2015 Microwave Training

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PresenterPresentation NotesWelcome to 2015 Microwave update training.

Contents

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Faults Test procedures and tools No power No heat Intermittent heat issues Turntable testing

PresenterPresentation NotesThis presentation will cover; faults, test procedures, no power issues, no heat issues and intermittent heat issues.

Fault Codes

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SE error can be confirmed by first removing power to the unit Then unplug the ribbon connector from the key pad at the board Plug the unit back into power supply and at least wait 60 seconds If the SE fault doesnt return suspect a stuck key or a damaged ribbon connector.

Both the E-83 & TE errors are explained above

PresenterPresentation NotesSE error can be tested by unplugging the ribbon connector from the board (with unit unplugged) If the error doesnt come back while unplugged replace control as per GSPN.Both E- 83 and TE errors are explained in the slide.

GaAs sensor Error codes

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The GaAs (gallium arsenide) Sensor detects both humidity (steam) and hydrocarbons (food odors) during the cooking process. Before doing the sensor test ensure the unit has been plugged in for 5 minutes.

This allows the heater in the sensor to warm up properly.

E-11 Open Sensor E-12 Shorted Sensor For both faults check plug, wiring or board. If error occurs when starting sensor function, replace the board .

PresenterPresentation NotesIt is important that the unit is plugged in for at least 5 minutes to warm heater before testing.To enter the test touch auto defrost and popcorn pads at the SAME time then watch the diagnostic numbers in the display area.The GaAs sensor test will show numbers that indicate normal (pass) or failure (sensor open or shorted).Normal is between 15 to 185, less than 6 indicates a shorted sensor or smart board and 213 or higher indicates sensor failed to open, sensor unplugged, wiring or smart board failure.Only wire leads or terminals black and red (which are for the heater)can be checked with an ohm meter and should read approximately 30 ohms.DO NOT ATTEMPT TO CHECK SENSOR TERMINALS WHITE OR ORANGE AS IT WILL DAMAGE THE SENSOR!!GaAs (gallium arsenide) sensors detect both humidity (steam) and hydrocarbons (food odors) during the cooking process.

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Check if the leakage of microwave is below 5mW/cm2 before returning the oven to customers.

Check your tools Do you have a M/W Survey Meter? Check your Calibration Date? Most meters need yearly certification.

Important to note Microwave Leakage Detector

PresenterPresentation NotesYou must carry a currently calibrated and certified survey meter and record leakage before and after you work on the microwave.It must read less than 5mW/cm2 before returning the unit to the customer.

Test your meters too!

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This is a photo of 2 identical meters with 2 very different voltage readings. They were also off on resistance and DC voltages. This is why it is important to test your meters on a regular schedule. You can not get accurate results if your tools dont work properly.

PresenterPresentation NotesTest your volt/ohm meters with a known 120volt AC source and a fresh 9 volt battery before testing products.Failure to have accurate meters may result in misdiagnosed parts and products.

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Make sure 120 volts is supplied at the outlet. Be sure the outlet is polarized and grounded properly.

It should on be a dedicated 20 amp breaker. If power cuts out during use of the unit, check if the circuit breaker has allowable current to meet the operating criteria.

Troubleshooting - No Power

PresenterPresentation NotesMake sure to start with the basics and test for 120 volts at the products outlet.If power cuts out during use of the unit then check if the circuit breaker is on a dedicated 20 AMP breaker. Also make sure the product is drawing the proper amperage or wattage during use. This will help you determine if the unit or the customers house wiring or breaker is at fault.

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NEVER TRY TO TEST COMPONENTS BEFORE DISCHARGING CAPACITOR

FIRST STEP ALWAYS, ALWAYS DISCHARGE THE CAPACITOR ANYTIME YOU WORK INSIDE THE CABINET OR WRAPPER AREA

VERY IMPORTANT!!

SAFETY FIRST

PresenterPresentation NotesAfter unplugging the unit and before working on the High Voltage side of the Microwave make sure you discharge the Capacitor. Use either 2 insulated screwdrivers to short out the capacitor OR a well insulated pair of needle nose pliers.

You might hear a loud pop if the capacitor is charged. It is a good idea to advise the customer about the possible sound before doing this.

Discharging the capacitor is very important to your safety and should be done every time the outer cover has been removed.

NEVER TRY TO TEST COMPONENTS BEFORE DISCHARGING THE CAPACITOR!!!

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Troubleshooting - No Power

We use both single and double fused filter boards

Power comes in first through the bottom TCO to the filter board on the right side, it then passes through the 20 amp board fuse and leaves on the left side towards the primary door switch, cavity and magnetron TCOs and the control board. By testing at a few key spots you can test multiple parts, speed up your diagnoses and still be accurate in finding any problems in the low side of the system.

