Why Is Microwave Making Popping Noise – How To Fix

If you want to enjoy fast and hassle-free cooking, the microwave is the most essential appliance you need for your kitchen. But if the microwave starts malfunctioning and making noises, it will raise your concern.

Sometimes, the microwave popping sound is also an issue that will leave you wondering whether your appliance is functioning properly or not. Regarding this, it creates a humming sound when it starts processing cooking which is normal unless it’s too loud.

Just so you know, the popping, crackling, and similar sounds are mostly normal because the food gets rapidly heated and makes these sounds. Especially when you cook dishes with high fat, but the microwave making popping noise becomes a bit too intense.

However, constant odd sounds from your microwave can stipulate that there are some underlying problems. Further, popping sounds can occur if you spray cooking oils in the microwave, which is not a good idea.

Besides, microwave popping sounds can also indicate defective or damaged parts like a diode, magnetron, cooling fan, stirrer motor, and electric circuit. Thus, let’s find out more.

Microwave Making Popping Noise – 10 Reasons

As I said, it is normal for your microwave make popping noise while cooking high-fat food at a high temperature. But it can get quite troublesome if the cracking or popping sound is too frequent and intense.

To fix your microwave’s noise problem, the first thing you need to do is find out where the actual problem is. Well, microwaves have several parts that might cause popping sound issues.

So, you have to check every component for faults/issues. Here are some potential causes of the microwave popping sound issues:

1. Cooking Spray Inside Oven

During cooking or baking in the oven, some people spray cooking oil inside, which can spread inside the whole oven and cause a popping sound.

If this is not the expected problem, you will have to determine whether the food you are cooking has too much fat or not. However, if all of these things are alright, then be assured that your microwave has issues with its components.

2. Faulty Magnetron

Magnetron device is used to generate electromagnetic frequency in the microwave to cook food quickly. This device produces a beeping and tiny popping sound if running at a low frequency.

While running on low frequency, the magnetron constantly turns on and off, so the microwave magnetron noise is also quite normal if it is not that loud.

If the microwave starts to sound like a magnetron, it means that the magnetron’s sound has become loud or high-pitched, which is a bad Indication.

Therefore, it can mean that your microwave’s magnetron might have burnt or its tube might have failed. You might also notice a burning smell if the magnetron has burnt off.

3. Crackling Sound From High Voltage Diode

A high-voltage diode is a circuit that contains a magnetron, capacitor, and diode. Here, its main function is to generate and deliver AC power to the magnetron.

However, you may hear crackling or loud humming sounds from the high-voltage diode if it is malfunctioning.

4. Worn Out Cooling Fan/Fan Blades

With time and long-term usage, your microwave’s cooling fan blades can get misaligned. This can cause your microwave to make a very loud sound.

Therefore, the cooling fan might also get worn out, which can also cause loud noises. Whether the fan blades are misaligned or worn out, the most ideal solution is to replace them.

You should remember that the cooling fan will make a little sound while operating, which is quite normal. As well as, you should only replace the cooling fan when it is making an excessively loud sound.

5. Screeching Sound From Turntable Motor

The turntable motor rotates the glass tray and ensures that your food is evenly heated. Well, this motor often wears out as the microwave ages.

After that, the motor makes a screeching sound while rotating. Further, you never be able to repair a worn-out or rusted part from the motor. So, replacing the turntable motor is an ideal solution.

6. Microwave Coupler

Coupler is the support where your microwave’s turntable motor is adjusted. Sometimes the coupler can also get imbalanced, which can cause a variety of sounds.

Moreover, the coupler can also get rusty, which can also cause screeching sounds from your microwave.

7. Stirrer Motor

Microwaves have a stirrer that is similar to a fan blade and powered by a motor. It is used for spreading heat and deflecting microwave energy uniformly.

The stirrer motor also gets worn out after a long time of usage, which can cause the microwave making weird noise.

You can easily figure out whether your microwave’s stirrer motor is faulty or not by checking the food cooking quality.

If the food is not evenly cooked, it means that the heat spreading and energy deflection are not accurate, resulting in a malfunctioning stirrer motor.

8. Electric Circuit

An issue with your microwave’s electric circuit can cause it to make a sound. A breakdown in the electrical insulation or a faulty component within the circuit can create an arc that jumps through the air or across a gap.

This arcing produces a popping sound similar to that of a microwave spark, and it can be potentially dangerous if left unattended.

In the case of the electric circuit, you might face frequent auto turn-offs, smoke, and other glitches along with the sound.

9. Malfunctioning Thermostat & Vent Fan

When your microwave’s thermostat fails to start the vent fan, the microwave will keep making popping sounds even after it is turned off. The problem is mostly with the worn-out vent fan, which can be replaced.

However, if the thermostat sensor is at fault, you will need to consider buying a new microwave.

10. Microwave Making Sound When Not In Use

A microwave can make sound even when not in use due to the operation of its cooling fan. It continues to run for a short period after cooking to cool down the internal components, which can cause audible noise.

Facing this situation where your microwave makes noise when turned off will make you even more concerned.

You will mostly face such problems with a very old microwave, but there’s still a cause and solution.

Repairing To Fix Microwave Popping Sound

Now that you know the main culprit of the microwave popping sound.

