Microwave no longer heats up food

A model number would help us help you pretty specifically, but without it, here's a generic answer.

Generally, the most common causes of a failure to heat are:

- bad door switches or door switch mounts
- loose or corroded connection at the magnetron
- problem or loose connection on the control unit circuit board
- bad magnetron
- shorted high voltage diode

If the inside light, turntable, and internal cooling fan are not working, then it's probably a door switch. See my door switch help file here.

If the inside light, turntable, and internal cooling fan are working, then the problem is likely in the high voltage section.

In that case, here are some links you or someone you know can use for test help, but read their safety warnings first:

http://www.gallawa.com/microtech/diode.html
(if it's not shorted or burned, it's probably okay)

http://www.gallawa.com/microtech/mag_test.html

http://www.gallawa.com/microtech/xformer.html

http://www.gallawa.com/microtech/cap_test.html

You can find links to helpful exploded view diagrams and order parts here.

I'd recommend that your bookmark this link to your favorites.

We're happy to help you with free advice and we'd appreciate your thoughtful rating of our answer.