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42LH90 42LH90

LED Backlights

1080PDirect View LCD

Training

Original February 09, 2010Updated July 28, 2010

LCD DV 42LH902 February 2010

OUTLINEOUTLINE

• Main Board

• Switch Mode Power Supply

Preliminary Section:

Troubleshooting Section: Board Operation Troubleshooting of :

Contact Information, Preliminary Matters, Specifications,LCD Overview, General Troubleshooting Steps, Signal Distribution, Disassembly Instructions and Voltages

• Ft Control Board

• T-CON (TFT Controller) Panel Driver board

• Side Keys

• Inverter Board (LED Backlight Driver)

• Speakers

Disassembly Section: Removal of Circuit Boards


42LH90 LCD Direct View Display

Section 1

This Section will cover Contact Information and remind the Technician of Important Safety Precautions for the Customers Safety as well as the Technician and the Equipment.

Basic Troubleshooting Techniques which can save time and money sometimes can be overlooked. These techniques will also be presented.

This Section will get the Technician familiar with the Disassembly, Identification and Layout of the LCD Display Panel.

At the end of this Section the Technician should be able to Identify the Circuit Boards and have the ability and knowledge necessary to safely remove and replace any Circuit Board or Assembly.

Overview of Topics to be DiscussedOverview of Topics to be Discussed


IMPORTANT SAFETY NOTICEIMPORTANT SAFETY NOTICE

The information in this training manual is intended for use by persons possessing an adequate background in electrical equipment, electronic devices, and mechanical systems. In any attempt to repair a major Product, personal injury and property damage can result. The manufacturer or seller maintains no liability for the interpretation of this information, nor can it assume any liability in conjunction with its use. When servicing this product, under no circumstances should the original design be modified or altered without permission from LG Electronics. Unauthorized modifications will not only void the warranty, but may lead to property damage or user injury. If wires, screws, clips, straps, nuts, or washers used to complete a ground path are removed for service, they must be returned to their original positions and properly fastened.

CAUTIONCAUTION

To avoid personal injury, disconnect the power before servicing this product. If electrical power is required for diagnosis or test purposes, disconnect the power immediately after performing the necessary checks. Also be aware that many household products present a weight hazard. At least two people should be involved in the installation or servicing of such devices. Failure to consider the weight of an product could result in physical injury.

Preliminary Matters (The Fine Print)Preliminary Matters (The Fine Print)


Today’s sophisticated electronics are electrostatic discharge (ESD) sensitive. ESD can weaken or damage the electronics in a manner that renders them inoperative or reduces the time until their next failure. Connect an ESD wrist strap to a ground connection point or unpainted metal in the product. Alternatively, you can touch your finger repeatedly to a ground connection point or unpainted metal in the product. Before removing a replacement part from its package, touch the anti-static bag to a ground connection point or unpainted metal in the product. Handle the electronic control assembly by its edges only. When repackaging a failed electronic control assembly in an anti-static bag, observe these same precautions.

Regulatory InformationRegulatory Information

This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to Part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference when the equipment is operated in a residential installation. This equipment generates, uses, and can radiate radio frequency energy, and, if not installed and used in accordance with the instruction manual, may cause harmful interference to radio communications. However, there is no guarantee that interference will not occur in a particular installation. If this equipment does cause harmful interference to radio or television reception, which can be determined by turning the equipment off and on, the user is encouraged to try to correct the interference by one or more of the following measures: Reorient or relocate the receiving antenna; Increase the separation between the equipment and the receiver; Connect the equipment to an outlet on a different circuit than that to which the receiver is connected; or consult the dealer or an experienced radio/TV technician for help.

ESD NoticeESD Notice (Electrostatic Static Discharge)(Electrostatic Static Discharge)


Customer Service (and Part Sales) (800) 243-0000

Technical Support (and Part Sales) (800) 847-7597

USA Website (GSFS) http://gsfs-america.lge.com

Customer Service Website us.lgservice.com

LG Web Training lge.webex.com

LG CS Academy lgcsacademy.com

Published February 2010 by LG Technical Support and TrainingLG Electronics Alabama, Inc.

201 James Record Road, Huntsville, AL, 35813.

32LG40, 32LH30, 37LH55, 42LG60, 42LG70, 42LH20, 42LH40, 42LH50, 42LH90, 42SL80, 47LG90, 47LH85, 47LE850042PG20, 42PQ20, 42PQ30, 50PG20, 50PJ350, 50PK750, 50PS80, 50PS60, 60PK750, 60PS11, 60PS60, 60PS80

LCD-DV:

PLASMA:

Also available on the Plasma Page:PDP Panel Alignment Handbook, Schematics with Bookmarks

Plasma Control Board ROM Update (Jig required)

LG Contact InformationLG Contact Information

Presentations with Audio/Video and Screen Marks

New Training Materials on New Training Materials on the Learning Academy sitethe Learning Academy site

http://136.166.4.200


Safety and Handling Regulations

1. Approximately 20 minute pre-run time is required before making any picture performance adjustments from the Menu.

2. Refer to the Voltage/Current silk screening on the Switch Mode Power Supply.3. C-MOS circuits are sensitive to static electricity.

Use caution when dealing with these IC and circuits.4. Exercise care when making voltage and waveform checks to prevent costly short circuits

from damaging the unit. 5. Be cautious of lost screws and other metal objects to prevent a possible short in the

circuitry.

1. Check the appearance of the Replacement Panel and Circuit Boards for both physical damage and part number accuracy.

2. Check the model label. Verify model names and board model matches.3. Check details of defective condition and history. Example: Oscillator failure dead set, etc…

Checking Points to be Considered

LCD Direct View OverviewLCD Direct View Overview


Basic Troubleshooting StepsBasic Troubleshooting Steps

Define, Localize, Isolate and Correct

•Define Look at the symptom carefully and determine what circuits could be causing the failure. Use your senses Sight, Smell, Touch and Hearing. Look for burned parts and check for possible overheated components. Capacitors will sometimes leak dielectric material and give off a distinct odor. Frequency of power supplies will change with the load, or listen for relay closing etc. Observation of the front Power LED may give some clues.

•Localize After carefully checking the symptom and determining the circuits to be checked and after giving a thorough examination using your senses the first check should always be the DC Supply Voltages to those circuits under test. Always confirm the supplies are not only the proper level but be sure they are noise free. If the supplies are missing check the resistance for possible short circuits.

•Isolate To further isolate the failure, check for the proper waveforms with the Oscilloscope to make a final determination of the failure. Look for correct Amplitude Phasing and Timing of the signals also check for the proper Duty Cycle of the signals. Sometimes “glitches” or “road bumps” will be an indication of an imminent failure.

•Correct The final step is to correct the problem. Be careful of ESD and make sure to check the DC Supplies for proper levels. Make all necessary adjustments and lastly always perform a Safety AC Leakage Test before returning the product back to the Customer.


This section of the manual will discuss the specifications of the42LH90

LCD Direct View Display

42LH90 PRODUCT INFORMATION SECTION42LH90 PRODUCT INFORMATION SECTION


Basic SpecificationsBasic Specifications

Key TV Features• LED Backlight with Local Dimming• TruMotion 240Hz• Intelligent Sensor• Full HD 1080p• 2,000,000:1 Contrast Ratio• 2.4ms Response Time• 500 cd/m² Brightness• Wide Color gamut• Super IPS Panel• XD Engine• 24fps Real Cinema• ISFccc Ready• Picture Wizard• AV Mode II (Cinema, Sports, Game)• NTSC / ATSC / Clear QAM

• Audio Output Power 10W x 2• Invisible Speaker system• Clear Voice II• SRS TruSurround XT™• Smart Volume Controller• Dolby® Digital 5.1 Decoder• Backlight Control• Video Mute• ENERGY STAR® 3.0 Compliant• 4 HDMI™ v1.3 with Deep Color• SIMPLINK™ Connectivity• 2 HD Component Video Inputs• 2 Composite inputs• 1 Digital Audio Out• USB 2.0 (JPEG, MP3, MP4, Divx)• PC Connectivity (D-Sub 15pin)• RF Antenna Input


Basic Specifications (LOGO Familiarization)Basic Specifications (LOGO Familiarization)

Full HD 1080p Resolution Displays HDTV programs in full 1920 x 1080p resolution for a more detailed picture.


TOP PORTIONBOTTOM PORTION

Remote Control FamiliarizationRemote Control Familiarization p/n MKJ61841701


Accessing the Service MenuAccessing the Service Menu

To access the Service Menu.1) You must have the Service

Remote. p/n 105-201M2) Press “In-Start”3) A Password screen appears.

Note: A Password is required to enter the Service Menu.

Enter; 0000


TV Rear Input / Output JacksTV Rear Input / Output Jacks

Rear In/Out Jacks

USB PortSoftware Upgrades

Music, Photos

Side In/Out

MAIN BOARDRear and Side

Input/Output locations


1) Create an LG_DTV folder on the USB Flash Drive

2) Copy new software (xxx.epk) to "LG_DTV" folder. Make sure to have correct software file.

3) With TV turned on, insert USB flash drive.4) You can see the message

“TV Software Upgrade” (See figure to right)5) Cursor left and highlight "START" Button and

push “Enter” button using the remote control. 6) You can see the download progress Bar.7) Do not unplug until unit has automatically

restarted.8) When download is completed, you will see

“COMPLETE”. 9) Your TV will be restarted automatically.

Software DownloadSoftware DownloadShows the Currently Installed Version

Shows the Software Version

found on the USB Flash

Drive

* CAUTION: Do not remove AC power or the USB Flash Drive. Do not turn off Power, during the upgrade process.

42LH90 Dimensions

7-7/8"200mm

28-3/16"716.28mm

14-1/8"357.98mm

42"1066.8mm

Remove 4 screws to remove stand for

wall mount

16-15/16"430mm

17-7/8"454mm

30-5/8"777.88mm

Center7-7/8"

200mm

9-5/8"244mm

10-5/8"270mm

2-7/16"61.6mm

Weight without Stand: 43 lbWeight with Stand: 51.1 lb

3-11/16"93.98mm

14-3/16"360.68mm

21"533.4mm

14-1/8"357.98mm

16

42LH90 Product Dimensions42LH90 Product Dimensions

There must be at least 4 inches of Clearance on all sides WattageAverage 210WStand By <1W

Model No.Serial No.

Label


DISASSEMBLY SECTIONDISASSEMBLY SECTION

Disassembly:This section of the manual will discuss Disassembly, Layout

(Circuit Board Identification) of the 42LH90 LCD Direct View Television.

Upon completion of this section the Technician will have a better understanding of the disassembly procedures, the layout of the printed

circuit boards and be able to identify each board.


Remove the 23 screws indicated.Pay attention to the size and type of screw

as there are many different types.Putting in an improper screw when reassembling may Cause damage.

The Stand does not need to be removed before removing the back.

Removing the Back Cover Removing the Back Cover

Bottom two screws do not have to be

removed.

Decorative Plastic Cap (if used) must

be removed.


