OK, I see there is a long history of microwave over repair questions. But I don't seem to see a thread that has my question:
So I have an older GE JVM1190 over-the-stove microwave unit.
Symptom is no heat.
When powered up and programmed to cook, the unit makes the expected humming noise (the same it's always made) but a cup of water in the chamber will not heat up.
I've studied the microwave FAQ repeatedly and I believe I understand the dangers.
I constructed a long wooden-stick-based discharger for the HV cap, discharged it (didn't get any spark at all), then ensured there was no residual voltage on either of its terminals. Then I shorted the terminals.
First I "tested" the magnetron: infinite resistance from either cathode connection pin to ground, very low resistance between the two pins themselves. Seems OK.
Then I tested the HV diode by placing it series with a 390 ohm resistor and applying 15 VDC, and meauring the voltage drop across the device. -15V negative biased, about 10 VDC forward biased...this seemed to be within range.
Finally I tested the HV cap. It reads infinite resistance to the chassis from either terminal. Between the terminals my capacitance meters reads around 0.86 uF... which seems to be correct.
I've heard mention of a possibly bad HV fuse. AFAICT, this unit doesn't have one of those.
So...the HV cap seems good, the mag seems good, the diode seems good, the unit seems to draw appropriate current when in cook mode,yet the over won't heat food.
What am I missing???
Could the magnetron still be "bad" despite the fact that it doesn't read shorted/open?