Microwave stopped itself about 3 second after pressing start

A malfunctioning control panel or membrane can cause erratic behavior in your microwave oven. If the control panel is not registering the start command correctly, it may interrupt the cooking cycle. Try cleaning your membrane and control panel with a soft and damp cloth to remove the dust.
If cleaning doesn't resolve this issue, try resetting the microwave oven by unplugging it from the power source for a few minutes, and then plugging it back in.
The microwave may not generate the required heat to cook the food properly if the magnetron or high voltage capacitor is defective. This could lead to the timer counting down without any heating action.

Check that a "favourite" setting has not been selected. The unit may think that is the time that you want to cook. Im not sure about your model but see if there is any clear or cancel buttons to clear any pre programmed selections. If not, unplug the machine for 15 minutes to reset the controller and try it again.

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

Sounds like you have a faulty control panel. I would use a meter and test the power from the control board to the magnetron and circuit board. Chances are the control panel is faulty

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.

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.microwavedisplay.com/safety.txt , http://www.microwavedisplay.com/disassembly.txt and http://www.microwavedisplay.com/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 many Panasonic owner's manuals for free download here.

You can find an authorized Panasonic servicer here.

In Canada, you can find an authorized Panasonic servicer here.

If you're not in the US, see Panasonic.net.

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

The owner's manual is here. On page 10 we find:

COOKING IN ONE STAGE
1. Press the POWER button; the Microwave and High
Cook indicators will light and “PL 10” will light in the
display.
2. Press the POWER button different times to set the
desired power; the display will show the percentage
you chose. If selecting power level 70%-10%, the
Low Cook indicator will light instead of the High
Cook indicator.
3. Press number keys to set the desired cooking time.
OPERATION(CONTINUED)
4. Press the START/+30SEC. button to start cooking;
the Microwave and one of the Cook indicators will
blink and the display will countdown the remaining
cooking time in minutes and seconds. It will beep
five times when cooking is completed.

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://www.microwavedisplay.com/safety.txt , http://www.microwavedisplay.com/disassembly.txt and http://www.microwavedisplay.com/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.

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.microwavedisplay.com/safety.txt , http://www.microwavedisplay.com/disassembly.txt and http://www.microwavedisplay.com/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.

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.microwavedisplay.com/safety.txt and
http://www.microwavedisplay.com/disassembly.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.