Franc Zabkar writes:
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
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.
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.
--
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