Your Microwave Oven Is Noisy

Have you noticed your microwave becoming noisier recently? Here we explain why your appliance is making this strange or abnormal humming or buzzing sound. There are several things that might be causing this issue.

THE POTENTIAL CAUSES FOR THIS ISSUE:

• The turntable is damaged

• The turntable motor is faulty

• The cooling fan is vibrating

• The high voltage diode has failed

• The capacitor is defective

• The magnetron is faulty

WARNING
We recommend adopting a very cautious and safety-conscious approach if you need to take your microwave apart at any point.
Microwave ovens produce powerful electrical discharges that can potentially be fatal.
Never test and use a multimeter on the appliance with it still plugged into the mains. The voltages on either the magnetron, transformer or capacitor may be too high for the multimeter to cope with.
Even when unplugged, the capacitor inside the microwave oven can still produce power electrical discharges.
We therefore recommend you leave the appliance to discharge for at least one day before taking it apart.
When you first open the microwave up, make sure you short circuit the capacitor using a pair of electrically insulated pliers (with the appliance unplugged from the mains of course).
We also recommend wearing a pair of electrically insulated gloves to ensure you are able to work in complete safety.
Carrying out repairs on a microwave oven requires a very careful and safety conscious approach. SOS Accessoire cannot be held responsible for any accidents that may occur.

The turntable is damaged

The turntable provides the surface on which you actually place your food in the microwave. If you can hear a grating or squeaking noise, check the drive coupling that supports the turntable. This kind of problem is often caused by this coupling getting fouled up with dirt and grime, or simply breaking. If this is the case, it will need to be replaced.

The turntable motor is faulty

The turntable motor enables the turntable to rotate, ensuring your food is cooked uniformly. If the motor is faulty, the microwaves will not be evenly distributed, and you'll also hear a grinding or squeaking sound. You can check the motor using a multimeter in voltmeter mode. First find where the motor is located underneath the appliance. Next, place the multimeter's two probes on the motor's terminals to check that it's definitely being supplied with 230 volts. If the motor refuses to operate, you will need to replace it. Before doing any of this, however, carefully read the safety instructions at the beginning of this troubleshooting guide!

Buy a microwave turntable motor

The cooling fan is vibrating

The cooling fan prevents your microwave from overheating. It sits inside the outer casing and works by cooling the magnetron. With use, it can become worn and loose, causing it to generate a lot of noise. It this is the case, it will need to be replaced.

The high voltage diode has failed

The high voltage diode enables the magnetron to function properly. If you hear a dull sound, and this is followed by the microwave stopping working, this may be a fault with the diode. You can check it using a multimeter in ohmmeter mode. Open up your microwave's outer casing and locate the diode: it will be connected to the capacitor at one end and to your microwave's chassis ground at the other. To test it, first make sure you've carefully read the safety instructions provided at the beginning of this troubleshooting guide. Next, disconnect the diode's connectors and place the multimeter's two probes on its terminals. If there is continuity, this means the diode is no longer working and will need to be changed.

Buy a microwave diode

The capacitor is defective

The capacitor is fed with the 2,200 volts from the transformer and redistributes this voltage to the magnetron. If the capacitor is defective, we advise you to stop using your appliance until it's repaired. Do not under any circumstances attempt to check and test the capacitor: the multimeter will not be able to cope with it, and there is a risk you could get electrocuted. Carefully follow the safety instructions provided at all times.

The magnetron is faulty

If the magnetron develops a fault, the microwave will no longer be able to heat your food properly. The magnetron will also become noisy and probably blow the appliance's fuse. To diagnose the problem, you need to test the magnetron's resistance using a measuring device. Important: remember to follow the safety instructions provided at the beginning of this troubleshooting guide. Before carrying out this test, check your multimeter is definitely set to "Ohms Ω". To take the measurement, first disconnect the magnetron's connectors, then place the multimeter's probes on its terminals. If the value you obtain is around zero, the magnetron is working correctly and is not the source of the fault. If you obtain a null value (the multimeter does not react at all), this means the magnetron is no longer working and will need to be replaced. The cause of the issue may also be an insulation fault: place your multimeter's probes on the magnetron's terminals and its outer body; if a value is displayed, the magnetron will need to be replaced. Do not under any circumstances attempt to test your appliance with it still plugged into the mains: there is a risk you could get electrocuted.