Why Is My Microwave Popping Noise?

On a lazy day, you want to ignore all the cooking routines and enjoy yourself on your couch! A microwave oven will take over all your cooking. Also, you can opt to reheat last night’s leftovers. The oven is an all-rounder. But you have just noticed some rare sounds from the cooker. You need to learn why your microwave is popping noise.

If your microwave makes a loud popping noise, it could be your sizzling food. But also, you cannot ignore ominous signs such as arcing. Popping happens when you place metallic objects like cutlery in the cooker. It could also be debris and uneven cooking. Never ignore a popping noise from your microwave oven.

Stay here and learn more.

Why Does My Microwave Make A Crackling Noise When Not In Use?

You have already gotten a snippet of why your microwave is popping noise. Mainly, this occurs when you are cooking. The cause could be boiling food, arcing, uneven cooking, and debris in the oven. Other microwave noises, such as humming should not worry you. Unless it is a shrill, a low hum is not strange, as microwaves are usually noisy. 

Occasionally, your microwave might scare you with a cracking noise when not in use. If that is the case, some components may be failing. The problem could be;

  • Overheating parts
  • Standby mode
  • Electrical faults
  • Failing magnetron
  • Faulty diode
  • Fan 
  • Transformer

You cannot ignore an oven that makes strange noises when it is not working, so you must inspect it further. I will discuss the above seven microwave issues and tips to resolve them.

  1. Overheating Parts

After cooking, your appliance remains hot for some moments. Before a complete cooldown, you may experience a cracking noise. The thermostat detects the heat and signals the fan to continue functioning to cool down the hot parts.

So, the fan will continue to run even after your appliance is off. Don’t worry; it will stop when most of your microwave parts cool down. What if the crackling noise doesn’t stop? Check the electrical connections.

2. Standby Mode

After cooking, you may have forgotten to switch off the wall socket. If you didn’t, your oven is still on and on standby mode. The power flow keeps the timer and other functions on, hence the strange crackling noise. Check if the plug is still on the socket and unplug it.

3. Electrical fault

Electrical faults such as a short circuit or a twisted power cord can cause crackles. It happens if you don’t switch off the gadget or the life wires come into contact with water. The popping or crackling sound is a warning that your appliance requires maintenance.

Good kitchen practices include fixing broken electrical circuits, plugs, wires, and other components. Also, keep your machine disconnected from the electric source when not in use.   

4. Failing Magnetron

As your microwave ages, the most active components also become weary. The magnetron remains active throughout the oven’s performance. The part begins to experience issues and dwindles in releasing electrons that generate heat. As a result, your gadget can no longer heat as it used to when it was new. 

In some instances, you might experience crackling when your oven is resting. The magnetron will begin clicking and snapping. In normal operations, the magnetron might click, but if the noises are more pronounced and irregular, count your blessings and move on. A newer appliance will give you peace.  

5. Faulty diode

The diode powers the magnetron with Direct Current (DC). It is the feature behind the humming that you hear from your microwave. The hum only happens when the oven is running. When the gadget is off, the diode is silent.

After the machine’s timer is off or the cooking time is over, the diode stops. You may hear some crackling noises as the oven cools down, but these should not be too pronounced. So, a loud and long crackling sound when it is off should raise your antennae.

Talk to your repair experts or call the manufacturer and tell them what your oven is experiencing. It could be a faulty diode that needs a replacement.

6. Fan 

The fan cools down our gadget by blowing out hot air and fanning cool air into the machine. This action ensures that your microwave does not overheat. After removing your food from the oven, the fan cools hot components. During the process, your oven may crackle, but the fan will stop when everything cools down.

But you must consider fan problems. A faulty fan motor, broken blade, or switch can cause noise. If you have narrowed down the sound to the fan, you can open apart the machine and do an inspection. Call your dealer or repair clinic if you are still getting familiar with the process.

7. Transformer

Your microwave has a transformer that converts the electrical power into a higher voltage that can cook your food. When the oven is on, this unit hums but is not loud. The noise may continue even after the cooking. If the transformer continues to crack long after your oven cools down, you need to consult an expert.  

What Are The Signs That A Microwave Is Going Bad?

Its no doubt that a microwave oven is a low-maintenance countertop appliance. Once you purchase one, it stays in good condition for a long time. That is, as long as you are using the oven right. 

Nevertheless, it would help if you had pointers to tell when your microwave is going bad. Open your eyes if the oven is not cooking your food well, has a burning smell, or has an irresponsive control panel. Your gadget could be going bad and needs repair or replacement. 

There are more signs, so keep reading!

  • Irregular Cooking/Defrosting/Heating

Have you experienced delays when cooking, defrosting, or heating your food? That’s a bad sign on your microwave. If you do not take prompt action, it could stop functioning anytime. A turntable turning doesn’t mean your oven is cooking. 

Major components such as the magnetron and the turn table may be faulty. Also, other crucial features such as the diode, transformer, electrical wiring, and waveguide cover may have failed. 

To pick out the problem, you must test each component. That way, you will be sure of what you are treating. An expert can do this task better. 

