Microwave Troubleshooting: Common Problems and How to Fix Them

November 2, 2022
Microwave Repair

A microwave is one of the most commonly used appliances in the modern kitchen and it’s frustrating when it isn’t working correctly. This handy guide will help you troubleshoot the most common microwave problems and walk you through how to fix them. 

1. Microwave not Turning On

Once you have made sure that your microwave is correctly plugged into the power, you will need to try to diagnose why your microwave is not running. Here are some tests you can perform:

Check that the electrical outlet is working

You can use a multimeter to ensure that the electrical outlet the microwave is plugged into has electricity. If you don’t have a multimeter, you can try plugging a different appliance into the same outlet. If the issue is determined to be with the outlet, you will need to get this repaired by an electrician in order to solve the problem. 

Check that the door latch is working properly

Microwaves have an inbuilt safety feature which means they won’t run if the door is not properly closed. This means that if something is wrong with the door latch mechanism, the microwave will not run, even if it appears to be closed. If you determine the door latch is faulty, you will need to replace the part.

Check the fuses

A microwave has two fuses, a ceramic fuse and a thermal fuse. If either of these are faulty, your microwave will not run. You can use a multimeter to test these fuses. If either are not working you will need to order a replacement part from the manufacturer.

2. Light not Working

If your microwave light is not working, it is usually an easy fix that can be solved with a replacement bulb. Check your user manual to find what sort of bulb your microwave needs and order a replacement. Once you have the new bulb, remove the old one and replace it, then test to see if the light works again. 

3. Plate Not Turning

First, check to make sure that the plate is correctly positioned on the roller guide and that there is no food or debris lodged in the mechanism. You should also check to make sure the roller guide itself is not damaged. If everything looks normal but the plate is still not spinning, then you will need to try replacing the motor. To do this:

  • First, order a replacement drive motor from your microwave manufacturer
  • Once you have the replacement part, ensure that the microwave is disconnected from the power supply.
  • Put the new motor in its place, then test to see if the microwave plate is now spinning. 

4. Door Not Closing Properly

It’s typical for the door to stop shutting properly over time on older microwaves. This frequently occurs as a result of the hinges or springs losing their tightness. 

Heat and odors may escape the microwave when the door isn’t properly closed, and a door that won’t latch on a microwave may be challenging to open or close.

Check the door latch system, the hinges, and any associated torsion springs. Replace any damaged parts and tighten any loosened screws. Replacement parts can be ordered online from the manufacturer. 

5. Door Not Opening

This problem most often occurs with microwaves that have a push-release door switch. 

Check your user manual for the manual override for your individual microwave make and model – the majority of microwaves include one. Once the door is open, examine the latch assembly for any signs of deterioration. If the latch appears to be fine, you will need to replace the release button mechanism. This can be ordered online from the manufacturer. 

6. Microwave Running But Not Producing Heat

A common problem, especially with older microwaves, is that they will turn on, light up and make a humming noise, but not produce any heat. If this happens, the first thing to check is the door latch mechanism, as this can affect most aspects of a microwave’s performance. 

If the door latch is intact, you can use a multimeter to test both the voltage diode and the magnetron. If either one has an issue, you can replace them. As this issue usually only occurs in older microwaves, you might find it is more cost effective to purchase a new microwave rather than spend money buying replacement parts for an older model. 

7. Microwave Making Loud Noise

A noisy microwave is most often caused by an issue with the plate drive mechanism. As outlined above, check to ensure that the roller guide is free from obstruction and the plate is positioned correctly. If these are all fine, you can try replacing the drive motor.

A faulty cooling fan can also be the cause of the noise. Check to make sure the cooling fan is unobstructed and remove any obstructions if you find them. If the fan is bent or damaged in some way, you will need to order a replacement. If the fan is unobstructed, undamaged, and spins freely, it will not be the cause of the noise.

Other parts that may be to blame for a noisy microwave are the voltage diode and the magnetron, but as these parts are difficult to replace you may find it is more effective to just replace the microwave. 

8. Microwave Touchpad Not Working

If your touchpad is not working, checking the membrane switch is the best place to start because it will tell you which buttons don’t work. If several buttons fail to function, you will most likely need to replace the entire touchpad unit. You can order a replacement part from your microwave manufacturer.

If the buttons work, check the main control board – if it is faulty, you are probably better off buying a new microwave than replacing it, as it is a time-consuming and expensive repair.


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