Whirlpool model # GH7145XFT1-
Turntable, clock, front panel all work, but has this loud humming or buzzing noise and doesn't heat well. Can you help?

D. Krueger, January 2008

The microwave was not made in the U.S.A.
I had a top brand over the range microwave built for a U.S company in the Philippines, a loud buzz occurred, and it burned.
I have the same brand currently, built in Maylasia, the loud buzz is back. The combined age of these microwave units is under three years.

I bought a counter top USA built microwave in 1980. It still works very well.

cassandra, December 2012

When not using the microwave the motor for the fan sounds like it's on when the fan is off? Can you help me with this problem? I cleaned the filters and that didn't help! Thank you

Lynne Milnes, June 2011

This guy has an extensive trouble shooting guide for this problem. If you have an electrical test meter, you can find the bad part:

http://www.repairfaq.org/sam/micfaq.htm#mictsimp

Rockie, January 2008