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.