On 03 Mar 2009 19:34:24 -0500, (Samuel M.
Goldwasser) put finger to keyboard and composed:

Aside from the reliability issues which have been addressed in other
replies, it's possible that the HV diode died for reasons unrelated
to the inverter.

I'm not sure where to look except for the magnetron.

Page 20 of the following service manual has a detailed circuit diagram
of the inverter:
http://www.eletrodomesticosforum.com...c_NN-G62BH.pdf

Page 42 of this manual has a block diagram of the controller chip:
http://rc5.ru/upload/panasonic_mw_NN-C2000_(MWO).pdf

What does the oven do when you go to "cook". If nothing at all, then
there are almost certainly other bad parts, a fuse at the very least.

I didn't test it in case something else broke, but my brother tells me
that everything appears to work except for the actual heating. That
is, the control panel works, the turntable turns, and the fan spins. A
shorted HV diode (there are two in a voltage doubler arrangement)
would mean that one of the 8200pF caps is now connected directly
across the secondary winding. I expect this would overload the
transformer and presumably the inverter would sense this fault
condition via the current transformer in the primary circuit. I'm told
that the oven shuts down after a time. Anyway I've ordered the diode
and I'll report back once I've tried it.

- Franc Zabkar
--
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