The repair was very easy, however the bulb was not the same as the original one. The original bulb had a bright setting and a low setting, but the replacement bulb was only the low setting bulb. There was no bright and dim operation. The switch on the microwave had the duel settings.
The high voltage tired was shorted. I replaced it with a new one, but that did not solve the problem.
You can test the high voltage tired with a voltmeter and a 9 V battery. Search Search for it on YouTube.
You can also test the high voltage capacitor, the high-voltage transformer, and the magnetron with a multi meter. Search for the procedures on YouTube.
I tested all these high-voltage components with a low-voltage multi meter, and they all checked out OK (after replacing the diode). However the microwave still did not heat food.
When working on a microwave it is important to unplug it and also discharge the high voltage capacitor. The capacitor has a 10 megaohm resister to automatically discharge itself, but it may have failed – – so discharge it manually.
With microwave still attached under the cabinets, I removed 2 screws for the top grill and then one screw for the bulb cover plate. This provided access to the bulb. The replacement bulb was a simple plug-in.
The best part of this experience was the exploded parts diagram on the PartsSelect web site which allowed me to easily locate and order the correct part.