Here is a step-by-step guide on how you can fix your microwave’s components:

Cleaning The Cooking Spray

You can easily fix the cracking noise issue due to spraying cooking oil by cleaning the cooking spray. As well as, stopping spraying oil for good is a sensible choice as it can cause other issues.

And if the reason is simply the food contains high-density fat (rib-eye steaks), you need to try another method. As a solution, you have to decrease the temperature and cook for more time than usual.

Fixing/Replacing Burnt Magnetron

You can check whether your microwave’s magnetron is still working or not by following the few steps below. But make sure you have a multimeter beforehand to follow these steps thoroughly.

So here we go:

  • Firstly, turn off and make sure your microwave is plugged off from the power outlet.
  • Remove your microwave’s casing and locate the magnetron and high circuit voltage.
  • Please take out the capacitor or discharge it completely.
  • Check the magnetrons continuity with the multimeter.
  • Monitor the multimeter reading (it shouldn’t read more than one ohm)
  • Remove and replace the magnetron if it’s faulty.

Read High Voltage Diode Resistance

Reading high-voltage diode resistance will help you learn about its continuity. As well you should be careful while following these steps because the diode might still contain a dangerous amount of electricity.

So, let’s get a high-voltage diode reading:

  • Unplug the appliance and remove the microwave’s top casing.
  • Locate and get access to a high-voltage diode and discharge the capacitor.
  • Utilize a multimeter to verify the high voltage diode, which should read between 50k-200k ohms if the diode is not damaged.
  • Reverse the leads and read the diode resistance rate another time. (You have to make sure that there is no continuity in any direction).
  • If the diode’s reading is not within 50k-200k, you have to replace it with a new one.

Clean/Replace The Cooling Fan Motor

The cooling fan may not be spinning freely because of dust buildup or is just worn out. You have to either clean or else change it into a new one by accessing the fan motor.

Regarding this, some microwave models require removing other components to access the cooling fan. You have to follow your microwave’s instruction manual in this case and resolve the microwave making popping noise:

  • Locate and access the cooling fan component.
  • Check if the fan is spinning freely, search for debris around it, and clean it.
  • You also have to check the cooling fan motor for any debris and if the motor is working.
  • Utilize a multimeter to verify whether the motor has continuity or not ( It should read around 280 ohms).
  • If the multimeter doesn’t read around 280 ohms, indicating the motor isn’t functional and requires to be changed.
  • In case the multimeter is functional, you should clean the debris.
  • You might also need to change worn-out cooling fan blades.

Adjust Stirrer Blade Position & Motor

If the problem lies within the stirrer blade of your microwave, you can fix it by either adjusting the blade position or fixing/replacing the motor:

  • Locate the stirrer blade motor placed right above the turntable plate.
  • Access the stirrer motor by opening your microwave’s cavity.
  • There is a cover around the motor; you need to remove it for easy access to the blades.
  • Now verify if the stirrer blade is aligned in its position or not.
  • You should also check the blade’s condition and ensure that it is tightly attached.
  • Get replacement blades if the old ones are beyond repair.
  • Check your microwave’s sound by removing the stirrer motor. If the noise stops after removing the motor, you will have to replace the stirrer motor.

Checking Turntable Motor

The microwave’s turntable motors are located below the support roller. You can easily access them and inspect the motor to find any defects that can cause noise by following these instructions:

  • Firstly, remove the support roller and glass plate from the microwave (You can remove them by just opening or unscrewing them, depending on the microwave’s model.)
  • Unbolt and remove the turntable motor panel to access the motor.
  • Test the motor’s continuity using a multimeter and inspect for other issues.
  • Fix any other issue if found, or replace the turntable motor if it shows no continuity.

Caution: Unplug the microwave from its power outlet before checking any of its components. Some components, such as the capacitor, high voltage diode, etc, contain an excessive electricity voltage. It would be best to discharge them every time before you check to access any component.

Final Words

The guideline for fixing the microwave making popping noise ends here. An important factor is that you should be familiar with your microwave’s parts to know if it’s defective or not.

You can easily locate the reason for the microwave popping sounds if you are that much familiar with the microwave. Further, keep your microwave clean and don’t use it too roughly to prevent such issues from occurring.

Lastly, you must understand that your microwave won’t fix every time. Sometimes, your old microwave might sound as loud as an alarm clock or not function at all.

So, you shouldn’t get all worked up with fixing the old microwave and get a new one instead.

Frequently Asked Questions [FAQ]

Is a buzzing microwave dangerous?

A buzzing microwave can be dangerous if left unchecked. The buzzing sound could indicate a malfunction, which could lead to the appliance overheating and possibly catching fire.

If you hear a buzzing sound coming from your microwave, it is recommended that you unplug the device and contact a qualified technician for service.

Why is my microwave making buzzing noise when not in use?

This could indicate an electrical issue, such as a faulty capacitor or transformer, or a problem with the door latch that is causing the microwave to start up without actually being turned on. In some cases, it could also indicate a problem with the magnetron.

Is it safe to use a humming microwave?

Using a humming microwave may be safe, but it is important to take extra precautions. It is best to avoid using a humming microwave if you hear any loud noises coming from the appliance, as this could indicate an electrical problem that could lead to a fire or shock hazard.

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