Microwave Not Heating: 8 Easy Ways To Fix The Problem Now

Microwave ovens are a modern convenience we rely on daily for quick and easy meal preparation. However, when your microwave oven stops heating, it can be frustrating and disrupt your daily routine.

If your microwave oven is not heating your food, it could be due to several reasons, such as a faulty door switch, a malfunctioning magnetron, or a damaged capacitor. These issues can occur over time or suddenly, but the good news is that many can be easily fixed without calling in a professional.

In this article, we’ll review the most common reasons why your microwave may not be heating and ways to fix it easily. By identifying the issue and following the appropriate steps, you can return your microwave to its optimal performance and save money on costly repairs or replacements.

Why is your Microwave Not Heating?

There could be several reasons why a microwave is not heating properly. Some possible causes include the following:

1. Faulty Magnetron

The magnetron is responsible for producing the microwave radiation that heats the food. If it is defective, the microwave cannot heat food properly. A common sign of a broken magnetron is a loud buzzing noise or a burning smell when the microwave is in use.

2. Faulty High Voltage Diode

The high-voltage diode is responsible for converting the power from the transformer into the high voltage the magnetron needs. If it is faulty, the magnetron will not receive the necessary voltage to produce microwave radiation. A sign of a faulty high-voltage diode is a humming sound but no heat production.

3. Faulty Capacitor

The capacitor stores electricity and helps to provide the energy needed to power the magnetron. If it is faulty, the microwave cannot heat food properly. Signs of a defective capacitor include the microwave turning off suddenly or not turning on.

4. Faulty Door Switch

Microwave door switches ensure that the microwave will not turn on when the door is open. The microwave may not heat food properly or turn on if it is faulty. Signs of a defective door switch include the microwave turning on when the door is open or not turning on.

5. Faulty Control Board

The control board is responsible for controlling the various functions of the microwave. If it is faulty, the microwave may not be able to heat food properly or may not work at all. Signs of a faulty control board include the microwave turning on but not heating food properly or displaying error codes.

6. Overheating

Overheating can cause the microwave to shut down and stop heating correctly. This can be caused by various factors, such as cooking food in the oven cavity for too long (prolonged cooking time) or using the microwave too frequently without allowing it to cool down properly.

Signs of overheating include the microwave turning off suddenly during use or not turning on at all.

How to Fix a Microwave Not Heating

If your microwave fails to heat, there are a few step guides you can try to fix the issue:

1. Check the Power Source

Before fixing your microwave, ensure it is appropriately connected to the power source. Check the outlet and the circuit breaker to ensure no electrical problem.

2. Check the Door Switch.

The door or interlock switch ensures the microwave turns on only when the door is closed. If the button is damaged or not functioning correctly, it can prevent the microwave from heating. Use a multimeter to test the continuity of the door switch and replace it if necessary.

3. Inspect the Magnetron

The magnetron is the component that generates the microwaves that heat your food. If it’s not working, your microwave will not heat.

Use a multimeter to check the continuity of the magnetron and replace it if necessary. Keep in mind that replacing a magnetron can be a dangerous task, so it’s recommended to hire a professional.

4. Check the High-voltage Diode.

The high-voltage diode converts the power from the transformer to the magnetron. If it’s damaged, the microwave will not heat.

Check the diode’s continuity with a multimeter by connecting the probes to the diode and replacing it if necessary.

5. Test the Capacitor

The voltage capacitor stores electrical energy used by the magnetron to generate microwaves. If it’s not functioning correctly, the microwave will not heat. Check the continuity of the voltage capacitor using a multimeter and replace it if required.

6. Inspect the Thermal cut-off.

The thermal cut-off is a safety device that turns off the microwave if it overheats. If it’s triggered, it can prevent the microwave from heating. Test the continuity of the thermal cut-off using a multimeter and replace it if required.

7. Check the Control board.

The control board is responsible for controlling all the functions of the microwave. It can prevent the microwave from heating if it’s not working correctly. Inspect the board for any visible damage or loose connections, and replace it if necessary.

8. Call a Professional

If none of the above solutions work, it’s recommended to call a professional for your microwave repair. It’s important to remember that microwaves can be dangerous appliances to work with, so it’s better to be safe than sorry.


How much does it cost to replace a magnetron in a microwave?

On average, the cost of replacing a microwave magnetron falls within the range of $100 to $200. About half of this cost is attributed to labor, meaning you can save money by installing the replacement part independently.

How do I reset my microwave heat?

Resetting the microwave heat settings will depend on your microwave’s specific model and brand. However, here are some general steps that you can follow:

Remove the microwave from the power supply or switch off the circuit breaker that controls it.

Leave the microwave unplugged or turned off for at least 30 seconds to 1 minute to allow any residual electricity to discharge.

Plug the microwave back in or turn on the circuit breaker that controls it.

Check the microwave’s user manual or control panel for a “reset” button or option. Press it to reset the microwave’s settings to their default values.

If your microwave doesn’t have a reset button, you can try pressing and holding the “Stop” or “Clear” button for a few seconds to see if it resets the microwave’s settings.

How do I know if my magnetron is bad?

The magnetron is a critical component of a microwave oven that produces microwaves that heat food. A faulty magnetron may be the culprit if your microwave is not heating. Here are some signs that your magnetron may be bad:

The microwave oven is not heating food evenly or at all.

Strange noises come from the microwave while it operates, such as a buzzing or humming sound.

During usage, the microwave generates sparks  or arcs.

The microwave emits a burning smell or has visible burn marks inside the cooking chamber.

If you experience any of these issues with your microwave, it is best to have it inspected and repaired by a qualified technician. Magnetron replacement is a complex and potentially dangerous process and should only be done by someone with proper training and equipment.

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