• ** 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 micro oven combo humming


Premium Member
Nov 27, 2022
Model Number
More than 10 years
In a home I just moved into, I have an issue where my wallmount Whirlpool microwave/oven is humming constantly -- definitely coming from microwave & only way it stops is if I disconnect the power breaker (opening/closing door has no effect). Other observations/notes:
  • It's around 20 years old/seems well maintained
  • I use it to roast peanuts & in this one it takes significantly longer than others I used (6min vs 2min)
  • It passed water heating test outlined in manual (heating 16oz of water for 1min raised it 40 degrees F
  • Sounds normal when it runs (the humming is very quiet, so it masks it)
See video where you can hear it at rest & when I start:

I think I can manage to pull it out & reach the internals -- any idea what component to try to replace? Could it be the magnetron given the water heat test passes & only a low level hum even when not operating?
Rick @rickgburton has been out sick since Jan.12th 2022 with a serious illness, we are hoping and praying for a speedy recovery!

Rick is our Microwave expert, so unfortunately you'll have to wait for him to return or hopefully another tech. or another member that's run across this problem, can help you here.
Thanks, he will appreciate that when he returns!
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