Microwave-noise-and-not-heating, a capacitor is an electrical device which stores electricity. a defective capacitor may be why your microwave is not heating but you are hearing a buzzing or humming noise. the capacitor will have to be tested to determine if this is the cause of your problem. a defective capacitor will have to be replaced before your microwave will work again.. 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., over the years i have repaired several microwave ovens. all of them had the same symptom - more noise than usual and no heat. the high voltage circuit of these units is extremely simple comprising a large transformer, capacitor, diode and magnetron..
Microwave runs but does not heat if the microwave runs but is not heating, it could be one of many components. make sure the “timer” function was not inadvertently used. check to ensure the door is closed firmly., my ge microwave suddenly started making a loud humming sound, then it stopped heating food. we unplugged it and plugged it back in, but nothing changed..
When your microwave turns on but does not heat up, it may mean the door switch is broken. the door switch signals other microwave components to supply power when closed, and to stop heating when open. the door switch can also be called an interlock switch., whereas little or no heat produced in your microwave, with an absence of a humming noise is indicative of an open diode. in either case, the diode has to be replaced. with your microwave unplugged, and your capacitor discharged, use extreme caution to remove the lead that leads to the capacitor. you can leave the ground connection attached..
If the microwave does not heat, the humming is likely caused by a malfunction of one of three parts: the power diode, high voltage capacitor, or magnetron. 1) power diode — this is an electronic component that readily passes current in one direction only and blocks the flow of current in the opposing direction.