[gopherrabbit]

The manufacturing date on this one is September 1993.I bought at a yard sale several years ago.In the last few days it started taking longer to heat things up.This morning it wouldn't heat at all.The display, fan and turntable all work fine.I checked the fuse,the magnetron, the capacitor and the HV diode.Nothing smells burnt or looks like it's been hot.I used the tips from this site Complete Microwave Oven Troubleshooting, Repair and Information to test the components.I didn't use a battery on the diode but it doesn't look or smell bad.All I've got to test with is a small multi meter.I didn't find any bad circuits and the transformer checked out alright. Any guesses as to what else I might check. Oh, that site said to check the triac.But I couldn't find that any where.And the door switches work fine.I'm stumped.

[getcooking]

on a MW of that age is most likely the HV diode and or mag if your cap ck ok i would ck the HV diode with a 9V

[MicrowaveDisplaycom]

Not all magnetron failures can be found via the continuity checks you mentioned.

Experienced professionals with the right equipment will measure to be sure the correct filament voltage and high voltage are present, then if it's not cooking, the magnetron is assumed bad.

Even without measuring the high voltage, the rule of thumb is assuming the turntable and/or stirrer (as equipped) are working, the high voltage diode is not shorted or blown, and the line voltage is proper, when a microwave is heating poorly, it's virtually certain to be a bad magnetron.

This is not to be confused with the "shotgun" approach of many so-called technicians who simply suggest changing parts until it starts working.

You can usually find helpful exploded view diagrams and order parts by entering your full model number here.