Microwave runs for 3 seconds and stops

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:

http://www.microwavecontrol.com/safety.htm
http://www.microwavecontrol.com/disassembly.htm
http://www.microwavecontrol.com/doorsw.htmH95, H97, H98 or H99 mean that there's a problem with your inverter, magnetron, or digital programming circuit.
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
[email protected]
http://www.MicrowaveControl.com
Microwave Oven Control Panel Repair Nationwide "Recycling by repairing since 1982"

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:

http://www.microwavecontrol.com/safety.htm
http://www.microwavecontrol.com/disassembly.htm
http://www.microwavecontrol.com/doorsw.htm

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
[email protected]
http://www.MicrowaveControl.com
Microwave Oven Control Panel Repair Nationwide "Recycling by repairing since 1982"

Dan, That unit has an inverter, that is the power source for the part that puts out the Microwave energy called the Magnetron. The inverters are expensive and I stopped doing warranty work for Panasonic beacuse of them. Some pencil pusher somewhere though it was a great idea to replace 3 common fairly inexpensive parts. with that dang inverter. Microwaves have come down a lot in cost, I would buy a new one without an inverter. Sorry, wish I had better suggestions, I DO NOT LIKE THEM. LOL Sorry! Panasonic and their distributors are always out of them and there so expensive no one wants to stock them. I have had new ones sent to me that were already bad.

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 it stops at 2-3 seconds, 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 http://031d26d.namesecurehost.com/mwd/safety.txt http://031d26d.namesecurehost.com/mwd/disassembly.txt http://031d26d.namesecurehost.com/mwd/doorsw.txt

Otherwise, 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.

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 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.

We're happy to help you with free advice and we'd appreciate your thoughtful rating of our answer.

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 http://031d26d.namesecurehost.com/mwd/safety.txt http://031d26d.namesecurehost.com/mwd/disassembly.txt http://031d26d.namesecurehost.com/mwd/doorsw.txt

Otherwise, 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.

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 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.

We're happy to help you with free advice and we'd appreciate your thoughtful rating of our answer.

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 http://207.234.249.73/mwd/safety.txt , http://207.234.249.73/mwd/disassembly.txt and http://207.234.249.73/mwd/doorsw.txt

Otherwise, 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.

That 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 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.

We're happy to help you with free advice and we'd appreciate your thoughtful rating of our answer.

You didn't mention your brand or model number, but I'll assume it's a Panasonic since you posted this under a Panasonic category.

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 http://207.234.249.73/mwd/safety.txt , http://207.234.249.73/mwd/disassembly.txt and http://207.234.249.73/mwd/doorsw.txt

Otherwise, 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.

If it stops after 7 seconds, it has a problem with the inverter.

If it stops at 16 seconds and is a sensor model, it probably has a defective humidity sensor.

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.

Display codes H95, H97, H98 or H99 mean that there's a problem with your inverter, magnetron, or digital programming circuit.

That 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 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.

We're happy to help you with free advice and we'd appreciate your thoughtful rating of our answer.

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. Due to the 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. We're happy to help you with free advice and we'd appreciate your thoughtful rating of our answer.

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.

Due to the 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.

We're happy to help you with free advice and we'd appreciate your thoughtful rating of our answer.

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.

If it stops after 22 seconds, that means the controller has detected a problem, usually a problem with the inverter or a bad magnetron.

Due to the lethal voltages used and produced, I do not recommend that an inexperienced person work on these.

You can find an authorized Panasonic servicer here.

We're happy to help you with free advice and we'd appreciate your thoughtful rating of our answer.