Microwave Buzzes When Not in Use? 7 Causes & Solutions

Is your microwave making a buzzing noise even when you aren’t using it? Although this issue usually isn’t too serious, it is important to find the cause and prevent any further damage to the unit.

Here’s what might be behind the buzzing noise, as well as what you can do to prevent it.

1. The Cooling Fan

Do you hear the buzzing immediately after turning the microwave off and unplugging it? In that case, you are likely hearing the inner fan that kicks in to cool the machine after you are done with it.

Depending on how hot the microwave gets, this fan might run for anywhere between a few seconds and a few minutes. If it shuts down in this time frame, you have nothing to worry about.

However, if you hear the fan for a lot longer or it starts randomly (without you turning on the device at all) there might be something wrong with the appliance. In the event of that, you should either open up the microwave to look at the fan or take it to a professional.

2. Regular Electric Hum

As with all other electrical appliances, microwaves emit a slight hum even when they’re sitting idly on your counter. Most people either cannot hear this hum or they are able to tune it out and disregard it.

If you can hear the hum and it bothers you, try keeping the device unplugged when not in use. In addition, you can either play some music or invest in a white noise machine. That way, you will be able to effectively tune out the noise and focus on something else.

Now, it goes without saying that this hum is really quiet. So, if your machine is making loud noises, you’re probably dealing with an actual issue. In that case, keep reading to find its cause.

3. Magnetron Issues

The magnetron is an essential part that creates the microwave energy necessary to heat up food. When it’s faulty, the microwave can make buzzing or rattling sounds. In addition, the noise usually gets louder the higher the temperature becomes.

To check whether the magnetron is causing the noise, try running the microwave at a lower temperature for longer time intervals. In case the noise is quieter or entirely gone, the magnetron is indeed the problem.

Before you opt for a replacement, it is essential to consider your budget. Namely, a magnetron replacement can cost anywhere between $100 and $200. The price is reduced a little if you replace it on your own, but you’ll need some special equipment for it.

So, you should ask yourself whether a replacement is truly worth the expense. For the same money, you could get a brand-new microwave and put the entire thing behind you for good.

4. A Defective Motor

Your microwave could also buzz without being on due to a faulty motor. This issue is especially common with older devices that have already gone through repairs or upgrades.

If you suspect the motor is the issue, taking the oven to a professional is the best course of action. They can inspect it and give you an estimate, after which you can decide whether repairing the motor is a worthwhile investment.

5. Loose Parts

Is the buzzing also accompanied by clicking and rattling? In that case, you’re likely dealing with loose mechanical parts. Bolts and screws are usual culprits, especially those on the motor.

To assess and solve this problem, you can open the device and take a look at its insides. If you notice that anything is loose, tighten it, and make sure it is 100% secure. When you turn the microwave back on, the noise should be gone.

6. A Faulty Control Panel

A malfunctioning control panel can cause all types of noise, ranging from buzzing to rumbling. Unless you are truly well-versed in microwaves, you will likely have to take your oven to an electrician or mechanic. In most cases, though, this issue is easy to resolve and the microwave is as good as new.

7. Defective Bearings

Last but not least, you should also check on the microwave’s bearings. They can bend due to excessive heat, causing them to make buzzing and thumping noises even when the machine is off.

Fortunately, bearings are pretty inexpensive to replace, and you can do it on your own. Just check the specifications for your unit so you can get the right type, and you’ll be good to go.

Summing Up

If you hear a buzzing sound from your microwave even when it’s off, you should check it for any defective parts. In most cases, the noise comes from the engine, loose parts, or defective bearings.

To ensure your microwave lasts you a long time, it’s essential to do regular maintenance on it. That way, you’ll prevent most problems from occurring, and the device will not make any annoying sounds when on or off.

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