Dandy Designer 800 Watt Microwave

When a Panasonic Inverter Microwave shuts off after a feew seconds, it is either a bad inverter which is the quite expensive circuit board that powers the magnetron that puts out the microwave energy, or a bad magnetron, Or BOTH typically this would be a costly repair, But since it is still under warranty. You need to find a Panasonic warranty service provider in your area. If it is a counter top unit, you may have to take it to them for repair.

Mark sounds like it is tripping a internal limit relay, weak power supply or door switch possibly. Below are links to help diagnose.
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If our Panasonic microwave shuts off after 2 seconds is it likely door...

Error code H97 is an indication of a possible failure of the Magnetron, DPC board or the High Voltage Inverter board. It could be just a loose wire connection also between the DPC board and the High Voltage Inverter board.

This failure will require a service technician to diagnose and repair.

test this components and fix it. God bless you

1. Main control boardIf your microwave runs for a few seconds and stops, the first thing to check is the main control board to ensure that a shortage has not occurred. If the part is defective then it will need to be replaced to prevent continual shut offs. If this is not the issue, the next step would be to check for a faulty touchpad.
   
2. Touchpad/Control panelIf the control board is not the issue and your microwave continues to shut off after running for only a few seconds, the next thing to check is your touchpad, which is also known as a control panel. Although uncommon for this issue, symptoms are usually that the display and some buttons are working properly; however, when selected some buttons are not functioning. If this is the case the touchpad will need to be replaced.
   

follow this steps and fix it. God bless you

1. Main control boardIf your microwave runs for a few seconds and stops, the first thing to check is the main control board to ensure that a shortage has not occurred. If the part is defective then it will need to be replaced to prevent continual shut offs. If this is not the issue, the next step would be to check for a faulty touchpad.
   
2. Touchpad/Control panelIf the control board is not the issue and your microwave continues to shut off after running for only a few seconds, the next thing to check is your touchpad, which is also known as a control panel. Although uncommon for this issue, symptoms are usually that the display and some buttons are working properly; however, when selected some buttons are not functioning. If this is the case the touchpad will need to be replaced.
   

Step 1:

Door Switch

If the microwave runs for a few seconds and then shuts off, a door switch might have failed intermittently. Check each of the door switches for any signs of overheating, arcing, or burning. Also check each of them for continuity. Replace any of the switches that is visibly damaged or that only has continuity intermittently

Step 2:

Main Control Board

If the microwave runs for a few seconds and stops there may be a short circuit in the main control board. Check other components first, these boards are often misdiagnosed.

Touchpad and Control Panel

If the microwave runs for a few seconds and stops the touchpad and control panel might be defective. There are several other components that can cause this problem, be sure to check any other components before replacing this board.

Touchpad

If the microwave runs for a few seconds and stops the touchpad might be at fault. This is not common. Generally speaking, if the microwave display is working and some of the buttons respond correctly but some don't, the problem is with the touchpad.

High Voltage Transformer

If the microwave runs for a few seconds and stops the high voltage transformer might have an intermittent short. This is not common. Check other components related to the microwave symptom first.

Thermostat

If the microwave runs for a few seconds and stops the thermostat might be defective. Watch our video on testing thermostat

Step 3:

Step 4:

Step 5:

Step 6:

use the DVOM tester and fix it. God bless you

see this causes and fix it. God bless you
If the microwave runs for a few seconds and stops the thermostat might be defective. Watch our video on testing thermostats.
If the microwave runs for a few seconds and stops the thermoprotector may have tripped. This is a safety device to prevent the microwave from overheating. It can be tested for continuity to see if it's blown.
If the microwave runs for a few seconds and stops the high voltage transformer might have an intermittent short. This is not common. Check other components related to the microwave symptom first.
If the microwave runs for a few seconds and stops the touchpad might be at fault. This is not common. Generally speaking, if the dishwasher display is working and some of the buttons respond correctly but some don't, the problem is with the touchpad.
If the microwave runs for a few seconds and stops the touchpad and control panel might be defective. There are several other components that can cause this problem, be sure to check any other components before replacing this board.
If the microwave runs for a few seconds and stops there may be a short circuit in the main control board. Check other components first, these boards are often misdiagnosed.
If the microwave runs for a few seconds and then shuts off, a door switch might have failed intermittently. Check each of the door switches for any signs of overheating, arcing, or burning. Also check each of them for continuity. Replace any of the switches that is visibly damaged or that only has continuity intermittently.

I found an envelope with troubleshooting info inside the microwave on the left side behind the front vent. A troubleshooting flowchart was included which indicates that this problem is caused by the high voltage capacitor. I got mine out pretty easy and ordered one from appliancepartspros.com for $55 (which includes expedited shipping. I hope this info helps.

It turned out to be the three door attachments that weren't lined up. It has been fixed. We almost bought a new one because Samsung referred us to a service that would have charged way too much to be worth it even thought the machine is only 3 or so years old. Luckily, we looked further. A local independent appliance fixer came to the house and took care of it within a few hours of my call! Yea!

my panasonic NN-S561 does exactly the same thing