Microwave Not Heating? Microwave Oven Troubleshooting
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Common solutions for: Microwave not heating
01 - Magnetron
The magnetron uses high voltage, high current DC power to generate the microwave frequency that cooks the food. If the magnetron burns out, the microwave won’t heat. The magnetron is not repairable—if the magnetron is burned out, you must replace it. (Warning: The microwave oven can store a lethal amount of electricity in its high voltage capacitor, even after the microwave oven has been unplugged. Due to the high running voltage and the potential for electric shock, it is extremely dangerous to... replace the electronic components in a microwave. Only a licensed technician should replace the magnetron.)
Highly Likely
02 - Thermal Fuse
The thermal fuse cuts off power to the microwave if the microwave overheats. To determine if the thermal fuse has blown, use a multimeter to test it for continuity. If the fuse doesn’t have continuity, replace it. The thermal fuse cannot be reset—if the fuse is blown, it must be replaced. (Caution: The microwave oven can store thousands of volts of electricity in its high voltage capacitor, even after the microwave oven has been unplugged. Due to the potential for electric shock, it is extremely... dangerous to replace the electronic components in a microwave. Only a licensed technician should replace the thermal fuse.)
Less Common
03 - Main Control Board
The main control board might be defective. However, this is rarely the case. Control boards are often misdiagnosed—before replacing the control board, check all of the more commonly defective parts. If you have determined that all of the other components are working properly, replace the main control board. (Caution: The microwave oven can store thousands of volts of electricity in its high voltage capacitor, even after the microwave oven has been unplugged. Due to the potential for electric sho...ck, it is extremely dangerous to replace the electronic components in a microwave. Only a licensed technician should replace the main control board.)