I have a Maytag over the range microwave that suddenly died last week. I’ve been trying to diagnose the problem, but haven’t had any luck. Here’s what I know.
The power outlet is good.
The 2 internal fuses are good.
All of the thermal cutoffs are reading properly according to the schematic in the mini-manual found behind the control panel.
The HV Capacitor doesn’t seem to be charging, but I think that is due to the high power relay not closing because of the dead control panel.
The HV capacitor seems to read properly when I apply an ohmmeter.
The HV diode is good.
All 3 interlock switches are reading what they should when the door is open and closed.
The magnatron appears to be reading properly according to the test procedure in the mini manual (less than 1 ohm across terminals).
The HV transformer seems OK, but I’m not sure If I am testing it properly because the picture in the manual doesn’t quite match the transformer in the microwave.
I’m getting voltage out of the filter circuit board where the fuses are located.
At this point, I think that either the control board isn’t getting voltage, or that something has died on the main control board, I’m just not sure where to continue checking because I can’t figure out which wires are suppose to supply voltage to the circuit board. I did find 2 capacitors on the PCB that are reading open, and am assuming they should read low resistance, then up to infinity, when I attach my multimeter, but am not sure how these particular capacitors should read. One capacitor is a disk type (sc472m) and the other is a larger film type (PCX2 335M MKP).
Any ideas on what might be wrong, or what to check next?
Thanks.