Circuit Board LayoutCircuit Board Layout

POWER SUPPLY

IntelligentSensor / IR

AC Input

Right LEDConnection

Rear Inputs

Power Button

Main Board

Left LEDConnection

Tweeter R

Full Range Speaker R

Tweeter L

Side Keys

MovingLED

LVDS Cables

TFT PanelEAJ60694101

p/n EAY58584001

p/n EBR62151101

p/n EAB58534501 p/n EAB58536001

T-CON boardp/n EAT60665101

Full Range Speaker L

INVERTERp/n EAY60702001

SideInputs

p/n EAD60679428

p/n EAD60679364

T-CON

POWERSUPPLY

MAINBOARD

INVERTER

CN306

P203

P201

SK100SK101

CN1

CN3CN4

CN307 N/C

CN305 N/CCN1 CN2

CN5 CN4

P3500 P3502P3501

P700

P1200P600

Speakers (Front Left)Speakers (Front Right)

AC In

MainPower

IR

LED

KEY B

OA

RD

P100

P101IRP100

P103

J1

42LH90 Connector Identification Diagram42LH90 Connector Identification Diagram

P101N/C

LED

TFT PANEL

20


Power Supply Power Supply Board RemovalBoard Removal

Disconnect P201, P203, AC In SK100 and SK101.

P201

PowerSwitch

Press inTwo tabsto release

lock

P201

SK101

SK100

Remove the 6 screws indicated

by the arrows.

AC In

P203


Remove the 3 Screws in the T-CONshield and remove the shield

CN5 CN4

Disconnect CN1, CN2, CN4 and CN5.See next slide for details about removing cables.

The two screws shown in the picturebelow are for the Service Position.

They would have been removedwhen removing the shield.Be sure to reinstall them ifservicing the T-CON Board.

CN1 CN2

STEP (1)

STEP (2)

TT--CON Board RemovalCON Board Removal

Note: Chocolate (Heat Sink Material)


To remove the LVDS cables CN1 and CN2; Press in on the two tabs and slowly rock the cable out of the connector.

(Shown by the arrows in Figure above)

(CN1) LVDS

Press InPull Out

(CN2) LVDS

Press InPull Out

Press In

TT--CON Board Removal Board Continued (Unlocking CN1 and CN2 LVDS CaCON Board Removal Board Continued (Unlocking CN1 and CN2 LVDS Cables)bles)

Note: The tabs are fragile, use caution, they may break.


To remove the flex cables to the TFT Panel, CN4 or CN5, place a soft thin object like a fingernail underneath the black locking tab and gently pull forward.

(Shown by the arrows in Fig 1 and 2)

Fig 1

Fig 3

Unlocked

Flip the lock up and back from the flex cable. Then the flex cable can be easily removed.

The locking tab is flipped down

CN5 or CN4 Locked

Fig 2

TT--CON Board Removal Board Continued (Unlocking CN4 and CN5 LVDS CaCON Board Removal Board Continued (Unlocking CN4 and CN5 LVDS Cables)bles)


Removing the Main BoardRemoving the Main Board

Remove any tape holding down any cables.

Remove the 6 screws indicated by the arrows.

P600

P700

Flip the locking tab upward, pull the LVDS ribbon out.

NOTE: Always check on top and behind the Large ICs. And look for a piece

of Chocolate(Heat Transfer Material).

Be sure to transfer to new Board if present.

Disconnect P3500, P3501, P3502, P1200,

P700 and P600P3500 P3502

Press in on the top and bottom release

tabs to remove.

P1200

n/c

n/c

Decorative Plastic

(See a and b)

(a)SlideRight

(b)Lift OutPull

Down

P3501

Remove decorative plastic and remove the

board.


Removing the Inverter BoardRemoving the Inverter Board

Remove the 8 screws indicated by the arrows.

Remove the Inverter Shield.

NOTE: Always check for Chocolate(Heat Transfer Material).

Be sure to transfer to new Board if present and replace in the correct position.

There should be 8 pieces on the DC to DC converter coils near the bottom right.

Disconnect CN1, CN3, CN4 and CN306.Remove the Inverter.

CN306

CN4

CN1

CN3

Use caution, do not allow screws to fall.

NOTE: If Servicing the Board, return the screws into the board to provide stability

and grounding.

Inverter

Chocolate


Removing the Inverter Board (Chocolate Notice) Back Side of the Removing the Inverter Board (Chocolate Notice) Back Side of the BoardBoard

On the back side of the Inverter are 5 pieces of

Chocolate, (Heat Transfer and Noise reduction pads). Be sure to replace these on the New Inverter if the board

is replaced.

Be sure they do not fall off if the Inverter is removed.

Chocolate

Chocolate Close Up

Chocolate LocationWhite Box Outline


Removing Front Boards (IR Board and Moving LED Board)Removing Front Boards (IR Board and Moving LED Board)

P100 IR board / Intelligent Sensor

p/n EBR62128101

Moving LED board(Power LEDs)

p/n EBR61674001

p/n EBR62127501

Key board

Disconnect J1 or P100. Remove the LED board by lifting up on the two locking tabs and pull

backwards on the board.

Disconnect P101 and P102. Note P102 is behind the Power Switch.

Remove the IR board by removing the 1 screw and lift out the board.

P101

P102

J1

The Power Switch has been removed for easier

viewing of connectors and screws.

P100Tab

Tab


Removing Front Key BoardRemoving Front Key Board

(A)Push In

p/n EBR62127501

Key Board

To Remove the Key Board, Apply Pressure at

point (A) on the Key Board itself while using an object to slightly pry

out from the top.

Disconnect P100

and remove the Key Board

P100

(B)Push In

Tab

Tab

Apply Pressure at point (B) on the Key Board itself while using an

object to slightly pry out from the bottom.

TabSlots

TabSlots


TROUBLESHOOTING SECTIONTROUBLESHOOTING SECTION

Troubleshooting:This section of the manual will also discuss

troubleshooting.

Upon completion of this section the Technician will have a better understanding of how to diagnosis and resolve

problems.


POWER SUPPLY SECTIONPOWER SUPPLY SECTION

This switch mode power supply develops Stand By 5V at all times when AC is applied.At power on, it develops 12V and 24V for the Main boardAnd 24V for the Inverter.

This power supply draws a little less that 1 watt during stand by mode. The fuse F101 reads 159.9V (from hot ground) during this time.

When the controller chip (IC501) receives the PWR-ON command via P201 Pin 19, the primary section increases its current supplying ability. The Primary fuse F101 now reads 390V.

P201 Connector: (To Main Board)12V is routed out P201 pins 5 and 6 and 24V is routed out P201 pins 1 and 2.

P203 Connector: (To Inverter Board)24V is routed out P203 pins 1 through 5.


There are three types of Main Power switch used in LG televisions.

Type 1: Shuts off AC to the Power Supply.

Type 2: Opens ground to the front IR board. (Stand-By 5V Remains, the Main board stays alive).

This prevents any activity of the IR or the Key Board. When the Switch is opened, a line called Power Key pulls up high when ground opens. When the switch is closed, this same line called Power Key feeds back to the Microprocessor and the Micro. Turns on the Power.

Type 3: Opens ground to the front IR board. (Stand-By 5V turns off, the Main board is dead).

This prevents any activity of the IR or the Key Board. When the Switch is opened, a line called Power Key pulls up high when ground opens. This line feeds back to the Main board and from there it routes to the Power Supply. The high tells the Controller chip to turn off STBY-5V. When the switch is closed, this same line called Power Key now goes high and feeds back to the Power Supply and tells the controller chip to turn STBY-5V on.

Power Supply (Main Power Switch Type 1) LocationPower Supply (Main Power Switch Type 1) Location

On Off

If the TV won’t come on, be sure to check the Main Power Switch before assuming a failure has occurred.

This switch breaks AC to the SMPS.

MAIN POWER SWITCH LOCATIONTYPE 1

(Bottom Left Side viewed from rear)


Hot Ground Shock Hazard

AC INSK101

F1005A/250V

AC IN

N

L

To Master Power SwitchSK101

Components Inside the

dashed line are Hot Gnd

F1013.15A/250VRun 390V

STBY 159.8VFrom Hot Gnd

Pin 1

To MainP201

Power Supply (SMPS) Power Supply (SMPS) Board LayoutBoard Layout

F101 (Diode Check)

Red Lead on Fuse (Open)Black Lead on Hot Ground

Black Lead on Fuse (0.608V) Red Lead on Hot Ground

The Left pin on SK101 goes to the Main Power Switch. The Right hand pin returns

from the Main Power Switch.

POWER SUPPLY (SMPS)Inverter On

Starts the InverterLED Drive Signal

24V B+ forInverter

Stand By 5V

Resets the Microprocessor

MAIN BOARD

PWRInvOn

MstarMicroprocessor

IC100(½)

24VRegulator

12V/24V Regulators

Other Regs

StandBy 5V Reg

1

2

5

66

8

8

6

2

4

42LH90 Power Supply Turn On Sequence42LH90 Power Supply Turn On Sequence

5

5

8

In Stand-By Primary side is

160VIn Run (PWR On)

Primary side is390V

3

24V Audio

12V 24V

8

LVDS12V12V

7

T-CON BOARD

7

LVDS Panel Control

Inv On/Off

Other Circuits

A-DIMNot

Used

P-DIM

Manipulates All Backlight LEDs

IC10039V Reg

9

9

INVERTER

Pow

er On/O

ff

Local Dimming Control Signal

Global Dimming

7

34

IC103, Q106

IC702Reg

3.3V_ST

Remote Power ButtonPower On/Off

12V

T-CON DC-to-DC Converter generates

3.3V 16V 26V -5V

10

Inverter On

P-DIM

24V

Inverter On

LocalDimming

Signal

7

11 Video ArrivesAt point TV is in Stand-By state. Energy Star compliant.Less than 1 Watt

3

MstarIC100

(½)

IC3502Dimming

IC

Cust Menu for BacklightPicture Content

Intelligent Sensor

Q706(½)

LVDS

LVDS

To Panel Left

Side LEDs

To Panel Right

Side LEDs

8AC In

Power Supply will not be on if Main

Power Switch is off.

Main (Master)Power SW

OnOff

L

L

2

4

Relay O

n

Q706 (½)5V Switch

IC10025V_TU Reg

PWM-DIM (PWM Dimming) Manipulates the Backlight Brightness via Customer’s OSD.Manipulates the Backlight Brightness via the Video Processor chip. Darker Picture, Darker Backlights to facilitate improved Contrast Ratio. 0.6V ~ 3.3V Range

42LH90 P700 on Main Board to SMPS Turn On Circuit42LH90 P700 on Main Board to SMPS Turn On Circuit

R189

R185100Ω

100

R7141

R704

C71115pF

P700

11.9V

Gnd

Gnd

Gnd

Gnd

0V

3.2V

5V

1.66V

P201

ERR

PWR

A.DIMINV.On

PWM-DIM

n/c

SMPS

AD12

100Ω

n/c

GndGndGndGnd

Analog Dimming (Fixed Value)

100Ω

H5R245100

SBY5V

MAIN BOARD

5.15V

GndGnd

12V

2

1

4

3

6

5

8

7

10

9

11

12

14

13

16

15

18

17

20

19

22

21

23

24

2

1

4

3

6

5

8

7

10

9

11

12

14

13

16

15

18

17

20

19

22

21

23

24

24.1V24V

GndGnd

GndGndGndGnd

n/c n/c

n/c n/c

L706

L70724V

C72247uF

C7281uF

L70412V

C72168uF

L701

R771 R257

G5R719 10KΩQ702

R713 0Ω

R717 3.3KΩ

P5.3R244 100Ω

+5V_General

INV_CTL

3

1

2

6

5

8

7

Q706

+5VL715

12V_TCON (LVDS 12V)

Q703

R757 0Ω

0.2V 0.6V

4Q705

PANEL_CTL

0.6V

12VR739 47KΩ

R740 47KΩ

AB13

Digital Dimming (Variable)

C726220uF

+5V_ST

L700

R760

0L705

RL_ON

PWM0

PWM2

5V_ST

4.7K

C7251uF

C7061uF

24.1V

4.65V

0Ω

35

Q701

L708

5.2V

n/c

n/c

INV ON/OFF

PWR ON

A-DIM

PWM-DIM

R707 4.7K P5.6

Error Out Stby = 0V Run = 0V

Error=5V: Normal 0V:Micro shuts off

television.

