Microtech © 1998-2002 J. Carlton Gallawa All Rights Reserved Worldwide Last updated 1/2002

This page includes case histories of the brands: Sunbeam to Whirlpool Page 3

Instructions On How To Use These Repair Histories For Troubleshooting And Repairing Microwave Ovens

1. After reading the safety precautions, find the brand and model number, or the number closest to the model you are repairing (you may want to use your browser's find feature).
2. Find the symptom(s) that most closely match the symptom(s) being displayed by the oven you are repairing.
3. Follow the specific troubleshooting and/or repair instructions to complete the repair. Click on highlighted text for a detailed explanation of that procedure.
4. Since this database is constantly being updated and appended, if you don't find what your looking for, try again at a later time.
5. Click here    if you would like to be notified by e-mail when this page is updated.

We hope that you find the information here helpful...

Please Note:

• The manufacturers' part numbers and prices listed here are subject to change without notice.
• The individual model numbers are not necessarily arranged in numerical order

We hope that you find the information here helpful.. .

  Important Safety Information

Repairing a microwave oven is a dangerous task. For your personal safety, please do not proceed unless you fully understand and are prepared to follow carefully these appropriate safety precautions ..

Disclaimer: The author assumes no liability for any incidental, consequential or other liability from the use of this information. All risks and damages, incidental or otherwise, arising from the use or misuse of the information contained herein are entirely the responsibility of the user.  Although careful precaution has been taken in the preparation of this material, we assume no responsibility for omissions or errors.

© 1996-2002 J. Carlton Gallawa
All Rights Reserved Worldwide
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MICROWAVE OVEN REPAIR CASE HISTORY DATABASE (CONT'D)

SUNBEAM

Model: 24011

Symptom: Microwave mode does not work-perhaps accompanied by an electrical burning odor.

Problem: Weakened fuse clips on fuse receptacle causing fuse to melt due to resistive heat. Usually indicated by a bead of solder leaching out from either endcap and/or evidence of overheating (burned spot) at the terminal connection. Also several other connections have burned loose, as indicated by discolored, melted connectors and insulators. In addition, the high-voltage transformer is shorted.

Test: High-Voltage Transformer Test

Solution: Replace fuse ($1.00) and fuse receptacle ($3.00). Also, inspect wiring for burned connections. Repair or replace as necessary. Replace high voltage transformer-price:about $50.00

TAPPAN

Model: 56-2146/02, 56-2533, 56-3354/04, 56-4274, 56-9439

Symptom: Dead. May have gone dead either immediately after starting cook, or sometime during cook.

Problem: Weakened fuse clips on fuse receptacle causing fuse to melt due to resistive heat. Usually indicated by a bead of solder leaching out from either endcap and/or evidence of overheating (burned spot) at the terminal connection

Solution: This model is designed with the fuse holder as part of the power cord. Thus, the entire assembly must be replaced. Otherwise, clean and tighten the fuse clips. Then, solder the new 20 amp fuse into the receptacle to insure a durable connection.

TAPPAN

Model: 56-3664-10/02116

Symptom: Seems to operate, but it does not heat.

Problem: Defective interlock switch

Test: Interlock Switch Test

Solution: Replace defective interlock switch. Generic switches are available at appliance parts suppliers. Contact current rating must meet or exceed that of the original, and terminal configuration must be appropriate.

TAPPAN

Model: 56-4799/03

Symptom: Plugged into wrong voltage. Now dead.

Problem: Varistor on low voltage transformer shorted out and blew the fuse.

Solution: . Replace varistor. Install new 20 amp fuse.

TAPPAN

Model: 56-4901-10

Symptom: Weak heat

Problem: The magnetron filament connectors have loosened and, due to resistive heat, the terminal connections have deteriorated and burned off of the terminals

Solution: Repair defective terminals as follows:Either (1) Cut away burned wire, clean the magnetron terminals, and replace the slip-on connectors, or (2) Cut away burned wire and connector(s). Clean terminals to prepare for soldering. Solder filament leads directly to magnetron terminals. Be careful not to apply soldering heat any longer than necessary. Note:If the magnetron terminals are burned too severely, the magnetron may need to be replaced.

TAPPAN

Model: 56-9532/02

Symptom: Dead

Problem: Broken connection at pin #3 on main harness connector.

Solution: Repair cracked solder connection on printed circuit board.

TAPPAN

Model: 56-4878-10/01

Symptom: Control panel dead.

Problem: Low voltage transformer on control board has open primary winding.

