Why Do Microwaves Stop Working?

We’ve all experienced the frustration of a microwave suddenly stopping working in the middle of heating your food. 

You might have tried unplugging and plugging it back in, but the issue persists. 

Then you are left wondering, “Why do microwaves stop working?”

In this article, we’ll explore some common reasons why microwaves stop working and provide solutions to get yours running again. 

Common Causes of Microwave Failure

There are several common causes of microwave failure, including:

Door switch failure

The door switches in a microwave ensure that the microwave can only operate when the door is securely closed. 

If these switches fail, the microwave may not work at all.

Magnetron failure

The magnetron is part of the microwave that generates the microwaves that cook the food. 

If the magnetron fails, the microwave may not heat or work properly.

High voltage diode failure

The high voltage diode in a microwave converts the AC power from the power source into DC power used by the magnetron. 

If this diode fails, the microwave may not heat properly.

Capacitor failure

The capacitor in a microwave stores the electrical energy the magnetron uses to generate the microwaves. 

If the capacitor fails, the microwave may not work at all.

Fuse failure

The fuse in a microwave is designed to protect the microwave from electrical surges. 

If the fuse blows, the microwave will not work until the fuse is replaced.

Control board failure

The control board controls all of the functions of the microwave, such as the cooking time and power level. 

If it fails, the microwave may not work properly. 


Overuse of the microwave, such as running it for long periods, can cause it to fail prematurely.

Physical damage

Physical damage to the microwave, such as dropping or banging it, can cause internal components to become damaged, thus failing.

Signs of a Failing Microwave

Signs that can indicate a failing microwave include:

  • Unusual noises

If your microwave makes strange noises while running, it could indicate a failing motor.

  • Reduced heating power

If your microwave is taking longer than usual to heat food or is not heating as evenly as it used to, it could be a sign of a failing magnetron.

  • Door issues

If your microwave door doesn’t close properly, it could be a sign of a failing latch, which can be a safety hazard.

  • Sparks or smoke

If you see sparks or smoke coming from your microwave, it could be a sign of a failing electrical component.

 It could also be a sign of food debris buildup inside the microwave.

  • Error messages

If your microwave is displaying error messages, it could be a sign of a failing control board. 

How do you Fix a Microwave that Stopped Working?

Here are some steps you can take to fix a microwave that has stopped working:

  • Check the power source

Make sure the microwave is properly plugged into an outlet and that the outlet is working. 

If the outlet is not working, try plugging the microwave into a different outlet.

  • Check the door switch

The door switch is a safety feature that prevents the microwave from running when the door is open.

You can check the door switch by pressing it. If the switch does not click, it may need to be replaced.

  • Check the fuse

Most microwaves have a fuse that can blow out, which can cause the microwave to stop working. 

Remove the microwave’s outer shell, and check the fuse with a multimeter. If the fuse is blown, you will need to replace it.

  • Check the capacitor

The capacitor stores electrical energy and helps power the magnetron, the part of the microwave that produces the microwaves. 

If the capacitor is faulty, the microwave may not work. 

You can check the capacitor with a multimeter, but having a professional handle it is the best choice.

  • Check the magnetron

The magnetron produces microwaves. 

You can check the magnetron with a multimeter, but like the capacitor, it is a high-voltage component and should be handled by a professional.

If none of these steps resolves the issue, it may be best to consult a professional appliance repair technician to diagnose and fix the problem.

Frequently Asked Questions

How to Extend the Life of a Microwave

Here are some tips on how to extend the life of your microwave:

  • Keep it clean
  • Avoid using harsh chemicals, which can damage the surface.
  • Use microwave-safe containers, for example, glass and ceramic.
  • Don’t run the microwave empty, as it can cause damage to the magnetron, the part that produces the microwaves. 
  • Avoid overheating food: Overheating food can damage the microwave and cause a fire. 
  • Keep the vents clear: Make sure the vents on the microwave are clear of dust and debris
  • Have it serviced regularly by a professional to ensure it’s working correctly and identify any potential problems before they worsen. 

What are Common Problems with Microwaves?

Several common problems that can occur with microwaves include:

  • Microwave won’t turn on

This is often caused by a faulty power cord, a blown fuse, or a malfunctioning control board.

  • Microwave runs but doesn’t heat

If your microwave is running but not heating your food, it could be due to a faulty magnetron, capacitor, or diode.

  • Microwave sparks

If you see sparks inside your microwave, it could be due to a damaged waveguide cover, a metal object inside the microwave, or a faulty diode.

  • The microwave turntable doesn’t turn

If your microwave’s turntable isn’t turning, it could be due to a malfunctioning motor, a broken or worn-out coupler, or a faulty roller guide.

  • Microwave buttons don’t work

If the buttons on your microwave aren’t working, it could be due to a faulty control board or a damaged touchpad.

  • Microwave is noisy

If your microwave is making unusual noises, it could be due to a faulty motor or a malfunctioning fan.

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