Why Does My Microwave Make Noise?

Jul 29, 2023, 12:49pm

The microwave can make several noises:

  • a rubbing noise,
  • vibration,
  • a whistle
  • or even an audible signal during a program, such as in convection.

If it emits a light hissing noise (electric) or a shrill sound signal, then it is the electronic card which is in question and which will have to be changed. It is located behind the control panel.

Otherwise, you have to go through these different parts until you find the source of the noise. To do this, you will need to check several elements:

  • the turntable
  • the roller stand
  • the fan
  • the magnetron
  • the transformer

The hum of a microwave in operation is a familiar sound in many kitchens. However, when your microwave starts making unusual noises, it can be cause for concern. Understanding the source of these noises can help you determine whether it’s a minor issue or something that needs immediate attention. Let’s explore the common reasons why a microwave might make noise.

Why Does My Microwave Make Noise?

Normal Operating Noise

First, it’s essential to distinguish between normal operating noise and abnormal noise. A soft humming sound when the microwave is running is perfectly normal. It’s caused by the magnetron, which generates the microwaves that heat your food. Also, the turntable motor, which rotates the food for even cooking, may create a low humming or clicking sound.

Loud Buzzing or Humming

If your microwave is emitting a louder humming or buzzing noise, it could indicate a problem with the magnetron or the high-voltage diode, which works with the magnetron to heat the food.


A malfunctioning magnetron or high-voltage diode needs professional attention. Due to the high voltage present in these components, it’s not safe to try to repair them yourself. If these parts are defective, a professional repair or replacement is required.

Grinding or Screeching Noise

A grinding or screeching noise is often due to a problem with the motor that rotates the turntable. If the motor is damaged or worn out, it can start making unusual noises.


If you suspect the motor is the issue, you should consult with a professional appliance repair service. The motor will likely need to be replaced.

Rattling or Knocking Noise

A rattling or knocking noise often comes from a loose or broken part inside the microwave, such as a stirrer, a fan blade, or the turntable mechanism.


You’ll need to identify the loose or broken part causing the noise. If it’s the turntable, for example, you might need a new drive motor or roller guide. However, if the noise comes from the stirrer or fan, it’s best to seek professional assistance as accessing these components can be tricky and potentially dangerous.

Popping Noise

Popping sounds often come from the food being microwaved, but if you hear popping noises when the microwave is empty or the noise is exceptionally loud, it might be due to a problem with the capacitor or the magnetron.


Both these components are high-voltage and dealing with them can be hazardous. If you suspect these parts are causing the issue, you should seek professional help.


Various parts may cause abnormal noise such as rubbing, humming, vibration. It can be a turntable or a roller stand.

  • Turn on the microwave by removing the baking sheet and its support. To prevent the microwave oven from running empty, put a glass of water inside for testing.
  • If the noise disappears after removing the support and glass cover, then they are responsible:
  • Pay attention to the glass tray: it may be deformed, broken, cracked or in poor condition.
  • Inspect the roller stand, if it is in poor condition, replace it.


Before any intervention in the microwave oven, the parasitic filter and capacitor must be discharged.

To discharge the noise filter: Using an insulated screwdriver (or pliers), tap

  • two plugs of the socket of your device (phase – neutral),
  • then a plug and a hole in the center (phase – earth)
  • and finally another plug and center hole (neutral-to-ground).

To discharge the capacitor

  • Loosen the fixing screws and remove the cover of the device.
  • Using insulated pliers, connect the two terminals of the capacitor to create a short circuit. There may be a spark, which means the capacitor is discharged.

Why Does My Microwave Make Noise?


The fan is designed to cool the system and is located behind the magnetron, at the back of the microwave.

It is possible that this one is in poor condition, thus causing noise. He can:

  • rub against another piece
  • propeller broke


After discharging the capacitor, check the condition of the magnetron.

Start the heating program, which you will stop after a few seconds. It shouldn’t work well with empty microwaves, but there’s no danger here, because the magnetron is off, there won’t be a wave.

If the noise goes away, the magnetron was the cause of the problem.


It will be necessary to check the condition of the transformer.

  • Disconnect the left side of the transformer, which is called the “primary”. This is the transformer power supply.
  • Plug the device back in and run the program, then turn it off after a few seconds, just to see if the noise persists.
  • If the noise disappears, then the transformer is faulty. Therefore, it needs to be changed.

To check this, observe the state of the blades and rotate them to see if they are touching another part. If it is in poor condition, replace it.

In conclusion, while some noise is normal when your microwave is in operation, unusual noises can signal a problem. If you cannot identify or solve the issue yourself, always seek the help of a professional appliance repair technician. Regular maintenance and care can prolong the lifespan of your microwave and keep it running smoothly.