Symptoms: The microwave runs just fine, but nothing warms up no matter how long you put it in for.
Troubleshooting: The transformer seems to be fine. The capacitor looks fine (to be fair, I didn't meter it, cause it is hard to reach) The magnetron has been replaced twice... It always seems to fix the problem, but after two or three weeks it stops working again. I don't see any charring on or around the magnetron like it is overheating. The large magnets don't appear to be cracked. In fact, once I remove the apparently bad magnetron, I meter it out, and it looks fine... but I put a new one in and it works again for a short time. It doesn't seem like a power issue, transformer, capacitor, diode... It seems like it's the magnetron, but I don't want to keep replacing it every month. Any ideas?