If your microwave is making a loud humming noise, first check to see if it still heats efficiently. Often, the humming noise is associated with a microwave malfunction. The following tips will help you troubleshoot the problem in either situation. Replacing your Microwave: (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. Jan 04, 2015 · Hi, Yesterday when turning on my microwave I heard a strange humming noise; louder than the usual noise the microwave makes. It lasted for about 3 seconds and then stopped. Left it on as usual, but everything inside it was still cold. I opened it today and found that a fuse that goes from the...

Nov 30, 2014 · If you allow the inside of a microwave oven to get spattered enough to be fairly described as "disgusting", some of that old food residue is eventually going to char. Charcoal is a pretty effective electrical conductor, and behaves much like the foil in a CD: it arcs and spits and sparks, and whatever is immediately next to it gets really hot ...