Testing a magnetron from a microwave with an analog meter.
Note before testing any components inside of a microwave, be sure that the unit is unplugged and the high voltage capacitor has been discharged.
When testing a magnetron, keep in mind that there is no complete way to test the magnetron electrically, but there are some things to look for that clearly show a magnetron needs to be replaced.
Looking at the magnetron itself. Making sure that the magnets inside are not cracked. The antenna on the other side is not bent or damaged and it could be burnt. If we do end up with a burnt antenna, we will want to check the waveguide. If the waveguide is damaged, you’ll want to call your manufacturer and get the unit condemned.
The only test with a meter that we could do with the magnetron is read less than one between ohm between FA, and F. Which is our filament and filament anode. Set your meter to R times one. Calibrate and place your meter leads across F and FA. Looking for less than one ohm. You’ll also want to set your meter to R times 10K and calibrate. Checking each terminal of the magnetron to the magnetron itself. Looking for no reading. If you should get a reading, the magnetron has shorted. If you get no reading, the magnetron is open.