Continuity checks showed the flame sensor was open. Schematic notes it opens at 217 degrees and closes at 30 degrees. Removed sensor and placed in freezer for twenty minutes. Tested sensor and it was now closed, reinstalled and microwave worked normally. Ordered new sensor in case the original is operating at too low a temperature.
First, I read the PartsSelect DIY report by Linda, Warsaw, IN. With confidence, I purchased the magnetron. Upon receipt, I took the built-in microwave out of the cabinet, set the unit on the kitchen floor, and was stopped cold by the Safety Torx nuts on the reverse of the unit. Borrowing the right wrench allowed the 20 minute start-to-finish part changeout and reinstallation of the unit in the cabinet to proceed. The old magnetron was the defective part. Discovery of the 10-year Parts-Only warranty on the less than 10-year old unit was insufficinet to guide me to take the unit in for their Labor bill to repair. New part in hand, it just was that easy - and assumed to be no less expensive.
First I ordered and replaced the diode. That did not help. Then I ordered both the magnetron and the thermostat magnetron because I didn't know what I was doing. After I replaced those, it still wouldn't heat. So I called an electrician. He noticed I had knocked a wire loose. I connected it and the microwave worked. I reconnected the old magnetron, just to test it. It didn't work. Then I put the new one back in. It's working just fine now! It took quite a while to put everything back in place because it was a built-in. But it was a lot cheaper than getting a new microwave, even with the cost of a repair man to show me I had a loose wire!