IC100Micro

RL_ON

R201 100Ω

31

Power Det H6

ResetD4

Key 1 A4

Key 2 B4

Power On/OffF6

GPIO-09

R70620K

Error Out

5.15V

5.15V

5.15V

11.9V

Q7040V

E5

100ΩR251R726

10KΩ

L728

+5V_GeneralL709

3.3V_STFrom IC702From

IC103,Q106 Reset


Power Supply Board Low Voltage Test 1Power Supply Board Low Voltage Test 1

AC Should not be applied at any time while adding resistors or while unplugging connectors as damage to the circuit Board may occur.

a) When AC is applied, the SMPS “MUST” be producing STBY 5V on pins 7, 8, 9 or 10 of P201.

If 5V Standby is not being generated, the SMPS is defective andmust be replaced. There is no need to continue with the next test.But, make sure the Main Power Switch is On.

(b) Unplug P700 on the Main Board to make insertion of the Resistors much easier.

TEST 1:

(1) Add a 100Ω resistor between (5V STBY) pin 7, 8, 9 or 10 and Pin 2 (PWR). Apply AC. This will turn on the power supply.a) Check that the 24V and 12V power supplies are

turned on, • P201 (24V pins 17 and 18) • P201 (12V pins 13 and 14)• P203 (24V pins 1 through 5) to the Inverter.

(2) Remove AC power.Use P700

Side to insertresistors

No Backlights during this test


Continue if the 1st test was OK. Leave original resistor in place.

(3) Add another 100Ω resistor between (5V) pin 7, 8, 9 or 10 and Pin 20 (INV On).

(4) Apply AC Power. Simulating a Power and Backlight On command.

Backlights Normal:a) If normal, the backlights should turn on. SMPS OK, Inverter OK.

Backlights Abnormal:a) Recheck all connections.b) Confirm the INV On/Off line pulling up to at least 3V.

REMOVE AC POWER:c) Check the connections to the Inverter.

If the 24V was arriving at the Inverter in Test 1 (pins 1~5 of P203) and the Inverter On command (INV-ON pin 12 of P203) is arriving, then see Inverter Section for further testing.

Power Supply Board Backlights Test 2Power Supply Board Backlights Test 2

P700 Connector disconnected from the Main Board. Apply AC after adding jumper.

Use P700Side to insert

resistors


Diode Mode values taken with all Connectors Removed

1.6V5.0V0VPWR2

GndGndGndGnd4

GndGndGndGnd6

Open5.15V5.15V5.2V8

Open5.15V5.15V5.2V10

GndGndGndGnd12

0.98V11.9V0V12V14

GndGndGndGnd16

0.74V24.1V0V24V18

Open4.65V0VINV.ON20

Open0V0VErr Out22

Open3.2V0V2PDIM24

Diode CheckRun STBYLabelPin

P201 Even "SMPS" to P601 "Main"

Openncncnc1

GndGndGndGnd3

GndGndGndGnd5

Open5.15V5.15V5.2V7

Open5.15V5.15V5.2V9

GndGndGndGnd11

0.98V11.9V0V12V13

GndGndGndGnd15

0.74V24.1V0V24V17

Openncncnc19

Open1.66V0.47V1A.DIM21

Openncncnc23


P201 Odd "SMPS" to P601 "Main"

1ADIM Pin 21 Fixed and not used 2PDIM Pin 24 can vary according to type of signal being processed and the OSD Backlight setting. 0.33V 0% to 3.3V 100%. Output from the Video Processor IC100.

Power Supply Connector P201 Voltage and Diode CheckPower Supply Connector P201 Voltage and Diode Check


Power Supply Connector P203 Voltage and Diode CheckPower Supply Connector P203 Voltage and Diode Check


0.74V24.0V0V24V1~5GndGndGndGnd6~10Open1.66V0.47V1A.DIM11Open4.65V0VINV_ON13Open3.2V*0V2P-DIM13Open0V0VERR14


P203 "SMPS" to CN4 “Inverter"

1ADIM Pin 11 Fixed and not used

2P-DIM Pin 24 can vary according to type of signal being processed and the OSD Backlight setting.

*0.6V 0% to 3.3V 100%. Output from the Video Processor IC100.

P203


Power Supply Connector SK100 and SK101 Voltage and Diode CheckPower Supply Connector SK100 and SK101 Voltage and Diode Check


AC Voltage Readings (From Hot Ground)Pins 1 and 2 for STBY and RUN.

OLNE7

OL120Vac

LE3


OLn/aE5

OL120Vac

n/aE4


SK100 "SMPS" to AC IN SK101 "SMPS" to MASTER POWER SWITCH

SK101 SK100

Bottom Right of SMPS

Live

Neutral

With the Master Power SwitchClosed (On) AC flows.When Open (Off) AC open and does not flow.

F100

F1008A/250V

AC IN

F100 (Diode Check)Main Power Switch Closed

Red Lead on Fuse (Open)Black Lead on Hot Ground

Black Lead on Fuse (0.525V) Red Lead on Hot Ground

E4 E5

E3

E7

AC Voltage Readings for either pin 1 or pin 2 in STBY and RUN with one lead on Neutral of SK100. (Reading from Hot Ground)Note: With Main Power Switch Open, E5 has no AC. E4 does have AC.


INVERTER (LED BACKLIGHTS) SECTIONINVERTER (LED BACKLIGHTS) SECTION

The Inverter receives 24V from the SMPS on CN1 pins 1~5..The Inverter On (INV ON) command from CN1 pin 12 starts the Inverter drive signals.P-DIM is delivered from the Main board through the SMPS to the Inverter on CN1 pin 13.The Inverter is responsible for delivering B+ (27.5V) to each ofthe 64 LED Blocks. This is accomplished by 4 DC to DC Converters (M1~M4) on the board, (easily identified by the 4 yellow capacitors on the lower left of the board.

• M1 and M3 are routed out CN4 • M2 and M4 are routed out CN3.

It also must deliver grounding pulses (Drive Signals) to each of the 64 LED Blocks. This is accomplished by the 32 switching components Q19~Q50 each controlling 2 blocks.

The Left hand connector CN3 connects the 4 LED Boards (32 blocks) on the right side of the screen and the Right hand connector CN4 connects to the 4 LED Boards (32 blocks) on the left.

T-CON

INVERTER

STBY 5V, 12V, 24V

PWR (Power On)Inv On/OffPWM-DIM

24V

P-D

IM

ON/OFF(Inverter On/Off)

VBR-BPWM-DIM

(Global Dimming)

Pulling CN306 will place all LEDs in full bright.

Quad 12 Bit LVDS Video

LVDS 12V

LVDS 12VT-CON develops-5V, 3.3V, 16V, 26V for Panel

PWM-DIM(Global Dimming)

12V24VSTBY 5V

MAIN BOARD

PWR

Relay O

n

LVDS 12V

Quad 12 Bit LVDS Video

To L

ED B

ackl

ight

s

24VINV-ON

Intelligent Sensor(Room Light Monitor) Only affects P-DIM

Customer’s MenuBrightness Selection

Only affects Luminance information

ON/OFF(Inverter On/Off)

IC3502Dimming

Tur-Motion

Luminance Manipulated by the Brightness Setting

Customer’s MenuBacklight Selection Only affects P-DIM

Luminance

I100MstarChip

Backlight setting determines the

Backlight brightness Ceiling

CN1

27.6V

8 LEDsPer/block

DriveSignal

Bright

Medium

Dim

CN4 Controls 4 Boards

Each board controls 2 rows

of 4 Blocks.Total 8 Blocks

DriveSignal

DC Voltage Manipulated by:

Video ContentIntelligent SensorCustomer’s Menu Backlight Setting

Freq: 120Hz

There are two DC to DC converters (27.6V) for each plugCN3/CN4

Called M1-M4

42

42LH90 LED Backlight Controls (Block Diagram)42LH90 LED Backlight Controls (Block Diagram)

P700P201

CN3 Controls 4 BoardsEach board controls 2 rows

of 4 Blocks.Total 8 Blocks

CN1P203

CN306

Drive Signals for CN3 and CN4 going to V1 through V64

(LED Blocks)

P3501

(Pin 1)3.54Vp/p

(Pin 4)3.48Vp/p

(Pin 6)3.46Vp/p

SMPS

CN3

CN4

CN2

CN5 CN4To Panel

CN4/CN5 carry-5V, 3.3V, 16V, 26V and

Video for Panel

12 BitLVDSVideo

IC801XD Engine

12V

Panel C

TL

LocalDimmingControlSignals

12VSwitchQ706

M1-M3

M2-M4

Error

Error

Error

120Hz Backlight Blanking Signal


Inverter Connector IdentificationInverter Connector Identification

CN306

CN4

CN1

M1

Chocolate

M2

M3

M4

CN3

27.5VPower

Supplies

CN305 n/c

CN307 n/c


General LED Backlight Board Information (As viewed from the FronGeneral LED Backlight Board Information (As viewed from the Front)t)

There are 4 LED Boards per/side, 8 Total.There are 2 Rows of LED blocks per/board.

There are 4 LED blocks per/row.


General LED Backlight Block InformationGeneral LED Backlight Block Information

There are 8 LEDs per/block.There are a total of 512 LEDs.

9.4V p/p120 Hz

Connected to CN3 or CN4


LED Backlight Basics (LED Layout)LED Backlight Basics (LED Layout)The picture below shows a close up of one of the 512 individual LEDs contained within the backlight boards. There are two sides each with 256 LEDs (32 blocks) in each side.An individual block is manipulated by the Main board Dimming IC IC3502 in accordance with the video intensity at the specific location of the block of LEDs for that video content (Local Dimming). In other words, if the video is dark in the area of the screen that is being illuminated by a block of LEDs, they will be dimmed.

Also, all blocks are manipulated simultaneously via (Global Dimming) by IC100 Video Processor. The Overall intensity of the backlights is manipulated by the “Global Dimming” signal from the Mstar (IC100) chip called Digital-Dimming (PWM-DIM).

