We always encourage the do-it-yourselfer to plunge in, but there are some things better left to the pros. Your microwave is a case in point.
First, you can — and should — keep the interior and the inside of the door clean. Microwaves don’t distinguish between spills and food and cook them all. Each time you cook, the microwaves blast the food deposits, eventually turning them into carbon. This reaches such high temperatures, it can damage or destroy the unit’s enamel, plastic and glass components.
You can also replace the light bulb, as long as you don’t need to remove the entire case. Unplug the microwave, remove the small cover over the bulb, and replace it.
And you can check for leaking microwaves with an inexpensive tester.
And that’s where you should stop. You might think a simple fuse replacement is easy, but there are two reasons you should not do this on your own.
A microwave is a combination of mechanical and electronic components. The fuse itself is a simple mechanical device, which is easily replaced. But microwaves also have something called a monitor switch, an electronic fail-safe system that ensures, among other things, the oven won’t run when the door’s open. When the fuse blows, this switch may have shorted. It’s too small to see, and manufacturers say it must be replaced every time the fuse blows.
Actually, you should never remove the unit’s cover. Why? A little cylinder called the capacitor. Even unplugged, the capacitor stores something like 2000 volts. This is enough to kill you. With that kind of voltage, you don’t even need to touch a terminal to jump the spark. Repair professionals discharge the capacitor by shorting two terminals or shorting to ground, but unless you’re very confident with electricity, better to stay away.