On Sep 24, 9:09 pm, Franc Zabkar wrote:
On Wed, 24 Sep 2008 19:31:52 -0700 (PDT), poster
put finger to keyboard and composed:

http://geocities.com/anglomont/mw.jpg
What is actually the curved line close to the transformer and
directly connected to magnetron?

That's the transformer winding that supplies 3VAC to the magnetron's
filament.

What if upon disconnecting the both diodes fast fuse blows again
when eithermicrowaveor grill cooking is started?

According to Sam'sMicrowaveFAQ ...

"An open HV diode will result in AC instead of DC across the magnetron
with a peak negative value (the only one that matters) about 1/2 of
what it should be. The result will likely be little or no detectable
heat but no other symptoms".

If the fuse blows again, then I'd be looking at the power transformer
or the magnetron.

What is it exactly connected between a8-a7?

That's the transformer (and metal oxide varistor) that is part of the
low voltage DC supply for the control board. One secondary winding
supplies the +5V (?) logic, the other probably supplies the display
filament.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.


thanks for input
if the transformer secondary was shorted inside it would not be able
to supply voltage high enough to burn the rectifier diode when it was
replaced so maybe wiring is a good suspect since magnetron seems ok-
that could be tested with turning on grill operation only ?