  • Burning Smell/Arcing

A burning smell, a spark, or smoke are telltale signs of a faulty appliance. These three also signify electrical faults and many more defects. Establish if the burning smell comes from the food before you take action. If your food is not burning, something more serious is happening.

Observe your unit for arc and listen if there is a popping sound. If so, the first thing will be a check if you placed a metallic object or foil in your oven. Also, some foods come with foil-lined packaging, e.g., milk and sauce. Be sure to microwave your food in friendly dishes such as glass and silicon. 

Never use steel wool scourers to clean your oven. Besides scratching off the paint, they leave chards in the oven, which spark when you run your oven. Remember that a spark is dangerous. It can cause fire and raze down your home, so disconnect your appliance immediately and call a specialist.

  • Irresponsive Controls

If you apply force when pressing the controls, there is a problem. Microwaves have user-friendly buttons that are smooth to push. The controls respond super-fast. Whatever your model, the interface should not cause you pain. The touch screens are super easy to use but can have issues if the surface is dirty. 

Make an effort to wipe your oven’s control to prevent sticky situations. An irresponsive touch device may also be due to an error in the control unit. If you are good at electronics, you can give it a trial, but the best option is to get an expert to check it for you. If the oven has served you for the last decade, that’s obsolescence. Begin a new chapter by purchasing a new model.

  • Strange Noise

Popping, crackling, shrilling, and other strange noises are easily identified in an appliance. The causes could be a faulty transformer, fan, diode, magnetron, overheating, or even a dying machine. Read more about why your oven makes strange noises and narrow down the cause. 

  • Unsealing Door

Is your oven’s door sealing? There should be no spaces on the edges when you close the door. The door should lock well and keep the interior airtight. The sealing keeps radiation within the cooking compartment. A worn-out or cracked door cannot seal properly, thus a sign of a broken appliance. Do not cook with a microwave that is not sealing well. Depending on the age of your oven, you can call your dealer for warranty claims, repair, or replacement. 

  • Stopping Mid-Cooking

After setting the cooking time, your oven should run until the end. Although the unit can stop mid-cooking due to power loss, it is crucial to check for other possible defects. Stopping midway could also mean a broken timer, overheating, being overworked, or a worn-out appliance. Overusing your microwave can have adverse effects, including a breakdown.  

  • Running Without Heat 

Your microwave is on and rotating, but it is not cooking or heating your food. That’s a sign that the oven is slowly failing. The primary issue might be the magnetron, diode, or other components. While you may want to replace the broken parts, a new microwave will serve you better. Get a technician to identify the problem and advice the best resolution.

  • Stationary Turntable 

The turntable spins to ensure that your food gets heated evenly. It rotates with the help of a drive motor and drives coupler. With the roller guide, the unit can spin around in the cooking chamber. 

If the microwave turntable is not spinning or is rotating at snail speed, the components have a problem. The roller may be out of place, or the motor/coupler is broken. You can replace the roller guide, but the drive motor requires expertise. Due to its complex functionality, a microwave is expensive to repair and replace parts. Plan to get a new one.

  • Old Age

Like humans, machines grow old. So, do not expect your microwave to cook for decades. They, too, expire and bid you bye. Signs of old age include failing controls, less heat, slow cooking, and stopping mid-cooking.

After using a microwave for five years, do not expect its functionalities to be at par with your expectations. It is time to change to a newer model. Check out our guides on the best countertop and built-in microwaves.

Why Is My Microwave Making Sparking Sound?

 A spark from your microwave will scare you. You might consider kicking the unit out of your kitchen, but this might be optional. If your microwave makes a sparking sound, perhaps you left metal items in the cooker. It could also be the waveguide or not some food craps in the cooking chamber. A faulty diode or magnetron causes sparks in microwaves.

Luckily, you or your repair center can fix all the above issuesOnly in rare instances will you find the problem stubborn. If the sparking fails to go away after the attempts to resolve the issues, replace the unit. It is a hazard in your home. 

Learn in detail why your microwave is making a sparking sound;

  1. Metal Fragments In The Microwave

In most microwave dos and don’ts, you will find disclaimers not to insert metallic materials in your microwave. These include aluminum foil, cutlery, metallic bowls, foil wraps, steel wool, and other metallic fragments in the oven.

If you forget your knife in the machine and run it, you will experience a scary sight. Sparking will occur and can hurt your microwave. Cleaning your oven interiors with steel wool scrubbers can leave small metal strands. 


  • Do not use steel wool scrubbers in the microwave. A soft cloth is ideal for cleaning your microwave to prevent sparking.
  • When microwaving food, never leave cutlery in your dish.
  • Use silicon, glass, or ceramic bowls for cooking or warming your food.
  • Empty milk from foil-lined papers to sparks.
  • Do not use aluminum foil in your microwave.

2. Damaged Diode

The diode’s work is to change AC to DC for the magnetron to use. In turn, the magnetron releases electromagnetic waves to cook your food. The function is quite complex as it uses high electric current and voltage.

