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Common Microwave Problems

Have you got a problem with your microwave?  We can help you diagnose what the fault is and give you advice on what to do next.  Please note that microwaves are extremely dangerous appliances, due to a combination of high voltage and high current. It’s recommended that you leave microwave repairs to experienced professionals, even for trivial operations.


My Microwave Is Sparking

If your microwave starts sparking, switch it off and unplug it immediately. It’s possible that there may have been previously unseen incidents of sparking before, and there may be burn spots, so it’s important to get it fixed otherwise a fire might break out.

Basic Checks

Check the microwave for metal fragments that may have crept in – wire wool fragments from cleaning, for example, or even foil from a previous microwave cooking faux pas.

It’s possible that some paint may be chipped, in which case repaint it with microwave-safe paint.

Microwave shelf supports and hangers often come loose and can cause sparking. To prevent this, it’s advisable to use a microwave shelf only when necessary. To fix them, replace the supports and repaint any metal that has become bare with micro-safe paint.

If the waveguide cover is damaged, you will need to replace it. Damage will most likely have been done to the microwave ceiling and walls, so you’ll need to repair this too.

Faulty Magnetron

If sparking is coming from inside one of the side walls of the microwave, the magnetron is likely to be faulty.  Replacing the magnetron should only be carried out by a qualified repair engineer.

Other Causes

Many more minor problems can also cause microwave sparking, for instance burnt-on food or food prepared in certain specific ways (the classic example is a grape cut almost in half, but there are many ways you can create a hazard with food in a microwave). If this is the source of the problem, you might not need to take any action at all.

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My Microwave Won't Heat Up

Problems with no heat from a microwave are most likely to have originated with a defective high voltage diode, high voltage capacitor, faulty door switches, or the magnetron itself.

You should be extremely cautious about removing any covers on a microwave oven without sufficient knowledge of the high voltage system within.

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Why is My Microwave Making a Clicking Sound

It's easy to get used to the convenience of just popping leftovers in the microwave for a quick re-heat. But it can be worrying if your microwave begins to make a strange clicking noise. It's a common problem, with a variety of causes – here are some of the most likely reasons for a clicking microwave.

Magnetron Tube

If your microwave is loud, noisy or making unusual clicking sounds, it could be a result of a defective magnetron tube. The magnetron tube uses high voltage, high current DC power that generates the microwave frequency, which cooks the food, and is meant to be nearly silent.

If it's burnt out or damaged, it can emit a high-pitched, growling or clicking sound. It's not generally dangerous to use the microwave if it starts making these noises. However, it is a warning that the magnetron is on its last legs and needs replacing as soon as possible.

Fan Motor

A noisy or clicking microwave could also be an indication that the stirrer motor has worn out. The stirrer is a metal blade that slowly turns around to deflect microwave energy to a random pattern inside the microwave itself. As it nears the end of its life, it starts to make unusual grinding and clicking noises. Without the stirrer, the microwave won't heat food evenly, so it should be replaced.


A noisy microwave could also be a sign that the turntable motor or turntable rollers are wearing out – a common problem with microwaves, which is easy to replace.

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Why is My Microwave Making a Buzzing Sound

It can be a little worrying to hear a strange buzzing noise, whilst microwaving you dinner, but it's a common problem. Here's how to spot the fault and get your microwave working perfectly again.

High Voltage Component Failure

If your microwave is making a buzzing noise or a loud humming sound, it's likely that a high voltage component has broken or failed – often the magnetron, diode or wave guide.

The magnetron tube emits radiation from the microwave, which heats the food and normally doesn't make any sound at all. A buzzing sound is a good indicator that it's wearing out or already broken.

By Lee Gilbert

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