• ** REMEMBER! **The microwave can still shock you even unplugged!!

    ALWAYS discharge the high-voltage capacitor first if you even think your hands will come close to any HIGH VOLTAGE components.

    Jeff mentions this: Anything in the high voltage ( magnetron, capacitor, diode, wires to and from ):
    ...Use a metal ( not the shiny chrome type ) screw driver with a insulated handle to short across ( touch both at the same time ) the terminals of the high voltage capacitor to discharge it.

    From Jeff's site: http://www.applianceaid.com/component-testing.php

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Whirlpool Gold GMC275PRB01, Serial #XT1111954, DOM 03/2006, Micro/Oven wall unit, micro not heating


Jan 22, 2021
Model Number
More than 10 years
Hello Everyone/Anyone,
I have a Whirlpool Gold GMC275PRB01 Microwave/Oven wall unit, made in March of 2006. One day the microwave quit heating. Runs and operates like normal, just doesn't heat. I did some research, and decided to start by replacing the High Voltage Diode. Bought one online for like 10 bucks, replaced it, reassembled the unit and slid it back in the wall (very aggravating). Turned it on and it worked! The microwave heated like normal. So I patted myself on the back and boasted to my wife on how much money we saved. Well about two days later, the microwave quit working, quit heating again (easy come, easy go).

So I did some more research, this time I bought a new magnetron online for about 20 bucks, replaced it, reassembled the unit and slid it back into the wall, again (very aggravating). Turned it on and it worked again! The microwave heated like normal. I decided to wait a while to pat myself on the back and boast to my wife, which I was glad I waited, because after two days the microwave quit heating again (easy come easy go, again). I did a little more research and decided to replace the capacitor. So i bought one online for like 20 bucks, replaced it, reassembled the unit and slid it back into the wall, once again (very aggravating).

Well, whoever is reading this can guess the next two sentences I am going to type. No surprise, the microwave heated again like normal, only to quit heating after about 3 days and a half a dozen uses.

Has anyone had a similar problem? I don't know what to do next. I am limited in my diagnostic abilities, and I replaced the what I thought were the common problem parts. It just baffles me that it worked perfectly on all three occasions I hauled that thing out of the wall, tore it apart, replaced one little thing, put it all back together and slid it back in place only to fail again after a couple of days.

What am I missing, besides a brain?

Please and Thanks for any help,


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Appliance Tech - Moderator
Staff member
Jul 11, 2006
Murray, Utah 84107, United States
The high side components are all good since it works for a few days. Most likely the control stops sending 120 VAC to the primary side of the high voltage transformer. There's probably a broken solder joint somewhere on the board or a glitch in the on board MICOM. Moving the machine around probably makes it work. When it stops working, check for 120 VAC on the primary side of the HV transformer. If there's no voltage the EOC is faulty.

Unfortunately the control board has been discontinued and no longer available: