That would be an inverter issue. Here's my overview of Panasonic microwave faults:
Diagnosing Panasonic microwave oven stoppages:
If it stops after 22 seconds, that means the controller has detected a problem, usually a problem with the inverter, controller, magnetron, or a bad connection from one or the other.
If it stops at 16 seconds and is a sensor model, it probably has a defective humidity sensor.
If it stops after 7 seconds, it has a problem with the inverter.
If the digital programmer circuit / controller does not get a feedback signal from the inverter for a period of 3 seconds, the controller will stop the cook cycle.
Or see if this describes what's happening:
Put in time, push start and unit runs for 2 seconds, relay clicks, unit goes off. Cook time on display goes off and clock time comes back. Bad upper interlock switch and charred connector. If so, see:
It may be a loose connection in the wiring between the inverter, magnetron, and/or control board, or maybe one of those components has failed.
Due to the complexity and lethal voltages used and produced in inverters, I do not recommend that an inexperienced person work on these.
You can find an authorized Panasonic servicer here
In Canada, you can find an authorized Panasonic servicer here
Got more questions? Please contact me directly for full details since FixYa doesn't always inform us of follow-up questions. Remind me of the full model number and FCC ID number from the tag and your detailed symptoms.
- William E. Miller, AS-EET
Microwave Oven Control Panel Repair Nationwide
"Recycling by repairing since 1982"