Wondering if anyone can help with a busted microwave.

Whirlpool GMH3204XVS-2 - built in 2010 - put in service 2012.

Stopped working during a cooking cycle. At the time no noticeable noise, or smell.

If I run it at a lower power level (like "5") I can hear the "swell" of the transformer that I usually hear when it pulses for lower power levels.

I pulled the diode (CL04-12) and tested it - based on what I've read it seemed like it might be OK - but the voltage drop across it was high (I was reading about 5.3 volts through a 9V battery). Resistance was rather as I've read as well (high both directions, really high in one).

I tested the cap - not swollen, it seemed within rage (I forget the rating - maybe 1.05 and I was reading 1.03), internal resistor appeared to be draining as designed.

I tested the magnetron - and again it seemed to be OK (no opens, no shorts, about .3ohm resistance). No visible cracks, etc - but there is some minor discoloration near the base (the metal mesh) of the "tip"

So I put the diode back in - and when I powered it there was a single arc to ground from "near" the diode. I could have been from the diode itself - or it could have been from the wires on the cap that were on the same terminal as the diode (more on this below).

Thinking the arc was from the diode I decided to replace it since it's cheap.

As soon as I powered it on with the new diode there was again a single quick arc - this time it looked like it came possibly from the transformer (what looks like a tap in the windings to a thermal switch on the magnetron??) - OR - from one of the leads into the magnetron, the bottom most lead being the same one that comes out of the cap where the diode connected (and it arced previously).


So I really have no idea what could be wrong. But I am wondering it it's not the magnetron based on the 2 times I've seen an arc and the arc coming from a wire that attached to the HV cap. :confused:

Any advice appreciated.

Cheers -
Don