How to Repair Microwave Oven Not Heating

If you’ve noticed your microwave oven is no longer heating up the way it used to, then you may be wondering what could be causing the problem. While some people might automatically turn to professional help when looking for a solution to appliance issues such as this one, repairing your own microwave oven can actually be quite simple and quick if done correctly.

How to Repair Microwave Oven Not Heating

In this blog post, we’ll walk you through the steps on how to repair microwave oven not heating so that you can get back to using it in no time! So grab your tools, and let’s get started!

Why Is My Microwave Running but Not Heating?

If your microwave runs but isn’t heating, the problem could be caused by a few issues. Before any major repairs are done, it is important to check and troubleshoot some of the more common issues. This will help narrow down what may be causing the lack of heating in the microwave oven.

First, make sure that your appliance is receiving power. Check if the outlet works for other appliances or if a circuit breaker has been tripped. If there is no power coming through, resetting or replacing the fuse can solve this issue.

Another possibility could be an issue with the door switch. If you open and close the door while running a test cycle (2 minutes on high) and notice that nothing happens, the problem could be a faulty door switch. This can be checked by testing it with a multimeter or having your local appliance repair technician check it for you.

It is also possible that the problem could be with the magnetron or high-voltage diode in your microwave oven. If either of these components stops working correctly, they will need to be replaced by an experienced repair specialist.

Finally, if your appliance is still not heating after trying all the above solutions, then it may be time to replace the entire unit so that you don’t have any further problems down the line. This is usually only necessary when other repair attempts have failed and/or when parts are no longer available for replacement.

10 Methods How to Repair Microwave Oven Not Heating

1. Check the Power Supply

One of the first things you should do if your microwave oven is not heating is to check the power supply. Make sure that the microwave is plugged into an outlet and that the outlet is working. You can also try plugging the microwave into a different outlet to see if that makes a difference. If you have a power strip or surge protector, make sure it is still working and hasn’t been tripped.

Check the Power Supply

Another option is to check the circuit breaker and reset it if necessary. If all of these steps fail, it is possible that the microwave may be getting power but not enough to heat due to a faulty element. Although this can be difficult to diagnose and repair, it may be necessary to contact a professional.

2. Check for Blown Fuses

If your microwave oven has blown fuses, it will not be able to generate enough heat to cook food properly. To check for blown fuses, you will need to remove the back panel of the oven and inspect both fuse holders for signs of damage or corrosion. If either of these is damaged, they will need to be repaired or replaced before proceeding further.

If the fuses appear to be intact, the next step is to test them with a multimeter. This is done by placing the meter’s probes on both ends of the fuse. If the multimeter does not measure a closed circuit, then the fuse has likely blown and should be replaced. Fuses can be purchased at any hardware store or online retailer.

3. Check the Door Seal

Another potential issue that could cause your microwave to stop heating food is a faulty door seal. Over time, door seals can become worn or damaged, which can allow heat to escape from the oven. To check the door seal, put a piece of paper inside the oven and close the door. If you can pull the paper out easily, then there may be an issue with the door seal.

If there is an issue, you’ll need to replace the seal. If you don’t feel comfortable doing this, call a professional repairman to have it fixed safely and efficiently. While you’re at it, you can also check the waves and sparks inside your oven. If they are not functioning properly, then it may be time to replace your microwave.

4. Clean the Interior

If your microwave has been used frequently, there may be food or grease build-up inside the oven that is preventing it from heating properly. To clean the interior of your microwave, mix equal parts water and vinegar in a bowl and put it inside the oven on high power for five minutes. Then, use a cloth or sponge to wipe down the inside of the oven.

Clean the Interior of Your Microwave

If there is any stubborn grease, you can use baking soda or a specialized cleaner to remove it. Once the interior has been cleaned, try re-heating the food in the oven and see if it is now heating. To prevent future build-up, make sure to clean any spills or splatters after use.

5. Replace any Worn Parts

Over time, certain parts of your microwave may become worn out and need to be replaced in order for it to continue working properly. Common parts that may need to be replaced include light bulbs, filters, and turntables. If you are not sure how to replace these parts yourself, you can always contact a professional for help.

Although replacing these parts can be costly, it may be worth it in the long run if it means avoiding more serious problems. Additionally, you should always double-check to make sure the parts you are buying are compatible with your specific model of the microwave oven.

6. Calibrate your Oven

If your microwave seems to be cooking food unevenly, it may need to be calibrated. To calibrate your oven, simply follow the instructions in your owner’s manual. This process usually involves setting cook times and power levels for specific types of food so that your oven knows how to cook them properly.

Once your oven has been calibrated, it should be able to cook food evenly. Additionally, calibrating your oven helps conserve energy and prevents wasting power. If you are having trouble calibrating your oven, contact a professional to help. However, if the calibration does not help to fix the issue, you may need to replace the magnetron.

7. Check the Magnetron

The magnetron is responsible for generating microwaves that heat food. If it is defective, the oven will not heat properly. To test the magnetron, you will need to use a multimeter to measure the resistance of the coil. If the resistance is not within specification, the magnetron will need to be replaced.

Magnetron is Responsible
for Generating Microwaves

Be sure to unplug the oven before attempting to remove or test the magnetron. Try to locate a replacement magnetron that is exactly the same as the one you are removing. It must have the same wattage and voltage rating. Make sure the new one is installed securely and that all its connections are properly secured.

8. Check the Diode

The diode converts AC current into DC current and is an important part of the microwave oven’s electrical system. If it is defective, the oven will not heat properly. To test the diode, you will need to use a multimeter to measure the forward and reverse bias voltage of the diode.

If either of these readings is outside of specification, the diode will need to be replaced. Once the diode is replaced, your microwave should be heating properly. When replacing the diode, be sure to follow the manufacturer’s instructions and use a diode of the same rating.

9. Check for Proper Ventilation 

Microwave ovens require proper ventilation in order to function correctly. If there is something blocking the vents, such as grease or dirt, it could cause problems with heating. To clean the vents, you can use a vacuum cleaner with a soft brush attachment to remove any debris that may be blocking them. If there is an accumulation of grease or dirt, you may need to use a cleaning solution to remove it.

10. Check for Loose Connections 

Loose connections are another common reason why microwave ovens stop heating properly. To check for loose connections, you will need to remove the back panel of the oven and inspect all of the wires and terminals for signs of damage or corrosion.

 Check for Loose Connections

If any of these are damaged, they will need to be repaired or replaced before proceeding further. If the connections are intact, then make sure that all of them are firmly connected to their respective terminals. Once this is done, turn on the oven and see if it starts heating again. If not, then you may need to move on to the next troubleshooting step.


Now that you know how to repair microwave oven not heating, it’s time for you to get started and make any necessary repairs! With the help of these tips and tricks, you can confidently diagnose and fix the problem in no time at all. Remember that if you feel uncomfortable making the repairs yourself, always consult a professional or have them do it for you.

That way, you can be sure any problems are addressed correctly the first time around. So now that you know how to repair a microwave oven not heating, why wait? Let’s get those repairs underway so your kitchen can work properly again!

Angela Ervin

Angela Ervin

Angela is the executive editor of DIY quickly. She began her career as an interior designer before applying her strategic and creative passion to lifestyle and home. She has close to 15 years of experience in creative writing and online content strategy for housekeeping, home decorations as well as other niche efforts. She loves her job and has the privilege of working with an extraordinary team. She lives with her husband, two sons, and daughter in Petersburg. When she's not busy working she spent time with her family.

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