Thanks Gene,

I tested everything except for the switches.

Couple questions first:

1) How do you test the switches? the 2 switches that are activated when the door closes have 3 leads coming off of them. I'm not sure what leads to touch with the MM and what i'm looking for. (continuity or no continuity??)

2) I'm using a Digital MM rather than an Analog MM. The instructions state to set the MM to R x 1 or R x 1K. What is the equivalent value on a digital MM? My meter has values of 2M, 200k, 20k, 2k and 200.

3) What should i do with the wiring diagram you attached to the post? i have no idea how to read that thing :)

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With that in mind, I went ahead and check everything but the switches the best I could and just tested each component using multiple values. Here is what I found.

- Magnetron: Appears to be OK. I got the same reading as stated in the instructions.

- Capacitor: Appears to be OK. When I touched the leads to the terminals, the MM would "jump" to several ohms then quickly go back to 1 (1 is infinity correct?) When i touched the leads tot he terminals and the chassis, the MM read 1

-Transformer: Seemed to be OK but i'd like to test it again after you tell me what the R X 1 equivalent is an my DMM. Also, when the instructions say touch one lead to the chassis, does that mean touch it to some metal of the microwave frame or touch it to the transformer itself?

-Diode: Best I can tell, this is BAD. The MM reads 1 no matter which way I touched the anode and cathode. I couldn't get it to read continuity (0 on the MM) no matter what I tried. Could the Diode be responsible for the microwave not heating? if so, i'm curious how the Diode would cause this problem.

-Magnetron thermostate: Appears to be OK. Has continuity. I could not find the other thermostat you said to test. What part is it in the parts diagram?

Thanks again for your help. I know i'll probably need to re-test everything once i have an answer to question #2 above.

Hi Bryan,

Sorry for the delay.

So far the diode looks very suspicious. I would recommend to test it using the instructions from one of our previous threads: http://forum.appliancepartspros...19868-diode-testing.html

Set your meter on DC voltage.

- The diode Part number: 4375349

Yes, it is good.

How to test switches? Any switch terminal is marked. It can be: COM - common, NO - normally open and NC - normally closed. When you check the switch for continuity, you have to do it twice: with the button not pushed in and with the button pushed in all the way. In the first case the correct reading is: COM-NO - open, COM-NC - closed. In the second case, accordingly, it should be close and open. The wires should be removed prior to testing.

Set the meter on 200 for all continuity tests.

The cavity thermostat is shown as #30 at the diagram.

Gene.

Hi Bryan,

The problem is that all of the above parts besides the magnetron can be tested instrumentally with very reliable test results. The magnetron still can be bad even if it did pass the continuity test. So, before you will call anybody I would recommend to order the magnetron and give it a try.

You can order the OEM magnetron or you can order the aftermarket one with the same parameters but for less money.

- The OEM Whirlpool magnetron Part number: 4375072

Last question to add to my last post.

Considering everything that i've tested to this point, if you add in the fact that the Microwave has a louder than normal Buzz when it's running, what do you think (best guess) would be causing the buzzing sound.

thanks