PresenterPresentation Notes The main Fuse has to do with Power , the HVT Fuse is for heating.. If the noise filter board only has one fuse, it will be the main fuse. When the noise filter has two fuses the bottom one is the main fuse.

Power comes in first through the bottom TCO to the filter board on the right side, It then passes through the 20 amp board fuse and leaves on the left side towards the primary door switch, cavity and magnetron TCOs and the control board.

By testing at a few key spots you can test multiple parts, speed up your diagnoses and still be accurate in finding any problems in the low side of the system.

First do a continuity test

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With the unit unplugged from the power supply and the capacitor discharged; Connect a multi-meter at the positive (+) end of the power cord and at black wire at transformer connector (remove the connector) with door closed Your meter should show a complete circuit (continuity). This will test bottom TCO, fuse, magnetron TCO, cavity TCO and primary door switch. To test the primary door switch; door closed= continuity door open =open circuit Now connect to both wires at the transformer connector to test the Monitor switch; door open = continuity, door closed =open circuit. Note: monitor switch works opposite of the other 2 switches Finally remove the door sense connector on the control board and test for continuity; door closed = continuity, door open = open circuit If any part of these tests fail then work backwards component by component.

PresenterPresentation NotesFirst do continuity tests by doing the following procedures;

With the unit unplugged from the power supply and the capacitor discharged;Connect a multi-meter at the positive (+) end of power cord and at the black wire at the transformer connector (remove the connector) with door closed, your meter should show a complete circuit (continuity). This will test bottom TCO, fuse, magnetron TCO, cavity TCO and primary door switch.To test the primary door switch; door closed= continuity door open =open circuit

Now connect to both wires at the transformer connector to test the Monitor switch; door open = continuity, door closed =open circuit. Note: monitor switch works opposite of the other 2 switches

Finally remove the door sense connector on the control board and test for continuity; These are usually small orange wires but always check the wiring diagram to confirm. door closed = continuity, door open = open circuit

If any part of these tests fail then work backwards component by component.

Door Switches

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PRIMARY INTERLOCK SWITCH

MONITOR SWITCH

DOOR SENSING SWITCH sometimes called

SECONDARY SWITCH

PresenterPresentation NotesThe above slide shows the many different faults and symptoms of the three door switches.Please refer to the slide for the most accurate information about them.

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Blue Connector Power In

Low side CAUTION; LIVE VOLTAGE TEST!!!!

To test 120vac supply through to the control board insert meter leads between both wires at the blue connector. You should get 120vac. if everything is working to the board. Now power the unit on and check for 120vac at the primary leads at the transformer, no 120vac = no board output.

PresenterPresentation NotesNext we will do a live voltage test to make sure the smart board receives its needed voltage to operate properly. THIS IS A LIVE TEST SO USE EXTREME CAUTION!!!!First plug the unit in to the house power supply that you have already verified as proper (polarity, ground and 120vac).To test the 120vac supply through the TCOs, fuse and door switches to the control board insert the meter leads between both wires at the blue connector. You should get 120vac. if everything is working to the board.

Now power the unit on and check for 120vac at the primary leads at the transformer, no 120vac = no board output.

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TCO Intermittent Power

Intermittent power issues are normally caused by a TCO tripping off and on.

The bottom TCO, cavity TCO and magnetron TCOs are all resettable after reaching their low reset temperature.

The Base and Hood TCO are normally at the bottom of the unit. One way to tell the difference between them is by the colors of the wires, red wires will tell you its a Hood TCO. To help remember the difference just remember the story Little Red Riding Hood red wires = hood TCO

HOOD BASE

PresenterPresentation NotesIntermittent power issues are normally caused by a TCO tripping on and off or a wire that is not plugged on properly (like just connected by the insulator).

The bottom TCO , Cavity TCO and Magnetron TCO are resettable after reaching the low reset temperature.

The reset temperature should be printed on the back of the TCO.

One way to tell the difference between them and the hood TCO is by the colors of the wires, red wires will tell you its a Hood TCO.

To help remember the difference just remember the story Little Red Riding Hood red wires = hood TCO

THE HIGH SIDE

PresenterPresentation NotesBasically the high side is made up of four components that in a working relationship with each other perform the capability collectively to enable the heating process.

The components are the diode, the capacitor, the transformer and the magnetron.

As a safety note the high side is called the high side for a reason. Voltage is stepped up by the transformer and through the circuitry it outputs often over 4000 volts. The Capacitor is an electrical storage device. It will store a charge and as such if you mishandle it, it can discharge its energy through you so please take note of the next slide.

15 POP!!!

NEVER TRY TO TEST ANY COMPONENTS BEFORE DISCHARGING THE CAPACITOR.

No Heat ALWAYS discharge the capacitor before working inside the unit !!!