Panel Disassembly required.(Not during warranty period.)A simple Forward Bias diode check will cause the diode to illuminate if it is good. Check any pin on the right to any pin on the left.

A minimum of 21V required to light all 8 LEDs in a blockPins 1,2,13,14,16,17,28,29,31,32,43,44,46,47,58,59

On CN3 and CN4

In the Diode Mode Check, the LED will light. (2.6V Reading)

This represents One Block.There are 4 boards per/side.Each board contains 8 Blocks.Totaling 32 Blocks per/side.64 Blocks over all.


The graphics below show the relationship between the LEDs reaction to real time video on the screen, this is called “Local Dimming”.

Actual Video capture Actual LED reaction capture

(A) (A)(B) (B)(C) (C)

The areas in the picture on the left shown by A, B, C and D show the dark areas of the screen.The picture on the right shows the backlight LEDs. Note they are dimmed out in the same area as the dark video on the left.

To see a representation of the “Local Dimming” the TV has to be set to the “Store Mode”.

Note: These graphics are from the 47LG90 which has more LEDs than the 42LH90, but the explanation remains the same.

LED Backlight Basics (Local Dimming)LED Backlight Basics (Local Dimming)


Inverter Component IdentificationInverter Component Identification


Inverter 27V (M 1Inverter 27V (M 1--M4 Power Supplies) InformationM4 Power Supplies) Information

There are actually 4 power supplies developing the operational B+ (27.5V) for the LED blocks. They are designated as “M1 through M4”.Each of the 4 have the same components.

M1

M2

M3

M4

27.5VTP

Each of the 4 capacitors C12, C27, C212 and C227 have a TP just above the (+) leg of the cap.


Inverter Component Top Half IdentificationInverter Component Top Half Identification

Q35 - Q50Are LED Block Drivers for CN3

Q19 - Q34Are LED Block Drivers fro CN4

D302 blinks at 1Hz when all

is OK

Q19 through Q50Note: Each output driver (switch) has a TP

to the left and right representing a “V”which indicates a Block of LEDs.

In the example Q35 above; V34 represents Pin 23 of CN4V33 represents Pin 24 of CN4

Grounding these points when the 27.6V supplies are working will cause the entire

Block of Backlight LEDs to turn on.(100mA to light one block)

Example

CN327.5V Line on CN3

Pins 1-2 (Out_M2)Pins 13-14 (Out_M2)Pins 16-17 (Out_M2)Pins 26-29 (Out_M2)Pins 31-32 (Out_M4)Pins 43-44 (Out_M4)Pins 46-47 (Out_M4)Pins 58-59 (Out_M4)



Local Dimming Control SignalsTo P306 from Main

Example: Q35

Voltage Supplies to each connector.


Inverter LED D302 InformationInverter LED D302 InformationLED D302

LED D302 blinks at 1Hz to indicate that the Inverter is running correctly.

When it blinks at any other rate, it indicates there is an abnormal state of the Inverter.

When it doesn’t blink, check the 24V arriving at the board on CN1 pins 1~5.Check the two fuses F1 and F2 for 24V.Check IC302 and IC303 regulator voltages (see page 56).


Inverter Fuse F1 and F2 CheckInverter Fuse F1 and F2 Check

F12A/125VCenter of the Board

Left of CN1 Connector

F1 or F2 (Diode Mode Check)Open (Red Lead on Fuse)

0.46V (Black Lead on Fuse)

F212A/65V

F1 or F2Normal 24V in Run


Inverter Crystal Y301 InformationInverter Crystal Y301 Information

Crystal Y301


Inverter 27V (M 1Inverter 27V (M 1--M4 Power Supplies) ChecksM4 Power Supplies) Checks

Example of M3 (27.5V) Power SupplyThere are actually 4 power supplies developing 27.5V for the LED blocks. They are designated as “M1 through M4” This one is M3. Each of the 4 have the same components.

Q4, Q5, Q11, Q11, Q12, Q204, Q205, Q211, Q212

Gnd 3.67V

23.9V

D2, D3, D7, D8, D202, D203, D207, D208

Gnd26.4V28.0V Gnd

3.74V 3.73VGnd 4.0V 6.75V 4.0V

Q2, Q10,Q202, Q210

Q3, Q09Q203, Q209


Inverter IC2, IC4 and IC15 ChecksInverter IC2, IC4 and IC15 Checks

Center of the Board

GND

IC2

4.6V GND

GND

1.0V 7V

24V

IC4

IC15

3.29V

6.99V

0.46V

1.71V

6.95V


Inverter IC303 and IC302 Checks (Controller IC301 B+)Inverter IC303 and IC302 Checks (Controller IC301 B+)

Top of the Board

GND

IC303

GND

IC302

7.0V

3.3V

7.0V

1.8V


Inverter Board Connector CN3, CN4 to the Panel (Voltage and DiodInverter Board Connector CN3, CN4 to the Panel (Voltage and Diode Check)e Check)

OPEN0Vn/c60OPEN27.0VOut_M458~59OPEN0Vn/c57OPEN0.7-1.2VV61~V6453~56OPEN0.7-1.2VV56~V5349~52OPEN0Vn/c48OPEN27VOut_M446~47OPEN0Vn/c45OPEN27VOut_M443~44OPEN0Vn/c42OPEN0.7-1.2VV45~V4838~41OPEN0.7-1.2VV40~V3734~37OPEN0Vn/c33OPEN27.0VOut_M431~32OPEN0Vn/c30OPEN27.0VOut_M228~29OPEN0Vn/c27: n/cOPEN0.7-1.2VV29~V3223~26OPEN0.7-1.2VV24~V2119~22OPEN0Vn/c18OPEN27.0VOut_M216~17OPEN0Vn/c15OPEN27.0VOut_M213~14OPEN0Vn/c12OPEN0.7-1.2VV13~V168~11OPEN0.7-1.2VV8~V54~7OPEN0Vn/c3OPEN27.0VOut_M21~2

ResistanceRunLabelPin

OPEN27VOut_M31~2OPEN0Vn/c3OPEN0.7-1.2VV57~604~7OPEN0.7-1.2VV52~V498~11OPEN0Vn/c12OPEN27.0VOut_M313~14OPEN0Vn/c15OPEN27.0VOut_M316~17OPEN0Vn/c18OPEN0.7-1.2VV41~V4419~22OPEN0.7-1.2VV34~V3323~26OPEN0Vn/c27OPEN27.0VOut_M328~29OPEN0Vn/c30OPEN27.0VOut_M131~32OPEN0Vn/c33OPEN0.7-1.2VV25~V2834~37OPEN0.7-1.2VV20~V1738~41OPEN0Vn/c42OPEN27.0VOut_M143~44OPEN0Vn/c45: n/cOPEN27.0VOut_M146~47OPEN0Vn/c48OPEN0.7-1.2VV9~V1249~52OPEN0.7-1.2VV4~V153~56OPEN0Vn/c57OPEN27VOut_M158~59OPEN0Vn/c60

ResistanceRunLabelPin

CN3 Inverter to Panel CN4 Inverter to Panel

Note 46-47Incorrect

Silk Screening on Board.

Inverter Run voltages taken

with built in test pattern full

white screen



Inverter Board Connector CN1 to the P203 Inverter Board Connector CN1 to the P203 ““SMPSSMPS”” (Voltage and Diode Check)(Voltage and Diode Check)

2.9V24.0V0VVIN1

2.9V24.0V0VVIN2

2.9V24.0V0VVIN3

2.9V24.0V0VVIN4

2.9V24.0V0VVIN5

GNDGNDGNDGND6

GNDGNDGNDGND7

GNDGNDGNDGND8

GNDGNDGNDGND9

GNDGNDGNDGND10

OPEN1.66V0.47VNC11

1.6V4.65V0VON/OFF12

OPEN0.33V-3.2V0VExt_VBR_B13

OPEN0V0VAGP14

Diode ModeRun STBYLabelPin

CN1 Connector “Inverter” to P203 “SMPS”

Inverter Run voltages taken with built in test pattern full white screen


P-DIM

Ext_VBR_B(P-DIM) Pin 13

can vary according to type

of signal being processed and

the OSDBacklight setting.

0.33V 0% to 3.3V 100%.

Output from the Video Processor

IC100.

Error


Inverter Board Connector CN306 to the P3501 Inverter Board Connector CN306 to the P3501 ““MainMain”” (Voltage and Diode Check)(Voltage and Diode Check)

CN306 Connector “Inverter” to P3501 “Main”

OPEN0.02V0VScel1

OPEN0V0VNC2

OPEN0V0VNC3

OPEN0.7 TO 3.0V*0V*Din4

OPEN0V0VGND5

OPEN0V0VDclk6

OPEN0V0VGND7

GND0V0VGND8

ResistanceRun STBYLabelPin

* Local Dimming Off 0.85V

Inverter Run voltages taken with built in test pattern full white screen



LCD Panel Controller BoardThe T-Con Processor UC1 receives from the Main Board via CN1 dual 12 Bit LVDS (Video) Signals and CN2 dual 12 Bit LVDS (Video) Signals. Both LVDS cables are carrying 24 bit signals.

UC1 then processes these signals into TFT Drive Signals. It delivers its output signals through connectors CN4 and CN5 to drive the LCD Panel.

12V is supplied to the T-Con Board on connector CN1 from the Main Board(easily measured at fuse F1).

There is one regulator that creates 1.8V developed at pin 2 (Center Leg) of U11.

U5 is a DC to DC converter IC which develops the Panels driver voltages. 16V, 3.3V, -5V and 26V.

These voltages can be read at the ribbon connector or at test points on the board which will be identified later.

TT--CON (TFT DRIVE) BOARD SECTIONCON (TFT DRIVE) BOARD SECTION


TT--CON (TFT Drive) Board (Shield Removed)CON (TFT Drive) Board (Shield Removed)

F1

CN5 CN4

UC1

ToMain Board

To TFT Panel To TFT Panel

Remember to replace screws for ground purposes if testing the Board.

T-CON p/n: EAT60665101

CN1 CN2

U12

U11 U5

D9

D10

D8

D7

U10

Q1

FL2

FL1

42LH90 T-CON (TFT Drive) Board Drawing (Components and Voltages Identified)42LH90 T-CON (TFT Drive) Board Drawing (Components and Voltages Identified)

62

P/N EAT60665101

TO TFT MODULE

125V / 3A

CN5 CN4

TO TFT MODULE

UC1

FL1

D8

L1

F1 (12V)

TO TFT MODULE

T-CON(TFT Driver)

Gnd Protect

FL2Gnd Protect

CN1

U11

D7

L2D9

D10

Q1

U12

U10

Pin 2Pin 4

Pin 56,57,58Pin 53,54

U5

1) 0V2) 1.19V3) 3.3V B

2.78VE

3.3V

C3.3V

16V

20.5V 14.25V

-2.4V

12

32

R701R702

R70

4R

705

R70

6

16V26V

27V

26V16V -4.9V3.3VPin 59

Pin 57Pin 3,4,5

Pin 7,826V16V-4.9V3.3V

C74

4R

721

( 12V )

U5

Gnd -4.9V

U5 B+ ( 12V )

3.3VVCC

16V

3.3V

CN2

VDD1) Gnd2) Gnd3) Gnd4) Gnd

8) 3.34V7) 3.09V6) 3.34V5) 3.34V

12V LVDS Pins 48~51


TT--CON (TFT Drive) Board ChecksCON (TFT Drive) Board Checks

Check Fuse F1 for 12V from CN1 Pins 48~51

Check the Regulator U11 for Correct Voltage

T-CON Board

0V

3.3V

1.8V

CN1

F1

U11

U11 has a piece of “Chocolate” which is heat

transfer material. Transfer if board is replaced.

