Today's Adventure
Hi Rick,
I went back today and opened up the unit as before; removing the control panel for better access to the door switches.
I found only three switches; top, lower middle and bottom.
I removed the connections to the top switch and checked the terminals with an ohmmeter.
I don't remember exactly which way it went, but clearly the switch was closed one way (door closed, I think) and open the other way.
Next, I removed the connections from the middle switch, which I took to be the "monitor switch".
The switch read closed with the door open and closed with the door closed. It looked like I was on to something.
The bottom switch tested good (i.e. different with the door open than with the door closed).
I also noted that the middle switch was especially floppy in its opening in the long switch bracket; more so than the other switches were.
I thought something might be broken to cause this, but I have come to change my mind.
The wires connect to the switches through (what I will call) a plastic connector.
The plastic connectors are fused together so that both switch connections must be made or separated at the same time.
Also, these connectors fit tightly in the switch bracket so that when they are connected, the switch is pretty much locked into position,
unlike its "floppy state" with the connector off.
I removed the switch bracket and released (what I assume to be) the monitor switch, which looked to be in good shape.
I "bench tested" the switch and it tested good (Normally on with the button out; off when I pressed the button in)
I reassembled the switches in the bracket and mounted it to the chassis again.
I wanted to test that switch again (door open vs door closed) but this time with the plastic connectors on it, but I am reluctant to cut a wire.
I was not able to release the wires from the connector, which I have often done with a tiny flat screw driver.
Ultimately, I jammed a piece of thin wire into the back of each connector terminal so that I could monitor the resistance with the connectors on the switch,
even though the wires were still connected to other parts of the unit.
Under these conditions I would not expect to see the resistance change from about zero to infinity,
but I did see a clear change (increase) in the resistance reading when the door was closed.
I think I have convinced myself that the monitor switch is working properly.
I did not think it prudent at this point to invest another fuse to see if the unit had somehow repaired itself.
While the unit was open, I noticed two round components at the bottom of the opening, which I took to be thermal switches (possibly?)
They each had two terminals, so I figured I would test them, in case it might provide some useful information.
The one on the left tested "closed" and the one on the right tested "open" (for what it is worth).
So, my friend has found that Best Buy has what appears to be the same model microwave oven on sale for about $200.
I am assuming that the wall bracket already in place is the same, which would make the mounting of the new unit pretty easy.
Do you think we're getting close to that option?
Chartman