A damaged diode may discharge sparks. That’s dangerous as it can burn you or cause a fire. An easy way to determine a damaged diode is through smell. Your oven will emit a burning smell.


Fixing a damaged diode isn’t practical. It calls for a test for continuity and replacing the unit or the entire microwave. Disconnect your gadget from the power source and unscrew the access panel.

Once you access the diode, test its continuity and change a spoilt one. Be careful with the unit as it contains high and lethal electric currents that can harm you. This procedure can be quite involving. If you find it complicated, ask an expert to assist you. Also, a diode replacement is costly. Some people find it easier to buy a new microwave.

3. Faulty Magnetron

As I detailed above, the magnetron’s work produces heat to cook your food. Your electrician will point out that the function doesn’t cause flickering. However, this depends more on the model when the magnetron deteriorates. The microwave may spark, but a common sign with a dead or worn-out magnetron is failure to heat food.   


Like the diode, you can access the magnetron and test its continuity. You can then determine if a part replacement is better or not. It is cheaper and more reliable to buy a new oven. Find a safe way of disposing of your damaged microwave.

4. Weary Racks

Microwaves that come with metal racks may spark, especially if worn out. The stands come with a plastic surface that coats the metallic surface.

Remember that we said metals in a microwave oven cause sparking. The shield is designed to prevent arcing/sparking. When this thin layer erodes, it exposes the metal to the oven’s metallic surface. But you do not have to use a worn-out rack!


To resolve to spark due to metal contact, replace the weary rack with a new one.

5. Dirty Microwave

A common cause for the sparking sound in your microwave is dirt. That includes food residues, grease, and splatters. If you run a dirty microwave, you will experience flickers as the magnetron burns the food residues.


Clean your microwave often and after every cooking.

6. Faulty Waveguide Cover

The waveguide cover is the small square panel inside your microwave’s cooking compartment. Its work is to transfer waves from the magnetron so that the heat can cook your food. If it is faulty, it can cause flickering—also, a dirty wave guide spark. Frequent sparks from the faulty magnetron, diode, weary racks, and metallic chips can damage the waveguide. 


Take care of your microwave’s waveguide, which is an essential part of your machine. Clean the cover and often examine the feature for damages. Unfortunately, you cannot replace a damaged waveguide. The only resolution is to buy a new microwave.

Is It Normal For A Microwave To Crackle?

The most identifiable microwave is humming. It is the noise that most ovens make when running. The noise emanates from the diode and the transformer. These two are responsible for the power supply inside the oven. Although the fan may crackle during the cooling process, most other noise is far from ordinary

So, it may not be customary for a microwave to crackle. The noise may be alert of underlying issues, including a damaged diode and magnetron. It is even more harmful if the crackle combines sparks.

The crackle, which may also spark when the oven runs, can damage your unit. 

Often, the sparking occurs on the food wrap (if it is aluminum foil) or on metallic objects that you left in the dish.

A crackle may also happen due to a faulty or dirty waveguide. You can clean a dirty one, but you cannot replace a damaged waveguide.

In summary, have a look at what could be causing a crackle in your microwave;

  • Loose blower wheel
  • Faulty diode
  • Damaged fan
  • Faulty magnetron
  • Fan’s cooling operation
  • Metal dishes, cutlery, steel wool, and metal chips in the oven
  • Dirty/damaged waveguide
  • Chipped rack
  • Food spills
  • Sizzling food
  • Misplaced turntable unit (glass plate, roller, and track)
  • Fatty foods
  • Overheating parts
  • Standby mode

Most of the causes of crackles in your microwave are alerts about some failing components. Others are normal functioning of your oven, for example, sizzling and fan cooling operations. You must narrow down the causes of the strange noise and resolve accordingly. Do not ignore any popping sound or abnormal sound from your microwave. I recommend that you conduct regular maintenance practices on your gadget. That keeps it in good condition and safe to operate.

Safety when handling a popping microwave is paramount. Here are ways to safeguard yourself from a faulty appliance;

  1. Identify the sound to determine if it is a standard operating process of the oven. Here are the noises that come from a microwave
  • Humming
  • Popping (crackling)
  • Clicking 
  • Rattling
  • Shrilling
  • Grinding
  • Electric sounds (short circuits)
  1. Beware of louder-than-average humming, as it may signify a significant problem.
  2. Never use a sparking microwave. If you notice flickers, disconnect them from the power source. That can cause severe damage to your oven or an explosion.
  3. When testing the parts for continuity, beware of the components, such as the diode and capacitor. These carry high voltage and can injure you.
  4. Always use a multimeter to test your microwave’s continuity. 
  5. If you need help with how to repair your oven, contact a technician.
  6. Use the correct microwave spares to prevent arcing and other damage to your microwave.
  7. Follow the manual specifications to safeguard your oven from sparking, popping, and other dangerous occurrences.
  8. Use microwave-friendly utensils. Never put metal things in your oven.
  9. Observe routine maintenance of your microwave. Clean the oven after use to prevent spills and food residues from sticking on the waveguide, magnetron, and turntable.
  10. When every trick fails, talk to the manufacturer. The service guys there understand all the features of your microwave. 

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