F1 (Diode Mode Check)Open (Red Lead on Fuse)

0.46V (Black Lead on Fuse)


T-CON Board

-5VSource

D9 Anode

26VSourcePin 8

16V (VDD)Pin 42

3.3V TPVCC

3.3V Source Pin 23, 24

16V (D6)Not for Panel Cathode

16.9V

D7Cathode 3.3V

12VPin 37,38Chip B+

TT--CON (TFT Driver) Board CN4 and CN5 (Voltage Sources)CON (TFT Driver) Board CN4 and CN5 (Voltage Sources)

12VPin 25,26Chip B+

D7

U5


CN5 CN4

T-CON Board

CN5 CN4

-5VPin 59

26VPin 57

16VPin 3,4,5

3.3VPin 7,8

16VPin 56,57,58

3.3VPin 53,54

-5VPin 2

26VPin 4

TT--CON (TFT Driver) Board CN4 and CN5 (Voltage Check)CON (TFT Driver) Board CN4 and CN5 (Voltage Check)


TT--CON Board Connector CN1 to the Main Board (Voltage and Diode ChCON Board Connector CN1 to the Main Board (Voltage and Diode Check)eck)Diode Mode values taken with all Connectors RemovedCN1 “T-CON“ to P3500 CONNECTOR "Main"

Diode TestRunLabelPin

Open1.26VURSA-ACKM20

Open1.25VURSA-ACKP19

GndGndGnd18

Open1.4VURSA-A2M17

Open1.4VURSA-A2P16

Open1.2VURSA-A1M15

Open1.3VURSA-A1P14

Open1.2VURSA-A0M13

Open1.3VURSA-A0P12

Openn/cOPC-Out211

Openn/cOPC-EN10

Openn/cOPC-Out9

Openn/cPWM-DIM*8

Gndn/cLVDS-Sel7

n/cn/cn/c6

n/cn/cn/c5

n/cn/cn/c4

n/cn/cn/c3

n/cn/cn/c2

GndGndGnd1


Open1.44VURSA-B4P40

Open1.21VURSA-B3M39

Open1.2VURSA-B3P38

GndGndGnd37

Open1.22VURSA-BCKM36

Open1.21VURSA-BCKP35

GndGndGnd34

Open1.22VURSA-B2M33

Open1.21VURSA-B2P32

Open1.1VURSA-B1M31

Open1.4VURSA-B1P30

Open1.1VURSA-B0M29

Open1. 4VURSA-B0P28

n/cn/cn/c27

GndGndGnd26

Open1.1VURSA-A4M25

Open1.4VURSA-A4P24

Open1.1VURSA-A3M23

Open1.4VURSA-A3P22

GndGndGnd21


Open12VLVDS 12V51

Open12VLVDS 12V50

Open12VLVDS 12V49

Open12VLVDS 12V48

n/cn/cn/c47

GndGndGnd46

GndGndGnd45

GndGndGnd44

GndGndGnd43

GndGndGnd42

Open1.09VURSA-B4M41


TT--CON Board Connector CN2 to the Main Board (Voltage and Diode ChCON Board Connector CN2 to the Main Board (Voltage and Diode Check)eck)Diode Mode values taken with all Connectors RemovedCN2 “T-CON“ to P3502 CONNECTOR "Main"


Open1.3VURSA-C3P20

GndGndGnd19

Open1.23VURSA-C2M18

Open1.23VURSA-C2P17

GndGndGnd16

Open1.2VURSA-C2M15

Open1.3VURSA-C2P14

Open1.2VURSA-C1M13

Open1.3VURSA-C1P12

Open1.2VURSA-C0M11

Open1.28VURSA-C0P10

GndGndGnd9

n/cn/cn/c8

n/cn/cn/c7

n/cn/cn/c6

n/cn/cn/c5

n/cn/cn/c4

n/cn/cn/c3

n/cn/cn/c2

n/cn/cn/c1


GndGndGnd41

GndGndGnd40

Open1.15VURSA-D4M39

Open1.4VURSA-D4P38

Open1.25VURSA-D3M37

Open1.3VURSA-D3P36

GndGndGnd35

Open1.29VURSA-DCKM34

Open1.23VURSA-DCKP33

GndGndGnd32

Open1.2VURSA-D2M31

Open1.3VURSA-D2P30

Open1.3VURSA-D1M29

Open1.29VURSA-D1P28

Open1.25VURSA-D0M27

Open1.29VURSA-D0P26

GndGndGnd25

GndGndGnd24

Open1.18VURSA-C4M23

Open1.13VURSA-C4P22

Open1.2VURSA-C3M21


MAIN BOARD SECTIONMAIN BOARD SECTION

The Main board receives its operational B+ from the Power Supply via P400. There are two LVDS cable feeds that go to the T-CON (TFT Driver) section. These carry the duel 12 bit LVDS Video signals and the TruMotion 60Hz duel 12 bit LVDS. These signals have already been prepared for the T-CON board. The Main board also includes the Tuner, Audio and Audio/Video inputs and selection circuits.

STAND-BY• STBY 5V pins 7~10

The Main board also develops several B+ sources on the board.

LVDS• LVDS 12V (Not generated, but switched

from the 12V arriving from the SMPS. AUDIO• 3.3V• 1.8V

Mstar IC100 Video and Micro Processors• 1.2V

IC3502 Tru-Motion and Dimming IC.• 1.26V_MEMC, 1.8V_MEMC,

1.8V_DDR, and 3.3V

RUN • 12V pins 13 and 14 • 24V pins 17 and 18.

TUNER and VSB CIRCUIT • 9V which is used to make 5V TU • 5V TU• 3.3V• 1.2V

STAND-BY VOLTAGES• 3.3V_ST

GENERAL• 5V_General• 5V_EXT

Input Voltages from SMPS.


Main Board LayoutMain Board Layout

VIDEO PROCESSOR

IC100 and Tru-Motion IC3502

runs Hot. This is normal.

P3501to Inverter

SW3500Not

used

X100

P3500

SW100Reset

IC100Micro/VideoProcessor

X800

IC3502Dimming

Tru-Motion

P600to Speakers

P1200to IR Board

TunerTU1001

n/c

HDMISelector

DDR

DDR

P700to SMPS

IC600Audio

IC801

X3500

USB

Rear Inputs

To Panel

P3502

70

P3500

IC3502Tru-

Motion/Dimming

P3502

IC3502 Operates at high temperature

P3501

P700

X350025Mhz

IC3503

IC3504

IC3500

Q706

E

C

B

Q702

IC706

E

C

BQ701

L718

L710

IC701

L726

IC705

IC704

IC2

SW3500Not Used

XDEngine

IC801

IC901

IC900

X80012Mhz

IC1

X10012Mhz


Mstar

IC707

L712IC708

IC1000IC1001

IC101

SW100

EC B

Q100

IC105

IC502IC600

L607

L606

P1200E

C B

Q106

IC1002

Q1200

ECB

IC1203

TU1001 TunerTDVW-H103F

(1)

Analog Video (19)

Tuner 5V_TU (4)

Data (8)Clock (9)

Dig DIF+ (12)Dig DIF- (13)

SIF (16)

X100525Mhz

P101N/A

IC1004

D1000

12V LVDSPins 1~4

P600

42LH90MAIN

BOARD

42LH90Main Board (Front Side)

Component Layout

42LH90Main Board (Front Side)

Component Layout

42LH90 Main (Front Side) Component VoltagesIC101 Serial Flash IC705 +1.26V_VDDC IC1000 +1.26V_PVSB IC3503 +1.8V Reg Q706 +5V/12VLVDS

Pin Memory Pin Regulator Pin Regulator Pin Dimming Pin Switch[1] 0.05V [1] 0.8V [1] 0V [1] 0.58 [1] 5.1V[2] 3.2V [2] Gnd [2] 3.39V [2] 1.8V [2] 0.29V[3] 2.5V [3] 5V [3] 3.4V [3] 3.19V [3] 11.9V[4] Gnd [4] 6V [4] 0V [4] 5.99V[5] 0V [5] 3.2V [5] 0V IC3204 Dimming [5] 11.98V[6] 0V [6] 1.2V [6] 1.21V Pin EEPROM [6] 11.98V[7] 3.3V [7] 1.26V [7] 0.8V [1] Gnd [7] 5.06V

[8] 3.3V [8] 5V [8] Gnd [2] Gnd [8] 5.06V[3] Gnd

IC105 HDCP IC706 5V_EXT IC1001 +3.3V_PVSB [4] Gnd Q1200 IR RS232Pin EEPROM Pin Memory Pin +3.3V_FE [5] 3.3V Pin Buffer[1] Gnd [1] 0.8V [1] 4.94V [6] 3.3V B 0.634V[2] Gnd [2] Gnd [2] 4.94V [7] 0V C 0.97V[3] 3.29V [3] 12V [3] Gnd [8] 3.3V E Gnd[4] Gnd [4] 9.6V [4] 3.4V[5] 3.3V [5] 5V [5] 1.25V Q100 W/P IC101 D1000 Speed Up Reset[6] 3.3V [6] 4.97V Pin Pin IC1004[7] 0V [7] 4.97V IC1002 +5V_TU B 0V C 3.4V

[8] 3.3V [8] 1.9V Pin Tuner C 2.5V A 3.38V[1] 8.92V E Gnd

IC701 +1.8V_DDR IC707 +1.8V_MEMC [2] 1.88VPin Regulator Pin Regulator [3] 5.04V Q106 S5/S6 Reset[1] 0V [1] 0.8V [4] 0V Pin Mstar[2] 3.2V [2] Gnd [5] Gnd B 0V[3] 3.2V [3] 4.92V C 3.28V[4] n/c [4] 6.5V IC1203 SPIF Optical E 0V[5] n/c [5] 4.8V Pin Audio[6] 1.8V [6] 1.8V [1] 1.58V Q702 INV_ON[7] 0.8V [7] 1.8V [2] 3.2V Pin Inverter

[8] Gnd [8] 4.8V [3] Gnd B 0.05V[4] 1.61V C 4.66V

IC704 +3.3V_FE IC708 +1.26V_MEMC [5] 3.21V E GndPin Regulator Pin Regulator[1] 0.8V [1] Gnd IC3500 +3.3V_Dimming[2] Gnd [2] 0.8V Pin Regulator[3] 5V [3] 1.26V [1] Gnd[4] 7.5V [4] 1.26V [2] 3.3V[5] 5V [5] 1.8V [3] 5V[6] 3.3V [6] 5V[7] 3.3V [7] 1.26V

[8] 2.1V [8] 5V

71

42LH90Main Board (Back Side)

Component Layout

42LH90Main Board (Back Side)

