My brother's Panasonic model NN-ST756W inverter microwave oven failed
after one year, just out of warranty. I found a short circuited HV
diode, D702, UX-C2B. The associated 8200pF 3kV capacitor appears OK,
as do the inverter transistors.

The inverter PCB (240V version) is similar to the one in these service
manuals:

http://www.eletrodomesticosforum.com...c_NN-G62BH.pdf
http://rc5.ru/upload/panasonic_mw_NN-C2000_(MWO).pdf

Here are several exploded views and parts lists:

http://www.prime-electronics.com.au/...VEN%20ASSY.jpg
http://preview.tinyurl.com/bre9kh

http://www.prime-electronics.com.au/...DUCT=MICROWAVE
http://preview.tinyurl.com/ahr8s8

I'm wondering if inverter microwaves are any less reliable than
traditional transformer/capacitor types. They seem to be overly
complicated for what they do. I understand that they cook more evenly
in low power modes as a consequence of not having to pulse on and off
like conventional microwaves, but I'd rather not pay a reliability
penalty for this feature. BTW, once the microwave is sitting on my
bench top, the extra weight of a traditional mains transformer is of
no consequence.

The Microwave Oven Repair FAQ appears to bear me out:
http://www.repairfaq.org/REPAIR/F_mi...tml#MICFAQ_019

- Franc Zabkar
--
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