Wife let me know the microwave was making grinding noise while I was in garage fixing her car starter, never a dull moment. Further questioning she also said it wan't heating the food. Due to being an odd sized built in $$ unit I had to have repaired. I was getting quotes in the $4-500 range for just the magnetron.
I was pretty confident the magnetron was the issue and also ordered a new capacitor and diode since I was going to be in there and a lot of money ahead repairing myself. About 15 screws on the unit's sheet metal case with a cordless drill to remove & I had complete access to the internals. A little daunting shorting the capacitor prior to digging in for the repair, the unit sat for about a week and the internal capacitor's resistor must have discharged the capacitor since it didn't even spark when I crossed the terminals. NOTE: do not trust the capacitor will self discharge as designed incase it too is faulty, they still need to be manually discharged, if you absorb the voltage it may be the last thing you do.
6 screws removed the plastic shroud over the magnetron as well as a bracket that holds the capacitor. There were 4 harnesses to unplug and 4 nuts holding in the magnetron. It was pretty simple and designed for servicing. GE had a 10 year warranty on the magnetron I believe and typical GE product it was 10 years old and just out of warranty.
I ordered parts at 4:00 p/m on a Thursday and Fedex delivered them the next day at 9:30 a/m. I will be ordering more parts from AppliancePartsPros.com in the future if I need them, all GE OEM parts, great pricing and delivered Jimmie Johns fast!