The microwave runs - lights, motors, fans, and transformers, but not the magnetron. I've not been able to find a schematic, so troubleshooting is random. The HV diode tests bad as does one of the thermostats - the one on the case for the HV transformer - this assumes that this thermostat is normally closed, it tests as open. There are no signs of high heat or arcing anywhere. All three door switches change state when the door is opened or closed. I could simply buy both parts, but am afraid that another undetected problem caused these to fail, as having two unrelated components fail at once is not likely in my mind.

Thanks for the reply. I've since tested the thermostat and it is, in fact, a normally open model - closes when it detects heat - so it is not bad. Therefore I'm down to one component bad and that makes more sense. Now it is just finding where I can pay $30 for a $4 diode without waiting a week.
This would be much easier with a schematic, why are they so hard to come by?

Thanks once again for your reply and especially for the schematic. You have been very helpful and I do appreciate it. The part has been ordered and I'll update the forum with the outcome.