Microwave not heating food.

[jimwrye]

Kenmore 721.800 series Microwave running fine but not heating food.

Power supply, magnetron, high voltage diode, capacitor, and transformer all test good.

In need of guidance. Appreciate all I can get.

Jim

[MrApplianceMatt]

Door switches are often overlooked in these situations. Also, make sure the control is sending power to the transformer.

[Vance R]

Check the amperage draw while it is supposed to be heating. Let us know the amp draw.

[jimwrye]

About 9 amps

[Budget Appliance Repair]

11 minutes ago, jimwrye said:

About 9 amps

Points to a bad mag tube - the mag tube is the the one part that you can check with an Ohm meter and it will check all OK and can still be bad.

At 9 amps - the high voltage circuit is being power but never kicks up to full amp draw because the mag tube never starts it's oscillation.

Disconnect the two wires to the mag tube and make sure they are away from anything and run it again - if the amp draw is he same with the mag tub disconnected you can be pretty much sure the mag tube is bad.

After you run it for about 20 - 30 seconds unplug and carefully with an insulated screwdriver you can short across the capacitor terminals and will get a load bright spark - that also proves the high voltage system is outputting and charging the capacitor but the mag tube doesn't start it's oscillation process which would kick the amp draw up to around 11 - 13 amps.