On Sep 30, 1:49*pm, Tony wrote:
Stormin Mormon wrote:
The couple I've done, it's been the high voltage diode that
goes.

Well I sent them to you since I stock micro switches but no HV diodes.

Curious, what are the symptoms of a bad diode? *I just thought about it,
I suppose they (almost)never short out, and an open one may act as if
the oven was working but nothing gets hot?

The diode is in a simple partial voltage doubling circuit. If it dud I
think you'd get AC at reduced voltage on the magnetron? Probably not
high enough to produce microwaves?
In simple terms IIRC the HV capacitor (usually about 0.8 mfd.) charges
up on one half cycle (60 hertz) and then discharges on the opposite
half cycle in series with the already charged capacitor. Thus
providing pulses of HV DC at approximately twice peak voltage of the
transformer HV winding output.
A recent bench test showed that one particular transformer had a 21:1
ratio. So with 115v RMS into the primary, the HV would be 2415 RMS
and somewhere around 3400 volts peak. Double that minus some losses
etc. we are looking at around 5000 volts DC.
And unlike the HV in a colour TV which is a few milliamps or even
microamps to a picture tube CRT, in a high impedance circuit, the
power fed to a magnetron can be a quarter to half an amp or more; at
around 5000 volts DC!!!!!!!! Anything from 750 to 1500 watts etc.
Welcome to your own private electric chair; eh?
Cheers.