I replaced the magnetron and diode last summer ... there was a loud humming and the diode smelled burned. It's worked perfectly for 16 months. This week it stopped heating.

Control board works fine.
The light, turntable, HVT fan all run when started.
NO loud humming like a bad magnetron.
NO burning smell anywhere.
There is 120v across the two HV fuses.

The troubleshooting flow chart is a bit of Greek, it says I should "check voltage across power relay on pcb"? How? Is there a way to check the magnetron with an ohm meter? Possible bad TCO? I recall replacing one of these before too.

Thanks in advance!!