3 Reasons Why Microwave will not turn on and lights are off.

If your microwave won’t start and the display is blank and unresponsive, the issue may be with the cylinder in-line fuse. This part protects other microwave components from power fluctuations, and causes a complete loss of power when it fails, meaning your microwave won’t work. If you are aware of the cause of the fuse failure, such as opening or closing the microwave door, you can also test the door switch to see if that is working. If you are unaware of the reason for the fuse failure, you may want to test other microwave parts such as the magnetron, high voltage diode, capacitor, and transformer.

How to test a microwave in-line fuse with a multimeter:

1. Unplug your microwave before starting this test.
2. The fuse will be found near the power cord. Remove the microwave’s cabinet, locate the fuse, and remove it in order to test it for continuity.
3. Set your multimeter to Rx1 and touch the probes to the fuse’s terminals. This test should produce a reading of 0, showing that there is continuity between the terminals.
4. If your test produces a different reading, you will need a replacement fuse.

A problem with the thermal fuse or cut out could be the reason your microwave won’t turn on. The thermal cut-outs, also known as thermal fuses, help keep the oven from overheating. When the thermal cut-outs fail, your microwave won’t turn on as a safety precaution to keep it from getting too hot. Take this opportunity to also check that the cooling fan is working and not causing the microwave to overheat by cutting off airflow.

How to test a microwave thermal fuse with a multimeter:

1. Disconnect your appliance from the power source before attempting this inspection.
2. Locate and remove the thermal fuse. You will need to remove the appliance’s cabinet in order to access it and will need to disconnect the wires attached to the fuse in order to remove it.
3. With the fuse removed from the appliance, set your multimeter to the Rx1 setting, and touch the probes to the terminals to test for continuity. A properly functioning thermal fuse should produce a reading of 0.
4. If the results of your test differ from the above, you will need a replacement thermal fuse.