There may come a time when your microwave will stop working or begins to act strange. It could either stop working completely or parts of it will fail. It can make strange hums and noises, or a noise you used to hear has gone silent. Most of the time, it can come down to the same components failing. Here are five common components that cause problems with microwaves, and their symptoms.

Blown fuse inside the microwave unit:

Blown fuses inside the microwave can cause a variety of issues. The most common issue is that the microwave will completely stop working. Other issues that might indicate a blown fuse include an unresponsive keypad, the microwave starting on its own, and an unresponsive start button.

Defective control board (controller):

Modern microwaves are like mini computers, with their own control boards similar to that of a personal computer. When control boards go bad, keypads and turntables may stop working. Or, the keypads will work, but perform the wrong functions. The clock may also stop working or work erratically. Or, the microwave will turn on at random.

Bad magnetron:

When the magnetron goes bad, the main symptom will be that the microwave will appear to work as normal, but not heat anything. Or, the microwave seems to work at a lower power than usual. This problem can also cause unusual noises, such as a louder than normal hum. In some cases, there may be an unusual burning smell during cooking.

Bad high voltage diode:

Problems with the high voltage diode can also mimic other problems in the microwave such as a bad magnetron. The microwave may make an odd humming sound and heating will be erratic. A technician can go through a series of checks to narrow the problem to the correct component. In some cases, a bad magnetron can directly affect a high voltage diode and both components may need to be replaced.

Bad door switch:

When it is not working correctly, a bad door switch can blow a fuse whenever the door is opened or closed. Bad door switches can also be a cause for the microwave not starting and the touch pad not working. This is because the control board may think the door is open when it is not.

If you suspect your microwave is having problems with any of these components, do not attempt to make a repair yourself. Because symptoms of a bad component can overlap, it's best to have a microwave oven repair technician test each component to determine what the problem is.