Component Layout

72

1

TUN

ER TU

1001

(5V) 4TD

VW-H

103F

13 DIF -12 DIF +

16 SIF

19 Video

IC3505

C

A1

A2

D1223

IC1200

IC1201

D500

C

A1A2

EC B

Q1001 EC B

Q1000

IC1003IC703

ECB

C

A1

A2

EC B

23 1

Q105

IC103

IC702IC104

FLAS

H

IC102

IC800

IC1202

IC501

Q703 E CBQ704 E CBQ705 E CB

IC1072

3

1

Q600

D102

42LH90 MAIN BOARD(Back View)

42LH90 Main (Back Side) Component VoltagesIC103 Reset Gen IC1003 9V Reg IC3505 Reset Gen Q1001 Tuner Video

Pin Mstar IC100 Pin to IC1002 Pin for IC3502 Pin Buffer[1] Gnd [1] 12V [1] 3.3V B 3.09V[2] 0V [2] Gnd [2] Gnd C 0V[3] 3.3V [3] 8.9V [3] 3.22V E 3.72V

For Tuner Voltage 5VIC104 RGB (PC) Q105 PWR On Delay D102 Audio Mute

Pin EEPROM IC1200 RGB Pin Q2405 Pin Routing[1] Gnd Pin EEPROM B 0V A1 0.047V[2] Gnd [1] Gnd C 1.95V C 0.089V[3] Gnd [2] Gnd E Gnd A2 0V[4] Gnd [3] Gnd[5] 3.22V [4] Gnd Q600 Audio Mute D500 Shunt for[6] 3.22V [5] 4.82V Pin Switch Pin IC501[7] 0V [6] 4.82V B 0.08V A1 3.25V[8] 3.22V [7] 4.82V C 3.26V C 3.12V

[8] 4.82V E Gnd A2 0VIC107 Power Det

Pin Gen IC1201 RS232 Q703 5V Switch D1223 5V Routing[1] Gnd Pin Rx/Tx Pin Control Pin for IC1200[2] 3.9V [1] 3.3V B 0.6V A1 0V[3] 3.28V [2] 5.56V C 0.03V C 4.82V

[3] 0.02V E Gnd A2 5.11VIC702 +3.3V_ST [4] 0.03V

+3.3V_AVDD_MPLL [5] 5.46V Q704 12V LVDSPin Regulator [6] 5.5V Pin Switch Control[1] Gnd [7] 5.5V B 0.05V[2] 3.29V [8] 0V C 0.65V[3] 5.11V [9] 3.29V E Gnd

[10] 3.24VIC703 +3.3V_ST [11] 0.02V Q705 12V LVDS

Pin Regulator [12] 3.29V Pin Switch[1] 0V [13] 0V B 0.65V[2] 1.8V [14] 5.5V C 0.0V[3] 3.21V [15] Gnd E Gnd

[16] 3.29VQ1000 Tuner SIF

IC800 SPI Flash IC1202 USB +5V Pin BufferPin Pin Switch B 2.4V[1] 0.12V [1] 4.95V C 0V[2] 1.13V [2] Gnd E 3.85V[3] 3.26V [3] 3.21V[4] Gnd [4] 4.95V[5] 0.06V [5] 0V[6] 1.2V [6] 4.95V[7] 3.27V [8] 3.27V

31 2

3

73


Main Board X100 and X800 Crystal ChecksMain Board X100 and X800 Crystal Checks

2.56Vp/p 12MhzSet on or off. Use bottom leg.

IC100 Microprocessor Crystal

MAIN Board

X100

X800

Set on. Use bottom leg.2.25Vp/p 12Mhz

IC800 XD Engine Crystal

1.58V

1.51V

1.54V

1.59V


Main Board X3500 and X1005 Crystal CheckMain Board X3500 and X1005 Crystal Check

3.94Vp/p 25Mhz Set on. Use Left leg.

IC3502 Dimming IC Crystal

MAIN Board

X1005

Set on. Use Top leg.3.54Vp/p 25Mhz

IC1005 Tuner Control IC Crystal

X3500

1.64V

1.54V

Dimming/Tru-Motion

1.54V 1.57V

5.67Vp/p25MhzBottom

Leg

5.34Vp/p 25MhzRight Leg


Main Board LD1000 FunctionMain Board LD1000 Function

Main BoardLD1000 Location

Use LD1000 as a visual aid.This lets you know the PLL (Phase Lock Loop)

circuit is working correctly in IC1004.This indicates the Tuner Crystal is Locked to the

Reference frequency in IC1004.

LD1000


Main Board Connector P700 to Power Supply Voltage and Diode ChecMain Board Connector P700 to Power Supply Voltage and Diode Checkk


2.6V5V0VPWR-ON2GndGndGndGnd4GndGndGndGnd61.1V5.15V5.15V5.2V81.1V5.15V5.15V5.2V10GndGndGndGnd122.2V12V0V12V14GndGndGndGnd16Open24V0V24V182.9V4.65V0VInv_On20Open0V0VErr Out221.3V2.43V0V2PDIM24


Openncncnc1GndGndGndGnd3GndGndGndGnd51.1V5.15V5.15V5.2V71.1V5.15V5.15V5.2V9GndGndGndGnd112.2V12V0V12V13GndGndGndGnd15

Open24V0V24V17Openncncnc19Open1.66V0.47V1A.DIM21Openncncnc23


1ADIM Pin 21 Fixed and not used.It is an Open connection on the Inverter Board.

2PDIM Pin 24 can vary according to type of signal being processed, OSD Backlight setting. 0.6V 0% to 3.3V 100% and the Intelligent Sensor. Output from the Video Processor IC100.

P700 “Main Board" to P201 “SMPS"Odd Pins Even Pins

P700


Main Board Connector P3500 to the TMain Board Connector P3500 to the T--CON Voltage and Diode CheckCON Voltage and Diode CheckDiode Mode values taken with all Connectors RemovedP3500 CONNECTOR “Main" to “T-CON“ CN1

0.87V1.4VLVDS_CH2_C-20

1.23V1.13VLVDS_CH2_C+19

GndGndGnd18

1.25V1.21VLVDS_CH2_CLK-17

1.14V1.22VLVDS_CH2_CLK+16

GndGndGnd15

1.23V1.44VLVDS_CH2_D-14

1.23V1.09VLVDS_CH2_D+13

0.875V1.44VLVDS_CH2_E-12

1.23V1.09VLVDS_CH2_E+11

GndGndGnd10

GndGndGnd9

GndGndGnd8

GndGndGnd7

GndGndGnd6

n/cn/cn/c5

Open12VLVDS 12V4

Open12VLVDS 12V3

Open12VLVDS 12V2

Open12VLVDS 12V1


1.05V1.3VLVDS_CH1_A-40

1.18V 1.2VLVDS_CH1_A+39

1.23V1.3VLVDS_CH1_B-38

1.11V 1.2VLVDS_CH1_B+37


0.88V1.4VLVDS_CH1_C+35

GndGndGnd34



GndGndGnd31

1.23V1.4VLVDS_CH1_D-30

1.23V1.1VLVDS_CH1_D+29

1.23V1.4VLVDS_CH1_E-28

0.87V1.1VLVDS_CH1_E+27

GndGndGnd26

n/cn/cn/c25

0.88V1.4VLVDS_CH2_A-24

1.22V1.1VLVDS_CH2_A+23


0.87V1.1VLVDS_CH2_B+21


GndGndGnd51

Openn/cn/c50

Openn/cn/c49

Openn/cn/c48

Openn/cn/c47

Openn/cn/c46

Openn/cLVDS-Sel45

Openn/c*PWM-DIM44

Openn/cOPC-Out43

1.09Vn/cOPC-EN42

GndGndGnd41


PWM-DIM (Pin 44) is Open on the Main Board.

1

P3500


Main Board Connector P3502 to the TMain Board Connector P3502 to the T--CON Voltage and Diode CheckCON Voltage and Diode CheckDiode Mode values taken with all Connectors RemovedP3502 CONNECTOR “Main" to “T-CON“ CN2

1.07V1.13VLVDS_CH3_E-20

1.08V1.18VLVDS_CH3_E+19

GndGndGnd18

GndGndGnd17

0.87V1.29VLVDS_CH4_A-16

1.23V1.25VLVDS_CH4_A+15

0.87V1.29VLVDS_CH4_B-14




GndGndGnd10



GndGndGnd7



1.24V1.4VLVDS_CH4_E-4

1.18V1.15VLVDS_CH4_E+3

GndGndGnd2

GndGndGnd1


GndGndGnd41

n/cn/cn/c40

n/cn/cn/c39

n/cn/cn/c38

n/cn/cn/c37

n/cn/cn/c36

n/cn/cn/c35

n/cn/cn/c34

GndGndGnd33

0.87V1.28VLVDS_CH3_A-32

1.20V1.2VLVDS_CH3_A+31





GndGndGnd26



GndGndGnd23



Diode TestRunLabelPin 1P3502


Main Board Connector P1200 to (Ft. IR/Intelligent Sensor) VoltagMain Board Connector P1200 to (Ft. IR/Intelligent Sensor) Voltage and Diode Checke and Diode Check


P1200 CONNECTOR "MAIN Board" to P101 "Front IR / Intelligent Sensor Board"

Open3.2V0VPWR On120.67V3.2V3.2V3.3V_ST11OpenGndGndGnd10Open3.5V3.5VIR9GndGndGndWARM_ST8GndGndGndGnd71.1V5.1V5.1V5V_ST61.0V3.2V3.2VKey251.0V3.2V3.2VKey14GndGndGndGnd31.6V3.2V0.57VSDA21.6V3.2V0.57VSCL1

Diode CheckRun STBYLabelPinP1200

1


Main Board Connector P600 to Speakers Voltage and Diode CheckMain Board Connector P600 to Speakers Voltage and Diode Check


P400 CONNECTOR "Main" to "Speakers"

SPK-L(+)SPK-L(-)SPK-R(+)SPK-R(-)LABEL

2.63V12V0V42.63V12V0V32.63V12V0V22.63V12V0V1

Diode CheckRunSBYPin

Use speaker out to test for defective Audio Amp IC600Note: (Normal, ½ Audio B+)

P600

Q600Back of board

Audio B+24V

Pins 49-52

MutePin 25

Q400 (Mute) Active Low. Normal 3.3V Collector to Pin 25

IC600 Mute Driver


FRONT (IR, INTELLIGENT SENSOR and MOVING LED) SECTIONFRONT (IR, INTELLIGENT SENSOR and MOVING LED) SECTION

The Intelligent Sensor and IR board (located on the bottom left as viewed from the rear) contains the IR (Infrared Remote Sensor) and the Intelligent Sensor. This board also connects with the Side Key Board and the Moving LED board which contains the 10 front Power LEDs.

The IR board receives it operating B+ via P101 pin 6 (STBY 5V) and pin 11 (3.3V) from connector P1200 on the Main board.

The Intelligent Sensor communicates with the Micro/Video Processor IC100 Mstar Chip via clock and data lines SCL1 and SDA1 (AA17 and AA18) arriving on connector P101 from P700 pins 1 and 2 on the Main board.

