34

riti Eri!9365-111/28JV8Noto4

111.6,00Ty

- 0300 7

20%

5307

_JP:143.341un

j L304

II Blot 452%

1111

271TO%

1027 1313All

5% ISle_

VP,

034

2

-SY

1

ART

.0

414511

50 3 R.2

18C2

V404V RECTIFIER

0311OIN

L309

REMOVE

SLEEVE& TUBE SLEEVE

SOCKET

0REMOVE

SCREWS FROM

FEET ON

METAL

SHIELD

DISCHARGE

2ND ANODE

LEAD

w -*C4:TNU.NBEEEMCGT°0RAVPE

HV ENCLOSURE

T201 NM 111W wzo,r- 1 or iv Jaw) vim!'12o

4, 12114110%

21(.11111031L JAM

14202

7 lilt Iffigilf MPH(WY 1/1051III 11II ITMelia

_LWS," WO

JAW 110'51171 ---,Of 11C4if Pull -

l'.;..". 18171

-r -----------,,,I UP'

2i11II

1120

41114

000ALC

I"C

0 Or

1.01 1105.444, 4.140 2 ?NI;

OP,

1/26GH8A1/28JV8 SYNC SEP.2(213 v3028

ACC 5410721

7711..

Iva

.141/ 116

:PP140

.71t(

554

D

40117

1431220

1/2 17JZ 81410 1 001

ir

K1- MP

2401

0401

120,.2%

.02111.4%

1141

114115601

.

i.4.45644NEC

HEIGHT5014

PERI43E11

4214204

0111

0110EriNN 1475

4700 4/1 442/

'0% 11, 390

E

144

1.9741ur

WIT03911

WajliC2#101, 209, 41 2411

W%* 1/2171Z841111. /NMI

04018

_ VCRT.

5001 141170

002

VERT. isc2WI HOLD11.3071,10

702500 3404

40

uo

t'..171

"1 501

14311541

9355-92- - - -

.,oc POSE 21!CR 471

10145 Tif-4-

93C52.101111114 1111.1111

4

INT laftMI6 R.ftm I* 104 06501DAY RfIlaCfOlIft.101.1,41(ti001 /00710. 003kV': 5 5 At 460 f PHI 150,

Lief C511NV 241N. Vi IMOIFIO#0 161111 5n 74 04711501 low

9501(Th 51

01 0001101 "1502

filier V 11,12 10011/1-1 SU OM0

MI 1' - -

'111155011111:,1,9

'

0 N c,,,5,-,.. ,..:,. ,

6161043310

/ASP-044 o, IIN

410315031 NIP

",(1,1

4 1,1./9 7

1444

011

2-*C5014 T C5041 CHU

15001 70011100 1504 SOr

alp

lf,E 5433

OLLIE' IMI

Cool

ION1

rrI0010+to noWS

4- 5vAce,t

1/233GY7Amu/ 021402

04030x 001114110!if vita(

-0 trrI

4,09

g IOW It

0035

+1121141.0

145:

3403r

13221.51

72E

L310!NT

111

71141 %so

uol.42:Zirj1321.101

sir -4111 710II

009 OM5410.7-±

WOW

I30EC 1 2140pato NOV

VIDEOCONTROL

JMN

0E101801M 43

111 10"

AC

rrAWN/ 1402

9L404

43041010

-rj_244

100,110

143311e%

110.1gT

197 140,01494111411X I07.04.9417 X POIIar

L40311

V233GY7010(1

,Ny v403112103

-1411

I1111

5

1E0

Olt

AE14«10ASP4,11111910

TUNE

' V304

pilact (41,10e 4115(5.41'WW1 A"4IIINPI 70 015101 097000MISS Sr 91/ ("MOW

RUN CHANGES510114, production.Re1,110, R501 WS CVIVINI frOff, S. SI2 444.44,

ruse F3011 2orno.tmps MOH .

