Microwave Oven Problems

Microwave ovens last for a long time and you can expect to get around 10 years of use out of them before you consider getting a new one. When you get to that point, there may be some issues with your oven as a result of old age.

In this article, we’ll be looking at some of the most common problems you will face with a microwave and how to remedy them. Bear in mind that microwave ovens are a relatively inexpensive cooking appliance and if your microwave oven is faulty, it may be cheaper, quicker and easier to just replace it with a new one.

Faults, Fixes and Help with Microwave Oven Issues

Why is my microwave not heating up?

There are likely to be three possible reasons why your microwave isn’t heating up:

  • One potential reason for your microwave oven not heating up are the door switches. Your microwave door will have up to four door switches. These activate in a sequence when the door is shut to ensure that it is properly closed. You will need to test your microwave oven using a multimeter to see if one of the door switches is faulty. If it is, you should replace it. Please note that any electrical work should be carried out by a professional as even with the oven unplugged, there is still a potential that you can shock yourself when tinkering with the electrical components of a microwave oven.
  • Another possible cause is the oven’s magnetron which generates the actual microwaves that cook the food. If this has burned out, you can’t replace it. You will need to replace the microwave oven.
  • Perhaps the most likely cause is that the diode, which increases the voltage to the magnetron, has burned out. If this is the case, then the magnetron can’t receive enough power to generate microwaves. If a diode is burned out, you should be able to tell by looking at it, so just identify it and inspect it. If you can’t tell by looking at it, you can test it with a multimeter.

Can you overheat a microwave?

It is possible for a microwave to overheat. The microwaves heat food by targeting water molecules, if there is no moisture in the food to heat, this can cause overheating. The vast majority of them have an automatic shutdown feature if they do, though. It’s very unlikely that your microwave will overheat, but if you are cooking something for a long time, there’s a chance it will.

Another reason it may overheat is because of a faulty fan. You can hear the fan whenever the microwave is cooking, so you should be able to tell almost straight away if there is something wrong with it. Without the fan to regulate the temperature, the microwave will overheat quickly and shutdown.

Why is my microwave sparking?

If your microwave is sparking, do not panic. Just switch it off at the wall, and then inspect it. There are three main things to look out for if your microwave is sparking:

  • If there is any metal debris inside of the microwave, this could well be the cause. Metal reflects the microwaves and causes sparking. This is why you should never put food tins or tin foil in your microwave. It could be something like a strand of steel wool that has found its way in there. Ensure there is no loose metal in the microwave and you have a microwave-safe dish to heat your food in.
  • One of the parts of a microwave is the rack support. This is a small hook-shaped component. If the paint has worn out on it, this could cause the sparking. If this is the case, you’ll need to replace it.
  • Check the wave guide cover. This is a small grill found inside the microwave that lives up to its name by guiding the microwaves to the food. It also protects the magnetron from debris. Food particles can get stuck on the wave guide during cooking. The microwave oven will then burn these bits of food, resulting in sparks. You should clean it or if your wave guide cover is damaged, you should seek to replace it.

If none of these explain why your microwave is sparking, you should consider calling a technician or replacing the unit.

What do you do if your microwave catches on fire?

If your microwave oven catches on fire, you need to act quickly and calmly. If it is safe to do so, turn off the microwave oven and unplug it immediately. If there is a fire burning inside the unit, do not open the door to try and extinguish it. This simply opens up the possibility of the fire spreading elsewhere. Wait for the fire to suffocate inside the oven before you think about opening the door.

Don’t take your chances, either. Alert the authorities if there is any risk of the fire spreading. You can prevent this ever occurring by:

  • Following the safety instructions provided by the manufacturer.
  • Only heating food items that are approved for microwaves.
  • Never heat any metal items in microwaves, of any kind.
  • Clean your microwave regularly.
  • Follow cooking instructions on the packaging when heating food items.

Why does my food spark in the microwave?

It is possible for your food to cause sparks in your microwave oven, this is most commonly seen in dense vegetables. Their higher content of minerals can cause sparks to fly. Your food may display small signs of burning but should overall avoid damage and still be safe to eat.

It is most commonly seen with carrots, spinach, bell peppers, green beans and other dense vegetables. The sparking is a result of the microwaves reflecting off of the minerals found within the food. It’s still safe to eat, but the sparking may cause your food to not be as heated as you may have hoped.

Why do my microwave buttons not work?

There are three potential areas of the microwave that would explain the controls of it not working:

  • The control panel
  • The membrane switch
  • The control board

If some of the buttons on your control panel work and others don’t, then the problem most likely lies with the control panel itself and it will most likely need replacing.

If this doesn’t explain it, it could be the membrane switch. It has a conductive layer around it which can become faulty after a while of usage. To check for this issue, you will need to ensure it is unplugged and remove the cabinet of the microwave. Using a multimeter, check the membrane switch. It should give you some ohms of resistance. If not, it needs replacing.

If the touch controls of your microwave are unresponsive but the display lights are still working as usual, it is most likely the problem is with the control board. The control board provides power for the membrane switch. Without it, your oven buttons won’t work. This is a complicated component to replace and is best left to outside help.

We must reiterate that unless you are confident you know what you are doing, you should seek professional help when conducting repair work on your microwave oven. Even if you unplug the unit, thousands of volts can be stored inside and cause a seriously harmful shock if you don’t know what you’re doing. Avoid tinkering with the electrical components of the unit at all costs.

Why does my microwave plate not spin?

This is another problem that has a few different possible explanations;

  • The first thing to check is the roller guide. This is usually a three-pronged item that sits under the microwave plate. There are small wheels at the end of each prong. Take that out and check it for damage and that it’s still working. If it’s damaged, replace it.
  • If the roller guide has no problems, it’s time to check the drive motor. By removing the bottom panel of the microwave, you can access the drive motor. If it doesn’t rotate or makes a peculiar grinding noise, it needs to be replaced. If it isn’t making a noise and there doesn’t look to be visible signs of damage, test it for continuity using a multi meter. We recommend the help of a professional if this is the case.
  • If neither of those are providing answers, you should check the drive coupler. You’ll also find it under the bottom panel of the microwave, attached to the motor shaft. Take off the coupler and check it for damage. Replace this if it is.

Hopefully this has addressed any problems you may be having with your microwave oven. They generally run very well and you’re not likely to run into many problems with your microwave. You can expect your microwave to show these signs of wear and tear after around 10 years of use. If there is a problem with the electrical components of the unit, leave it to a professional unless you’re absolutely confident you know what you’re doing.

To shop from our expansive range of microwave ovens, head over to our cooking section. There, you’ll also find state-of-the-art range cookers, built in ovens and hobs if you want to give your kitchen an upgrade.