Hi,
I’m new to this forum and have ZERO familiarity with the inner workings of microwaves. My microwave doesn’t always heat the food. Sometimes it works, sometimes it doesn’t…unpredictable. The light, turntable, power, buttons, and fan all seem to work fine. Any ideas on which part is going out and if I can replace it? Would really appreciate any help I can get 
[quote=amcintosh;150686]Hi,
I’m new to this forum and have ZERO familiarity with the inner workings of microwaves. My microwave doesn’t always heat the food. Sometimes it works, sometimes it doesn’t…unpredictable. The light, turntable, power, buttons, and fan all seem to work fine. Any ideas on which part is going out and if I can replace it? Would really appreciate any help I can get :)[/quote]
Usually if a microwave isnt heating it is the magnetron. It can be tested with a multimeter. Set the meter to ohms 1k test between the two termnials.(uaually a PINK and a RED wire) meter should go to zero. Test between each termnial and the magnetron housing. meter should show open circut. if it does magnetron is good. There is also a diode that comes off from the capacitor and sometimes burns out. No real way to test the diode. It costs About $8.50 while the magnetron cost about $54.00. There are also some thermostat switches in there that can be tested with a multimeter(ohms 1k) post to post the meter should read 0 resistance. These switches run about $17.00. Be careful working around the capacitor and other electrical compoents as they often hold electrical charges even while unpluged. To purge them from electrical charges use a insulated screw driver and arc it betrween two posts. It will "POP" purging the electrical charge. If you need part # I have them just ask. Best of luck:) !