My microwave kenmore 66222500 makes a humming sound like if it was on when the door is closed. i have to unplugged it or leave door open to stop the humming sound. I tested the magnetron, the primary and secondary switch, the capacitor, the diode and everything is ok. It heats food ok. But cannot find the source of the humming sound. I do not know how to test the heat switch. Can anyone help me? Thank you.

SOURCE: Microwave heats but slowly.

This is the second time I have requested assitance on this site with no response. The beginning of this thread dates back two months. Why would I ever want to pay for support when it is so poor at this level?

SOURCE: No Heat

ALL functions work.... just no heat? Is that right? I am assuming that the control (computer?, relays?) ARE supplying power to the magnetron.

IF everything checks out as you say, is the magnetron filament O.K.? (You have to disconnect it from the transformer to test it.)

If the magnetron transformer draws 8 amps, it sounds like it's O.K. cause if it was shorted, it would blow a fuse, and if it was open, it wouldn't draw ANY current.

Check it out, tell me more and let me know. No heat means the Magnetron isn't working.

William Miller

• 9179 Answers
• Posted on Jul 01, 2008

SOURCE: KENMORE MICROWAVE (HOUSEHOLD) LOCKED

It sounds like you press STOP two or three times to lock it. Maybe that (or another key) will unlock it.

The lock / unlock procedure will be covered in your owner's manual.

Or you can try a hard reset - unplug it from the wall for one minute, then plug it back in and try again.

If you don't have your manual, you can get one here. (Enter your model number without any spaces)

We're happy to help and we appreciate your thoughtful rating of our answer.

SOURCE: Kenmore over the range microwave

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SOURCE: LG MS-2143RSL MICROWAVE OVENT NO HEAT

hi i am suggesting that it is probably the magy as the res to grndis a bit low and therefore loading the sec supply down , just a thought
cheers grant