My sister-in-law was using the microwave to melt a large tub of wax (bad idea), and the microwave suddenly powered-off and wouldn't come on (thermal cutout, I assume). After awhile, the power was restored (it cooled off, I assume) and everything seemed to work (lights, turntable, fan, noise), but it won't heat up food anymore.

Is it possible that one of the thermal cutouts could cause this behavior, or is my magnetron/diode fried?