The Front Power LEDs are controlled by these same Clock and Data lines which communicate with the LED Driver IC U1 on the Moving LED board.

The IR pulses (5V p/p) P101 pin 9 are sent to P1200 on the Main board and on to the Microprocessor (IC100) via pin C4.

The Key board is routed to the IR board via P100 to P102 on the Key 1 and Key 2 lines, (Key 1 pin 1 and Key 2 pin 3). Then out P101 pins 4 and 5 to P1200 on the Main Board. Then to the Microprocessor A4 and B4 lines.


Front Boards (Connections Identified)Front Boards (Connections Identified)

P100

P100

P101

Intelligent Sensor / IR board

p/n EBR62128101

P102

Moving LED board(Power LEDs)

p/n EBR61674001

p/n EBR62127501

Key board

J1


Front Moving LED Board IdentifiedFront Moving LED Board Identified

The Front LED Board (located on the bottom left as viewed from the rear)

Contains the front Power LEDs.

Power LEDs

J1 ConnectorTo Intelligent

Sensor and IR Board

U1LED Driver

Pin 1


Front Board Connectors P101 and P2 Voltage and Diode CheckFront Board Connectors P101 and P2 Voltage and Diode Check


P101 CONNECTOR "Front IR / Intelligent Sensor" to P1200 " MAIN Board "

Open3.2V0VLED On12Open3.2V3.2V3.3V11GndGndGndGnd10Open3.5V3.5VIR9OpenGndGndWarm_ST8GndGndGndGnd7

Open5.1V5.1VST_5V6Open3.2V3.2VKey25Open3.2V3.2VKey14GndGndGndGnd3Open3.2V0.57VSDA2Open3.2V0.57VSCL1

DiodeCheckRun STBYLabelPin

P2 Connector to “Side Key" P100

Gnd

Open

Gnd

Open

DiodeCheck

GndKey 2Gnd

Key 1

Label

GndGnd43.2V3.2V3GndGnd232V3.2V1

Run STBYPin


Front Board Connector P100 and J1 Voltage and Diode CheckFront Board Connector P100 and J1 Voltage and Diode Check


P100 CONNECTOR "Front IR / Intelligent Sensor" to J1 "Moving LED Board"

Open0V0V8Open*3.27V*0V7GndGndGnd6

Open5V0.75V5GndGndGnd4

Open4.9V0.59V3GndGndGnd2

Open5V5V1

DiodeCheckRun STBYPin

*Pin 7: From Pin 12 of P101 IR boardFrom Pin 12 of P1200 Main boardFrom R196 Main boardFrom Pin GPIO96 of Micro IC100

J1 "Moving LED Board"P100 CONNECTOR "Front IR / Intelligent Sensor"

Open8Open7Gnd6Open5Gnd4Open3Gnd2Open1

DiodeCheckPin

Pin 7: From Pin 7 of P100

See P100Table for Voltages


SIDE KEY BOARD SECTION p/n EBR62127501SIDE KEY BOARD SECTION p/n EBR62127501

SW106

SW104

SW102

SW100

SW107

SW105

SW103

SW101

P100 P100To Ft Control


Side Key Assembly P100 Side Key Assembly P100 Voltage and Diode CheckVoltage and Diode Check P100 Resistance Measurements with Key pressed.

CH (Up)CH (Dn)

Volume (+)Volume (-)

KEY

10K Ohms4.8K Ohms1.8K Ohms270.5 Ohms

Pin 3 measured from Gnd

10K Ohms4.8K Ohms1.8K Ohms270.5 Ohms


EnterMenuInput

Power

KEY

P100 Voltage Measurements with Key pressed.

CH (Up)CH (Dn)

Volume (+)Volume (-)

KEY

2.24V1.65V

0.906V0.179V


2.24V1.65V

0.906V0.179V


EnterMenuInput

Power

KEY

P100 Connector “Side Key" to “IR/Intelligent Sensor Board“ P2

GndKey2GndKey1

Label

GndOpenGnd

Open

Diode Check

GndGnd43.3V3.3V3GndGnd23.3V3.3V1

Run STBYPin

P100


INVISIBLE SPEAKER SECTIONINVISIBLE SPEAKER SECTION

The 42LH90 contains the Invisible Speaker system.The Full Range Speakers point downward, so there is no front viewable speaker grill or air ports.

Tweeterp/n EAB58536001

Full Rangep/n EAB58534501

Tweeter(High Frequencies)

Main Speaker(Full Range Frequencies)


Invisible Speaker System Overview (Tweeters)Invisible Speaker System Overview (Tweeters)

Invisible Speaker has a adhesive surface which adheres to front bezel.

Invisible Speaker Tweetershown separately. The Front (down)

has an adhesive surface which adheres to front bezel. Note, there is

no diaphragm, only voice coil.Outlined

Circle

SpeakerAttachment

post

Cabinet works as a diaphragm.

Elimination of the conventional

speaker.

The front bezel is shown below. Note: the outlined circle is the location for the front adhesive pad on the Invisible Speaker. This prevent the coil from

bouncing off the plastic causing vibrations.

WARNING: Removing the Tweeter will destroy the speaker as shown above. The diaphragm/spider is glued to the

front bezel. When removing, it will tear.

Tweeter p/n EAB58536001


Invisible Speaker System OverviewInvisible Speaker System Overview

Invisible SpeakerShown separately. Front (to left) has an adhesive surface which adheres to front bezel. Note, there is

no Cone (Diaphragm), only voice coil.

Spider

Dust Cap with

adhesive

Voice CoilInside

Magnet

Frequency Pass Capacitor

Mount

Mount

Speaker Wires

Speaker Terminals

Tweeter p/n EAB58536001


INTERCONNECT DIAGRAM (11 X 17 FOLDOUT) SECTIONINTERCONNECT DIAGRAM (11 X 17 FOLDOUT) SECTION

This section shows the 11X17 foldout thatThis section shows the 11X17 foldout that’’s available in the Paper s available in the Paper and Adobe version of the Training Manual.and Adobe version of the Training Manual.

The Adobe version of this Training Manual allows the viewer to The Adobe version of this Training Manual allows the viewer to zoom in and out making reading of the small text easier.zoom in and out making reading of the small text easier.This Power Point shows a graphical representation of the 11 X 17This Power Point shows a graphical representation of the 11 X 17foldout page so clarity is limited.foldout page so clarity is limited.

P201

SK100

SK101

F100

SMPSSwitch Mode Power Supply

Hot Gnd

Hot Gnd

P203

LN

F101

AC IN

3.15A250V

5A250V

BD101

Bridge Rectifier

Q102

Q101

Q601

Q602

D601

D211

D213

D215

T101

L601

D201

T501

IC501

IC502

IC503

IC102

159.9V in Stand-By190 in Run

42LH90 INTERCONNECT DIAGRAM

SMPS TEST 1: To Force Power Supply On.Disconnect P700 on Main PWB.Jump pin 7,8,9 or 10 (5V) to pin 2 using a 100Ω resistor. (Test Voltage Outputs 12V, and 24V).

SMPS TEST 2: Jump pin 2 to pin 20 (INV-ON).(Backlights and all voltages should turn on).

P1200 "MAIN” to P101 "Front IR / LED

Main Power SW

Side (Key) C

ontrols P101

Front PWB AssemblyIR Receiver

Intelligent Sensor

P100P102

P102 "Front IR / LED PWB to P100 KeysTuner

2PDIM Pin 24 can vary according to type of signal being processed and the OSD Backlight setting. 0.6V 0% to 3.3V 100%. Output from the IC100 Video Processor.

1ADIM Pin 21 Fixed and not used

SpeakersJ1

P100GndKey2GndKey1

Label

GndOpenGndOpen

Diode Check

GndGnd43.2V3.2V3GndGnd23.2V3.2V1

Run STBYPin

Open3.2V0V12Open3.2V3.3V_ST11GndGndGndGnd10Open3.5V3.5VIR9

Open0V0VWarm ST8GndGndGndGnd7

5.1V5.1V5V ST63.2V3.2VKey253.2V3.2VKey14

GndGndGndGnd33.3VSDA2

Open3.3V0.57VSCL1Diode CheckRun STBYLabelPin

POWER On/Off3.2V

STBYLabel

0.57V

OpenOpenOpen

Open

TO TFT MODULE

125V / 3A

CN5 CN4

TO TFT MODULE

UC1

FL1

D8

L1

F1 (12V)

TO TFT MODULE

T-CON(TFT Driver)

Gnd Protect

FL2Gnd Protect

CN1

U11

D7

L2 D9

D10

Q1

U12

U10

Pin 2Pin 4

Pin 56,57,58

Pin 53,54

U5

1) 0V2) 1.19V3) 3.3V

B2.78V E

3.3V

C3.3V

16V

20.5V 14.25

V

-2.4V

12

32

R701R702

R70

4R

705

R70

6

16V26V

27V

26V16V -4.9V3.3VPin 59

Pin 57Pin 3,4,5

Pin 7,826V16V-4.9V3.3V

C74

4R

721

( 12V )

U5

Gnd -4.9V

U5 B+ ( 12V )

3.3VVCC

16V

3.3V

CN2

VDD

1) Gnd2) Gnd3) Gnd4) Gnd

8) 3.34V7) 3.09V6) 3.34V5) 3.34V

FLA

SH

P3500

IC3502Tru-

Motion/Dimming

P3502

IC3502 Operates at

high temperature

P3501

P700

X350025Mhz

IC3503

IC3504

IC3500

Q706

ECB

Q702

IC706

ECB

Q701

L718

L710

IC701

L726

IC705

IC704

IC2

SW3500Not Used

IC801

IC901

IC900

X80012Mhz

IC1

X10012Mhz


Mstar

IC707

L712

IC708

IC1000IC1001

IC101

SW100

ECB

Q100

IC105

IC502

IC600

L607

L606

P1200

EC B Q106

IC1002

Q1200

ECB

IC1203

TU1001 TunerTDVW-H103F

(1)

Analog Video (19)

Tuner 5V_TU (4)

Data (8)Clock (9)

Dig DIF+ (12)Dig DIF- (13)SIF (16)

X100525Mhz

P101N/A

IC1004

D1000

12V LVDSPins 1~4

P600

IC3505

C A1

A2D1223

IC1200

IC1201

D500

C

A1 A2

Q1001

E CB

Q1000

IC1003

IC703

ECB

CA1

A2

ECB

2 31

Q105IC103

IC702IC104

IC102

IC800

IC1202

IC501

Q703

EC B

Q704

EC B

Q705

EC B

IC10723

1

D102

Q600E CB

42LH90MAIN BOARD

Grayed Out Components are on the Back

D1000

D208

D207Q212 Q211

L204

L203IC201

680u

F35

V

C203Q210

Q209

680uF35V

C212

D202

D203Q205 Q204

Q10

Q9

L202

L201

C27

D8

D7Q12 Q11

L4

L3

+

-

+ -

680u

F35

V

C3

+ -

Q202

Q203

680uF35V

-

+

C12

D2

D3

Q5 Q4

L2

L1

680uF35V

-

+

Q2

Q3

F112A/65V

ZD3

CN1

F22A/125V

L5

-

+

680uF35V

C40

CN3

CN4

IC1 IC3

21

322

1

32

IC4 IC15

Q35

Q36

Q37

Q34

Q33

Q32IC8IC9Q31

Q30

Q29

Q28

Q27

IC7IC10

Q38

Q39

Q40

Q41

Q42

IC6IC13

Q43

Q44

Q45

Q46

Q26

Q25

Q24Q23

ZD303ZD304

Q22

IC5

IC14

CN307

CN306

n/c

Q21

Q20

Q19CN305

n/c

Q47

Q48

Q49

Q50

IC301Processor

Y301 (12Mhz)213

221 3

2IC303

IC302

680uF35V

C227 +

-

12345

1.25Vp/p1.76Vp/p

D302

To Backlights

To B

ackl

ight

s

24V CN1 "INVERTER" TO P203 "SMPS"

