Is there anything else that could be damaged that does produce heat besides the magnetron?
There are a few different parts that can cause a microwave not to heat. The diode, HV transformer, Magnetron, thermal fuse, capacitor and stirrer.
The microwave doesn't heat up, everything else works, light ,turntable, clock, motor is running but makes a louder noise than usual.
Answer Hello Max. Based on the information you provided, it sounds like the magnetron [AP4301392 and the diode 5304467670 are bad and will need to be replaced. Hope this helps.