I have a microwave and lower oven combination unit, Whirlpool model #GMC275PRS01 that is about 5 years old. The microwave makes a humming sound after using. This has happened in the past but by running it a few seconds and opening/closing the door it would stop. Recently I could not get it to stop. I tried shutting off the electric braker to the unit and then turned back on but it started the humming again. I left with it humming and a couple hours later when I got home the unit on the outside and inside of the microwave was hot. I am now keeping the braker off until I can figure out what it is. Fearful it will continue to heat and cause a fire. Please let me know what you think it is.

Rene, June 2013

Yes, it making the sound when not running. Sorry I wasn't clear. I heated an item in the microwave and opened the door and removed the item and then closed the door and heard a humming/buzzing sound. It did not make the usual sound like it does when it is running, and the turning table inside was not moving and the interior light was not on...it was just a humming sound. This humming continued while I was away from the house and when I returned a couple hours later the outside door and interior of the microwave were both hot to the touch. So whatever is making that sound is generating energy enough to heat the unit. Thanks for any input.

Rene, July 2013

also the magnetron hums as it fires

mm, June 2013

the transformer in your oven always hums,some are louder than others,what do you mean you left it with a humming??your question not make sence now. did you leave it turned on for 2 hours ?????surely not

mm, June 2013