For Voltages see CN1 Table

P203 "SMPS" TO CN1 "INVERTER"

1Ext_VBR_B same as (P-DIM)

OPENOPEN

OPENGNDGNDGNDGNDGND0.74V

Pin Label14 AGP13 Ext_VBR_B12 ON/OFF11 NC10 GND9 GND8 GND7 GND6 GND

1-5 VIN

OPEN

Diode Check

Pin Label STBY Run Diode Check

14 AGP 0V 0V OPEN

13 1Ext_VBR_B 0V 0.33V-3.2V OPEN

12 ON/OFF 0V 4.65V 1.6V

11 NC 0.47V 1.66V OPEN

10 GND GND GND GND

9 GND GND GND GND

8 GND GND GND GND

7 GND GND GND GND

6 GND GND GND GND

1-5 VIN 0V 24.0V 2.9V

LED Board

M1

M2

M3

M4

M1-M4 (27.5V)

24V

D302 blinks 1Hz OK

For Main board component Voltages see PG 3 of Interconnect Diagram

INVERTER Board

Q19 through Q50Note: Each output driver (switch) has a TP to the left and right

representing a “V” which indicates a Block of LEDs.V34 represents Pin 23 of CN4V33 represents Pin 24 of CN4

Grounding these points when the 27.6V supplies are working will cause the entire Block of Backlight LEDs to turn on.

(100mA to light one block)

P700 "Main" to P201 “SMPS"

For Voltages see P201

1.3V

Open

2.6V

Diode Check

2.9V

2.2V

1.1VGnd

Open

Open

1

19

21

23

2

20

22

24

3,4,5,67,8,9,1011,1213,14

15,1617,18

Gnd

Gnd

Open

Open

Open

12V LVDS Pins 1~4

12V LVDS Pins 48~51(Pin 1)

3.54Vp/p

(Pin 4)3.48Vp/p

(Pin 6)3.46Vp/p

P/N EAT60665101

P201 “SMPS" to P700 "Main"

ncncnc1

Gnd

nc

Diode Check

GndGndGnd

Open5.15V5.15V5V

GndGndGndGnd

0.98V12V0V12V

0.74V24V0V24V

ncncncnc19

Open1.66V0V1 A.DIM21

ncncnc23

Run STBYLabelPin

1.6V4.98V0VPWR-On2

Open4.65V0VINV.ON20

Open0V0VErr Out22

Open3.2V0V2PDIM24

7,8,9,10

11,12

13,14GndGndGndGnd15,16

17,18

nc

3,4,5,6



INVERTER CN3-CN4 INFO.CN4

27.5V Line on CN4Pins 1-2 (Out_M3)Pins 13-14 (Out_M3)Pins 16-17 (Out_M3)Pins 26-29 (Out_M3)Pins 31-32 (Out_M1)Pins 43-44 (Out_M1)Pins 46-47 (Out_M1)Pins 58-59 (Out_M1)

42LH90 MAIN (FRONT SIDE) SIMICONDUCTORS

IC101 Serial Flash IC704 +3.3V_FE IC707 +1.8V_MEMC IC1001 +3.3V_PVSB IC3500 +3.3V_Dimming Q100 W/P IC101 Q706 +5V/12VLVDSPin Memory Pin Regulator Pin Regulator Pin +3.3V_FE Pin Regulator Pin Pin Switch[1] 0.05V [1] 0.8V [1] 0.8V [1] 4.94V [1] Gnd B 0V [1] 5.1V[2] 3.2V [2] Gnd [2] Gnd [2] 4.94V [2] 3.3V C 2.5V [2] 0.29V[3] 2.5V [3] 5V [3] 4.92V [3] Gnd [3] 5V E Gnd [3] 11.9V[4] Gnd [4] 7.5V [4] 6.5V [4] 3.4V [4] 5.99V[5] 0V [5] 5V [5] 4.8V [5] 1.25V IC3503 +1.8V Reg Q106 S5/S6 Reset [5] 11.98V[6] 0V [6] 3.3V [6] 1.8V Pin Dimming Pin Mstar [6] 11.98V[7] 3.3V [7] 3.3V [7] 1.8V IC1002 +5V_TU [1] 0.58 B 0V [7] 5.06V

[8] 3.3V [8] 2.1V [8] 4.8V Pin Tuner [2] 1.8V C 3.28V [8] 5.06V[1] 8.92V [3] 3.19V E 0V

IC105 HDCP IC705 +1.26V_VDDC IC708 +1.26V_MEMC [2] 1.88V Q1200 IR RS232Pin EEPROM Pin Regulator Pin Regulator [3] 5.04V IC3504 Dimming Q702 INV_ON Pin Buffer[1] Gnd [1] 0.8V [1] Gnd [4] 0V Pin EEPROM Pin Inverter B 0.634V[2] Gnd [2] Gnd [2] 0.8V [5] Gnd [1] Gnd B 0.05V C 0.97V[3] 3.29V [3] 5V [3] 1.26V [2] Gnd C 4.66V E Gnd[4] Gnd [4] 6V [4] 1.26V IC1203 SPIF Optical [3] Gnd E Gnd[5] 3.3V [5] 3.2V [5] 1.8V Pin Audio [4] Gnd D1000 Speed Up Reset[6] 3.3V [6] 1.2V [6] 5V [1] 1.58V [5] 3.3V Pin IC1004[7] 0V [7] 1.26V [7] 1.26V [2] 3.2V [6] 3.3V C 3.4V

[8] 3.3V [8] 5V [8] 5V [3] Gnd [7] 0V A 3.38V[4] 1.61V [8] 3.3V

IC701 +1.8V_DDR IC706 5V_EXT IC1000 +1.26V_PVSB [5] 3.21VPin Regulator Pin Memory Pin Regulator[1] 0V [1] 0.8V [1] 0V[2] 3.2V [2] Gnd [2] 3.39V[3] 3.2V [3] 12V [3] 3.4V[4] n/c [4] 9.6V [4] 0V[5] n/c [5] 5V [5] 0V[6] 1.8V [6] 4.97V [6] 1.21V[7] 0.8V [7] 4.97V [7] 0.8V

[8] Gnd [8] 1.9V [8] Gnd

42LH90 MAIN (BACK SIDE) SIMICONDUCTORS

IC103 Reset Gen IC703 +3.3V_ST IC1200 RGB IC1202 USB +5V Q703 5V Switch Q1001 Tuner VideoPin Mstar IC100 Pin Regulator Pin EEPROM Pin Switch Pin Control Pin Buffer[1] Gnd [1] 0V [1] Gnd [1] 4.95V B 0.6V B 3.09V[2] 0V [2] 1.8V [2] Gnd [2] Gnd C 0.03V C 0V[3] 3.3V [3] 3.21V [3] Gnd [3] 3.21V E Gnd E 3.72V

[4] Gnd [4] 4.95VIC104 RGB (PC) [5] 4.82V [5] 0V Q704 1st 12V LVDS D102 Audio Mute

Pin EEPROM IC800 SPI Flash [6] 4.82V [6] 4.95V Pin Switch Control Pin Routing[1] Gnd Pin [7] 4.82V B 0.05V A1 0.047V[2] Gnd [1] 0.12V [8] 4.82V IC3505 Reset Gen C 0.65V C 0.089V[3] Gnd [2] 1.13V Pin for IC3502 E Gnd A2 0V[4] Gnd [3] 3.26V IC1201 RS232 [1] 3.3V[5] 3.22V [4] Gnd Pin Rx/Tx [2] Gnd Q705 2nd 12V LVDS D500 Shunt for[6] 3.22V [5] 0.06V [1] 3.3V [3] 3.22V Pin Switch Control Pin IC501[7] 0V [6] 1.2V [2] 5.56V B 0.65V A1 3.25V[8] 3.22V [7] 3.27V [3] 0.02V Q105 PWR On Delay C 0.0V C 3.12V

[8] 3.27V [4] 0.03V Pin Q2405 E Gnd A2 0VIC107 Power Det [5] 5.46V B 0V

Pin Gen IC1003 9V Reg [6] 5.5V C 1.95V Q1000 Tuner SIF D1223 5V Routing[1] Gnd Pin to IC1002 [7] 5.5V E Gnd Pin Buffer Pin for IC1200[2] 3.9V [1] 12V [8] 0V B 2.4V A1 0V[3] 3.28V [2] Gnd [9] 3.29V Q600 Audio Mute C 0V C 4.82V

[3] 8.9V [10] 3.24V Pin Switch E 3.85V A2 5.11VIC702 +3.3V_ST For Tuner Voltage 5V [11] 0.02V B 0.08V

+3.3V_AVDD_MPLL [12] 3.29V C 3.26VPin Regulator [13] 0V E Gnd[1] Gnd [14] 5.5V[2] 3.29V [15] Gnd[3] 5.11V [16] 3.29V

42LH90 LVDS P3500 WAVEFORMS

42LH90 P3500 LVDS CABLE WAVEFORMS:Waveforms taken using SMTP Color Bar input.All readings give the Scale 10mV and Time Base related to scope settings. Top waveform in each image gives a slower rate, 2us per division. Outlined area is shown in the bottom waveform at 500ns per division time base.

Pin 11 Pin 12 Pin 16

Pin 24

Pin 35

Pin 38Pin 37

Pin 30

Pin 23

Pin 20

Pin 13 Pin 14

Pin 17 Pin 21

Pin 27 Pin 28

Pin 36Pin 32

Pin 39 Pin 40

Pin 19 Pin 22

Pin 29

Pin 33

42LH90 LVDS P3502 WAVEFORMS

42LH90 P3502 LVDS CABLE WAVEFORMS:Waveforms taken using SMTP Color Bar input.All readings give the Scale 10mV and Time Base related to scope settings. Top waveform in each image gives a slower rate, 2us per division. Outlined area is shown in the bottom waveform at 500ns per division time base.

Pin 3

Pin 12

Pin 15

Pin 22

Pin 29 Pin 30

Pin 27

Pin 16

Pin 8Pin 4 Pin 5 Pin 6

Pin 11Pin 9 Pin 13 Pin 14

Pin 19 Pin 20 Pin 21

Pin 28Pin 24 Pin 25

Pin 31 Pin 32

42LH9042LH90

This concludes the 42LH90 training

session.

Direct View LCDDirect View LCD

Date post:	22-Mar-2018
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