Kitchenaid microwave/hood , magnetrons burn out

[QFMaint]

The model # is ; KHMS2050SSS2 . Its about 3 yrs old. The magnetron antenna burned up which also smoked the thermo-switch. I replaced both and it burned up again immediately. Anyone have this problem with this model ? The components look different than the usual. The transformer looks to be on a circuit board and I'm not sure where the cap. is . Also can't find any repair manual for it . Send Help ! Thanks

[tgoods]

When you say immediately, do mean within seconds?  Is it arcing in the wave guide? Maybe your inverter board is bad.  Whenever I've seen bad inverter boards, they've always had no output. Maybe you have one that has too much output?

[QFMaint]

Thanks for a reply .
Yes the magnetron goes within seconds. It has a louder than normal hum and you can just tell something is getting Fried . I can't see in the wave guide .  My thought also was that its getting way too much power.  Don't know where to start though . Can't find any service info, schematic, nothing. I'm new to microwave repair, but with a little info on what I'm looking at, I can usually figure things out. I'll guess the 'inverter board' is what the transformer is sitting on. It's a 4"x4" circuit board and the red wires going to the magnetron come off the edge of it . It has a lot of other 'parts' on it too. One other thing, I noticed a nick in the paint inside the microwave on the bottom . There is a minor bit of exposed metal . Never saw any arcing though so for WIW. ?
Thanks for your help.

[JWWebster]

Is the window in front of the magnetron cracked? any moisture getting on the antenna blows m up too.

[RegUS_PatOff]

Kitchenaid KHMS2050SSS2 Inverter M/W made by Panasonic
RUN AWAY !   

[Bailey]

I was told by a  parts person at Globalmicro to change the inverter board and the mag together. You can buy a new over the range micro for $200.
Microwaves are very close to being throwaways.

[QFMaint]

Thanks guys, 
JW         There is no window by the mag. It has a wave guide across the top.
RegUS   Sometimes I wish but I'm determined to know
Bailey    Where do I get the inverter board? Its not listed on anyones website. I can't throw this one away, its an $800 microwave.

[AJ]

Where do I get the inverter board? Its not listed on anyones website.

Click on the links or photo below for more info such as pricing.

Diagram & Parts for KHMS2050SSS2

Inverter Board Part # W10217711


Magnetron Part # 8206079

[QFMaint]

Anyone have or know where to get an electrical schematic for this microwave ??  Yes , i've spent hours searching the internet with no luck.

[JWWebster]

This guy is pretty cool:

[AJ]

Here is the tech sheet. It has a schematic.
Hope that helps.

Let us know what you find.

[Bailey]

Inverter technology. All that means is they found a way to make them cheaper!

[RegUS_PatOff]

... I can't throw this one away, its an $800 microwave.

yes, you can ..
here's an excerpt from a similar Panasonic Inverter M/W repair info

With the cover off the microwave oven and CRO connected,
the control and status signals were measured with the oven operating.
The Control signal turns out to be a TTL-level 220Hz square wave
where the duty cycle determines the “Power” from the Magnetron.
The Status signal from the PSU is a 110Hz square wave with a fixed 50% duty cycle.
 This signal seems to be present when there is a current drain,
probably to signal that the Magnetron is warm and operating.
The Control and Status signals are synchronised to each other,
but bear no relationship to AC mains frequency or phase.
Here’s a picture of the CRO trace showing the control signal (top)
and the status signal (bottom).
 
2-channel oscilloscope waveforms:

[QFMaint]

AJ ,  Can't open file .  Small window shows " File is damaged and cannot be repaired"   Can you try again ?  Thanks

[AJ]

AJ ,  Can't open file .  Small window shows " File is damaged and cannot be repaired"   Can you try again ?  Thanks

That's strange, just tried it again and it still works fine for me.
Anyway here is another copy.