Burning Smell in microwave/convection oven

Assuming your inside light and turntable come on when you try to microwave, with the symptoms you have, I would most strongly suspect a shorted high voltage rectifier diode or a bad magnetron, or a loose and possibly corroded connection on the magnetron's terminal.

If it's within the magnetron portion of the warranty (usually 5-9 years) but out of the original full warranty (usually 1 year), then your manufacturer will cover the part cost, but not the cost to visit you or the labor charge to do the work.

GE Customer Service is here.

Otherwise, the diode is a fairly cheap fix, and the mag will cost more.

If you or someone you know decide to look into it, we have critical safety information and disassembly information at our site, and our link is at our listing here on FixYa.

There should be a "mini-manual" (tech sheet) hidden inside the unit behind the control panel or hidden on the left side behind the grille, which is very helpful when troubleshooting, testing, and locating components.

At our Web site, we have a video available showing how to remove a typical over the range control panel assembly in under 5 minutes.

You can usually find helpful exploded view diagrams and order parts by entering your full model number here.

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

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