Microwave runs but does not heat. I have checked fuses, door switches, capacitor, diode, magnetron, and transformer and all test OK. I did find a scorch mark on the wire on the output side of the thermal fuse but both the wire and the fuse had continuity. My testing showed that there is no a/c power going into the transformer. Could the Main Control Board be the problem? If so, is there any way to test it? Thank You.

I followed the test procedure that was on the literature that was tucked behind the Control Board. The testing was pointing toward either the Control Board or Transformer. But then microwave heated the cup of water I had placed inside. Loose wire? Reset Relay?

Can I replace the relay or do I have to replace the entire control board? If the relay is replaceable what info do I need from the relay body? There is a lot of info printed on it. Thank You.

The microwave is working now. I was guessing it was the relay as the manufacturer's trouble shooting flow chart said to check it's voltage. Would testing reset it? If the relay requires soldering then I'm out of luck.....I don't own soldering equipment and have never soldered. If the microwave fails again I'll just buy a new one or replace the failed part. It's an over-the-stove model so a little more expensive than a counter top model.

Another thing that I saw was the plastic that housed the female disconnect to the Thermal cut out fuse was burnt. The fuse tested fine. I'm wondering if the fuse's male blade wound up between the outside of the female part and the plastic insulator. The fuse blade is a little loose so I've ordered a new fuse.