33GYTAv403 V402

#1011/9 Of POLARWO Vito ,-,94frS

COPYRIGHT 1975 BY ELECTRONIC TECHNICIAN/DEALER I EAST FIRST STREET, DULUTH, MINNESOTA 55502

no stringsattached

NEW Weller®CORDLESS SOLDERING IRONGOES ANYWHERE

A professional quality tool, Weller's feather -light andfingertip -handy WC -100 Cordless Soldering Iron allowsyou to make connections anywhere...withoutdependence on an AC cord and outlet.

The heart of the WC -100 is its high-energy,long -life, nickel -cadmium battery which springsinto action at the touch of your finger, heatingthe tip to over 700°F in just 6 seconds.And no danger of accidental discharge.Weller's exclusive sliding safety switchbreaks the circuit when your finger isremoved, won't lock in "on" position, anddoes lock in "off" position for addedsafety while restoring energy with fast -

power recharger (UL listed).Loosen two slotted set screws and

you've got instant choice of four tips...regular, long -reach, fine -point, or miniature...each mounted on an extra -strongstainless tube to resist bending. Tip iscontinuously illuminated by the built-in lightwhich focuses on the work area, a specialadvantage under poor lighting conditions.

Try this for size! It's a full-scale photo of thecompact WC -100. And the real thing is waitingfor you at your dealer or distributor...right now.Need to know more? Request literature.

41COOPERINDUSTRIES

Weller -Xcelite Electronics DivisionThe Cooper GroupP. 0. BOX 728, APEX, NORTH CAROLINA 27502


The reader that canstayon, and on, andon.The 603.The price Jf the Model 603V -O -M is only $173.

The one V -O -M you can forget aboutforgetting to turn off. The incredibleModel FET V -O -M withexclusive Triplett Micro-PowerTMdraws only 10 uA, can stay onindefinitely without impairing per-formance. Ideal wherever frequenttest changes, interruptions, distrac-tions-or gremlins-keep your V -O -Mworking when you're not.

Truly outstanding features:1. Exclusive Triplett Micro -

Power (TMPTm) providesbattery life in excess of a yearfor carbon batteries with unitleft or continuously 24 -hoursa day.

2. Low -Power Ohms (LP,JT^^)-6range:, with 70 mV powersource for in -circuit measure-ments without damage tocornp-ments.

3. FET V -O -M with PatentedAuto -Polarity --convenientand time -saving, always readsup scale.

Accurately measures electric andelectronic circuits on productionlines, in quality testing, during main-tenance, in service shops and oncalls, in the laboratory or classroom,in the field.

One range selector switch operatesthe unit. One probe handles allfunctions-AC, DC, MA, Ohms-anda simplified scale utilizes only 4 arcsfor all 44 ranges. The Low PowerOhm circuii permits fast circuitmeasurements without biasing semi-conductor device junctions. The

DO 111 I hill.1011. 040

*ZERO

OAP

DEPRESS

300

Pc* 100

F 30

0 10 10

3

1.3

,0

G

BATT CHECK

AO

TOANSIT

Model 603 also has a unique,Patented Auto -Polarity circuit: pusha button, measure either plus or minusvoltages without switching leads.Make very fast voltage checks wherepolarity is known or doesn't matter.

See for yourself. Try the 603. Haveyour Triplett distributor or salesrepresentative give you a free

xl MEG

xlOK

x1K

x100

x10

xl

1000

100

10

AC DC MA

SOLID STATE

V -0-1A

demonstration of the tester that canstay on indefinitely without impairingits testing performance. You'll beglad you did. Triplett Corporation,Bluffton, Ohio 45817.

111111.TRIPLETTALL YOU'LL EVER NEED IN V -O -M's.

Triplett. The easy readers....tor more details circle 127 on Reader Service Card

Date post:	06-Aug-2020
Category:	Documents
Upload:	others
View:	0 times
Download:	0 times

PTS ELECTRON - americanradiohistory.com · 2019-07-17 · PTS ELECTRON Precision Tuner Service PIS...

Documents