Microwave is one of the most commonly used electronic appliances these days. Most people, no matter what the location own a microwave for cooking and heating purposes. Microwaves are easy to use, take less space and fulfil several purposes. However due to their constant usage, they may start showing certain faults from time to time. For example, it may stop heating and there could be many reasons or causes for this. If your microwave is not heating, then you can go through the following given probable causes and solutions.
1. High voltage diode problem
The most common reason for microwave not heating could be problem with high voltage diode. High voltage diode helps to power the magnetron and is located in the cabinet. To check whether this is really the issue and to solve it, you need to unplug the microwave and then discharge the high voltage capacitor. Use a multi meter in order to test the diode. There must be low resistance in one direction and high in the other. If not then the diode may need to be replaced. However if the diode is fine then the issue may be related to the high voltage circuit.
Some of Diodes available online:-
2. Problem with the door switch
Another possible cause when microwave is not heating is an issue with the door switch. The door switch is also known as the interlock switch and it can be accessed by removing the cabinet. For this first unplug the microwave and then test using a multi meter. Depress the actuator button and check the switches. If you find no continuity at this point then you may need to replace the switch. Also when testing this, you must ensure that the door hooks as this triggers door switch are working correctly.
Here are some of the recommended microwave door switches:
3. Problem with the magnetron
If your microwave is not heating, then the problem could also be with the magnetron. Magnetron is an important part of the microwave and is responsible for providing the heat which cooks the food. In case the magnetron is broken then this may lead to blowing up of the fuse which could further result in other components failing. To check the magnetron, unplug the microwave and then remove the cabinet. After this, discharge the high voltage capacitor and test. While testing the magnetron, disconnect the attached wires and attach the leads of the multi meter to the terminals of the magnetron. The continuity that you get should be about 2-3 ohms of resistance between the terminals as well as the grounded outer case. If this is normal then the problem could be something else.
Some commonly used Magnetrons available online:-
- GE Microwave Oven Magnetron and Diode Kit OM75P
- LG Electronics 6324W1A001H Microwave Oven Magnetro
- BlueCatELE 2M246 Microwave Magnetron Tube
- Supplying Demand SD0259 Microwave Magnetron Compatible AP5183463 & Fits 0M75
- Generic Microwave Magnetron Tube WB27X10516 OM75P(31) Air Cooling Compatible for GE Samsung

Image Credits: Wikimedia Commons
Now that you know the possible causes of microwave not heating, you must contact a technician to get the problem resolved or the parts replaced. There are many technicians or professionals out there who are experienced with repairing microwaves and one can be contacted by reaching out to Mr Right in case of microwave not heating.
If you are a DIY person, here are some recommended tools and equipment for you:-
Multi-purpose Multimeters :-
Multi-purpose Tool Kit:-
- DEKOPRO 168 Piece Hand Tool Kit with Plastic Toolbox Storage Case
- Dedeo Cordless Hammer Drill Tool Kit, 60Pcs Household Power Tools Drill Set with 16.8V Lithium Driver Claw Hammer Wrenches Pliers DIY Accessories Tool Kit
- BLACK+DECKER 12V MAX Drill & Home Tool Kit, 60-Piece (BDCDD12PK)
- WORKPRO 156-Piece Home Repair Tool Set – Daily Use Hand Tool Kit with Tool Bag
Soldering Kits:-
- A-BFastiron Electronics Soldering Iron Kit, Welding Tool for electronic repairs and DIY
- Soldering Iron Station Solder Kit – 48W 110V Soldering Tool Set Temp Adjustable Electric Welding for SMD/PCD/DIY
- Soldering Station With Additional 5 Tips
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Our microwave is making too much noise when it is in use. I’ll make sure to mention this to my father. This is very helpful.
Thank you for the tips. I’ve been looking for microwave oven problems for 2 days now. I’ll make sure to check each items you have listed and immediately contact a professional to get it checked out.
Can the Megnetron be replaced? Is it worth it to do so?
Repair person in Minneapolis MN and cost?
Thank you,
Katherine Eckstrom