THERE WAS APOWER PROBLEM AND MY MICROWAVE COMPLETELY STOPPED WORKING.NO DISPLAY AND NO SIGN OF AN OUTPUT

time for a new microwave?

please follow this steps and fix it. God bless you

1. Main control board If the display on your microwave has gone out completely this is usually a sign that it is a malfunctioned main control board. To correct the issue the main control board would need to be replaced.
   
2. Display board A display board can either malfunction completely or partially, causing two separate results. If the display on the unit has completely gone out, this can be attributed to either a bad main control board or display board. On the other hand, if the display has only partially gone out, this is usually a sign that the display board is defective and 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

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Step 6:

use the DVOM tester and fix it. God bless you

Please post a new help request with brand and full model.

sounds like you blew the fuse inside

Most likely have blown a fuse , get behind the touchpad to ohm the fuse out , replace if blown , if continues to blow check componets for shorts , there will likely be signs of burnt parts.
Phil

when that happen to me i change the bulb and the fuse in of the microwave f the don't work send it to the company that made it and they should tell what wrong.

On my NN-L738BA there is a Child Lock feature.
You set the child lock by pressing the Start button 3 times.
If the Child Lock is enabled it displays the word :CHILD".

To disable this feature on my microwave the manual says to
press the Stop/Reset 3 times.

Check your manual for the Child Lock.

Please reply back with your brand and model number so we can help you.

Is it dead, meaning no lights, no display, no signs of life?

It may have overheated the magnetron and blown the mag's thermal cutout or thermostat.