My panasonic Inverter NNSF microwave goes off after 30 seconds with no heating. No h9 comes up.

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.

Hello

Unplug the microwave and plug it back in after 30 seconds to make sure the message did not appear because of a simple glitch. If it does not come up again, use the microwave as normal.

The "H98" error means that the microwave's inverter has shorted out and does not work any more. The microwave cannot transfer power to create heat, and the part has malfunctions and requires replacement. Use your microwave serial number and customer service to find the proper part for the microwave.

Your microwave comes with a warranty that will cover the inverter if the warranty is still valid. Call the number for the warranty department or bring the microwave, with receipt, back to the store you purchased it from. This will save you the hassle of replacing the par

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 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.

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.

If yours is not a Panasonic, please reply back with your brand and model number so we can help you.

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.

HI, this is an inverter board issue. the magnetron would not shut down the unit. if the magnetron was the issue, it would continue to run but, it would not heat.

replace the inverter asap.

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 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.

Is it 30 seconds or 22 seconds?

The 22 seconds is the giveaway.

In most cases, this is 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.

I would recommend that you contact your nearest Panasonic-authorized servicer. You can find one here.

We're happy to help and we appreciate your thoughtful rating of our answer.

If the screen is showing a fault number or a number you havent seen before then its probably a program fault which can't be fixed. Check that the vent holes on the back of the oven aren't dirty and ensure that the whole oven is clean inside. Sadly it sounds like a program fault which cant usually be fixed by the owner though.
Finding a Panasonic oven repairer in the UK shouldnt be a problem though. My parents had a simlar problem wth their Panasonic Inverter oven, called the UK customer services and Panasonic contacted an authorised repairer in Scotland to visit them. Call customer services on 0844 844 3868.
If the call out charge exceeds £80 then you're probably better off buying a new oven. 

In this as in other inverter models, shutting off after 30 seconds (more like 20 in most cases) is usually a symptom of a bad inverter or magnetron. Due to the lethal voltages involved, I do not recommend that a person without training and experience ever work on these models. You should be able to locate a Panasonic-authorized servicer here: http://www.pasc.panasonic.com/WhereTo/FindServicer.asp?Pass=1 I would mention the exact symptom when you call so the technician can bring a new inverter and other parts with him when he comes out to repair it. Might save you having it pulled into the shop. If you or a friend insist on trying to work on it, we have *critical* safety, disassembly, and troubleshooting info at our site, which is linked at our listing here on FixYa: http://tinyurl.com/yzjozk You can order parts via Panasonic at http://www.pasc.panasonic.com/epartr