There may be a loud POP sound so make the customer aware before discharging

PresenterPresentation NotesAfter unplugging the unit and before working on the High Voltage side of the Microwave make sure you discharge the capacitor.

Use two screw drivers or an insulated needle nose plier to short out the capacitor.You might hear a loud pop if the capacitor is charged so make the customer aware of this first.

Discharging the capacitor is very important to your safety and should be done every time the outer cover has been removed.

NEVER TRY TO TEST COMPONENTS BEFORE DISCHARGING THE CAPACITOR !!!!

Not Heating

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If you have a filter board with 2 fuses check the top fuse, connectors and wiring. Make sure there is 120vac in and out of the filter board through the fuse.

Next check for 120vac into the primary at the transformer. If you do not have 120vac at the transformer then the problem is in the low voltage section. This procedure will keep you focused on the proper section; either low voltage or high voltage.

120 vac IN 120vac

out

PresenterPresentation NotesFor a no heat issue;If you have a filter board with 2 fuses check the top fuse, connectors and wiring.Make sure there is 120vac in and out of the filter board through the fuse.

Next check for 120vac into the primary at the transformer. If you do not have 120vac at the transformer then the problem is in the low voltage section.

This procedure will keep you focused on the proper section; either the low voltage or high voltage sides.

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Check the 3 terminals on transformer for continuity. If there is continuity between ground and any terminal then replace the transformer.

No Heat Continuity Check of Transformer

On transformers with just 2 wires check resistance across them and then from each terminal to ground as above.

PresenterPresentation NotesNo Heat Continuity Check of Transformer

Check for continuity between the 3 terminals of the transformer.

Check for no continuity between ground and all 3 terminals. If you find continuity during this check there is something shorted out so replace the transformer.

On transformers with just 2 wires check resistance across them and then from each terminal to ground as above.

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Continuity Check Beep!!!

NO Beep!!!

Check Magnetron for continuity between terminals and between each terminal and ground, if continuity to ground or it is noisy replace the magnetron.

No Heat Continuity Check of Magnetron

PresenterPresentation NotesCheck the Magnetron by doing a Continuity Check between the two terminals of the magnetron. This test will indicate a good working Magnetron.There shouldnt be any noise or when checking each terminal to ground.

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No Heat Checking Diode with 9V

PresenterPresentation Notes

The following test should be done to test a diode 1. Isolate the diode from the circuit by disconnecting its leads. 2. With the ohm-meter set at the highest resistance scale, measure across the diode terminals. 3. Reverse the meter leads and read the resistance. A meter with 9V or higher voltage batteries should be used to check the front- to back resistance of the diode. Otherwise, an infinite resistance may be read in both directions. Or you can put 9v battery in series with the meter. 4. The resistance of a normal diode will be infinite in one direction and several hundred K in the other direction.

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A loose screw could cause arcing or no heating.

No Heat Diode Connection

PresenterPresentation NotesA loose mounting screw could cause arcing and no heating, make sure the screw is tight.If it has overheated or is arced replace the screw or clean it and the diode lead with a wire brush to insure good contact.

Make sure the Capacitor is discharged before testing!!!! 1. Check continuity of the capacitor with the meter set at the highest resistance scale. 2. Once a capacitor is charged it shows continuity for a short time then indicates 9M. 3. A shorted capacitor will show continuous continuity. 4. An open capacitor will show 9M constantly. 5. Resistance between each terminal and chassis should read infinite.

Capacitor Testing

PresenterPresentation NotesHigh Voltage Capacitor testing

1. Check continuity of the capacitor with the meter set at the highest resistance scale. 2. Once the capacitor is charged, a normal capacitor shows continuity for a short time, and then indicates 9M.3. A shorted capacitor will show continuous continuity.4. An open capacitor will show 9M constantly.5. Resistance between each terminal and chassis should read infinite.

Turntable Troubleshooting

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The turntable receives 24vac during cooking cycle. A continuity test between terminals at the motor should read about 150 ohms. It is accessible and removable from under the unit.

PresenterPresentation NotesThe turntable receives 24vac during the cooking cycle to rotate the food on the turntable.A continuity test between terminals at the motor should read about 150 ohms.It is accessible and removable from under the unit.

Thank You!

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PresenterPresentation NotesThank you, this concludes our 2015 microwave update training. Make sure you take the 2015 Microwave exam

Slide Number 1Contents Fault Codes GaAs sensor Error codesSlide Number 5 Test your meters too!Slide Number 7Slide Number 8Slide Number 9First do a continuity testDoor SwitchesSlide Number 12Slide Number 13Slide Number 14Slide Number 15Not HeatingSlide Number 17Slide Number 18Slide Number 19Slide Number 20Capacitor TestingTurntable TroubleshootingThank You!