I was able to locate and fix my problem despite not getting any advice from this forum.

For those with a similar 'no more heating' problem, here is what I did to at least isolate the problem:

1) I turned on the microwave and try to heat. I measured for 120 VAC at the front side of the high voltage transformer. Once I got this, I knew my board, relays, door switches were all allowing the microwave to TRY to heat. If you do not, then the problem is likely upstream from the high voltage xformer.

2) I then checked each; CAP, HV XFormer, diode/rectifier, and magnetron

3) check the capacitor

4) Just replace the diode

5) check for continuity of each; magnetron, high voltage xformer and resistor (within the cap).

I ended up getting good continuity for all items I checked, but suspected my magnetron was bad because the others looked GOOD, and it looked sketchy. NO weird noises, burns, or other tells, but it was bad, was replaced, and not hte MW works again.