Solution A: Tappan (Frigidaire) would have you purchase the entire control panel assembly (Touch Panel Complete), the cost of which is beyond what's reasonable or practical.

Solution B: Seek out a cooperative local repair shop who may have a supply of used circuit boards. If a similar low-voltage transformer can be located, replace the defective one. If a used board cannot be located, send us E-Mail

THERMADOR

Model: MC17

Symptom: No heat.

Problem: Shorted magnetron tube.

Test: Magnetron Test

Solution: Replace magnetron. Thermador part # 14-29-102

THERMADOR

Model: MC17, MC19

Symptom: Fan making noise.

Problem: Fan mounting dampers deteriorated, allowing fan assembly to drop down so that fan blade scrapes and binds.

Solution: Replace dampers, part # 19-09-747. Reinstall blower assembly.

TOSHIBA

Model: ER-855BT-4

Symptom: Weak heat-won't pop popcorn

Problem: Weak magnetron tube

Test: Power Output Test

Test: Magnetron Test

Solution: Replace magnetron. Most appliance parts suppliers handle a line of reliable replacement magnetrons priced at about $45.00 - $60.00

TOSHIBA

Model: ERS-6631B

Symptom: Hear a clicking sound when pads are pressed, but it but won't start

Problem: Defective membrane touch panel

Solution: Replace touch panel

WESTINGHOUSE

Model: KM485LXM1KLJ2660

Symptom: Gradually decreasing output power

Problem: The magnetron filament connectors have loosened and, due to resistive heat, the terminal connections have deteriorated and burned off of the terminals

Solution: Repair defective terminals as follows:Either (1) Cut away burned wire, clean the magnetron terminals, and replace the slip-on connectors, or (2) Cut away burned wire and connector(s). Clean terminals to prepare for soldering. Solder filament leads directly to magnetron terminals. Be careful not to apply soldering heat any longer than necessary. Note:If the magnetron terminals are burned too severely, the magnetron may need to be replaced.

WHIRLPOOL

Model: MH6700XV-1

Symptom: Shortly after starting to cook, the oven tripped the circuit breaker. Now it is dead.

Problem: Shorted high voltage transformer

Test: High-Voltage Transformer Test

Solution: Replace high voltage transformer, part # 815129, price $104.00. Also replace line fuse.

WHIRLPOOL

Model: MW1500XS-0

Symptom: Some number on the touch panel will not respond.

Problem: Faulty touch panel

Solution: Replace touch panel (key unit). Part # ????. Price ????

WHIRLPOOL

Model: MW3500XS-0

Symptom: Control panel just beeps at random.

Problem: Defective key pad (touch panel)

Solution: Replace key pad. Part # 4158199. Price:about $50.00

WHIRLPOOL

Model: MW8500XR, MW8520XP, MW8550XL, MW8650XR, MW8650XS, MW8750XP

Symptom: Weak or uneven heat

Problem: Broken stirrer belt

Solution: Replace stirrer belt. Part # 311958 Price:$5.00

WHIRLPOOL

Model: MW8520XP

Symptom: Clock counts down but nothing else works

Problem: Deteriorated and cracked solder connections on printed circuit board.

Solution: Inspect circuit board, and repair deficient solder joints as necessary.

WHIRLPOOL

Model: MW8600XR

Symptom: (1) Oven starts and counts down, but does nothing else. (2) Also, the front panel frame is falling off

Problem: (1) Cracked and burned solder joints at main harness plug on the printed circuit board. (2)The front panel is mounted by means of screws that thread into plastic standoffs, which are mounted on the control panel frame. In time, these standoffs deteriorate and break off, allowing the panel frame to come loose.

Solution: Clean, reinforce and re-solder the pins where the main wiring harness plug connects into the circuit board. Also, because the cost of a new front panel frame is inexplicably exorbitant, the frame can be secured using a good quality two-sided tape

WHIRLPOOL

Model: MW3500XM

Symptom: Some pads will not respond to programming.

Problem: Defective mylar touch panel.

Solution: Replace touch panel, part # 788039

Parts Suppliers and Manufacturer Contacts You can contact these parts suppliers and microwave oven equipment manufacturers directly for replacement parts, product literature, dealer locations, technical assistance, etc. Please e-mail additions or corrections to: j.gallawa@cox.net Glossary of Electronic and Microwave Oven Related Terms  Let us know what you think, or submit your own repair tip j.gallawa@cox.net

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THE COMPLETE MICROWAVE OVEN SERVICE HANDBOOK 2000 Operation, Maintenance, Troubleshooting and Repair J. Carlton Gallawa