Repairing microwave fuse -
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How to Fix a Microwave Fuse That’s Blown Out (Questions AND Answers!)

If you’ve ever tried to fix a microwave, then you know it can be a real pain. But if you’re reading this, we’re guessing that your fuse has blown out and now your microwave isn’t working.

Fortunately, this fix is pretty easy.

All you need is a screwdriver, a small pair of wire cutters, and some patience and maybe a little bit of luck too.

What are blown microwave fuses?

Blown microwave fuses are a common problem in microwaves, and they can be caused by a variety of different issues. In most cases, the fuse will blow when there is too much voltage running through it.

This can happen if you’re using an extension cord with your microwave or if you have something plugged into one of your outlets that is not working properly.

In some cases, blown fuses can also be caused by overheating. If the wall outlet is getting too hot or if there’s something wrong with the oven itself—like a bad heating element—then this can cause your fuse to blow.

If this happens, you’ll want to call a professional to take care of it right away before anything else catches fire!

What are the symptoms of a blown microwave fuse?

The symptoms of a blown microwave fuse are:

  • The microwave doesn’t heat up.
  • The microwave doesn’t run.
  • The light in the microwave doesn’t turn on.
  • The display on the microwave is blank.
  • The microwave beeps continuously.
  • The door of the microwave doesn’t open.

If you experience any of these symptoms, it is likely that the fuse in your microwave has blown and will need to be replaced.

How do you know if you have a blown microwave fuse?

There are a few signs that indicate you have a blown microwave fuse.

  • If your microwave suddenly stops working.
  • If the door won’t open or close.
  • If there’s smoke or sparks coming from the microwave.
  • If the display is dim or flickering.
  • If the microwave is making strange noises.

If you notice any of these signs, it’s important to check the fuse and replace it if necessary. Fortunately, this is a relatively easy task that you can do yourself.

What causes blown microwave fuses?

Power surges

Power surges are caused by lightning strikes, or power problems in the area. They can also be caused by a nearby appliance or computer that’s not plugged into a surge protector.

A surge protector will protect your appliances from these surges and keep them from blowing fuses, so it’s important to make sure you have one for each of your appliances.

A non-functioning cooling fan

Your microwave has a cooling fan that keeps it from overheating, but if it stops working, the fuse will likely blow because of excessive heat build up inside the device.

Sometimes this can be caused by dust buildup on the cooling fins or just general wear and tear over time.

If you notice that your microwave isn’t cooling off as quickly as it used to be, check out our guide on how to clean your microwave for more info on how to fix this problem.

A short circuit in the controller

A short circuit in the controller is also one reason why microwaves blow fuses.

This means that electricity has leaked onto another part of the machine and caused damage there as well as possibly ruining other components inside your microwave oven as well.

A short circuit in the power cord

The most common cause of blown microwave fuses is a short circuit in the power cord. A short circuit occurs when electricity flows through a path that is not designed to conduct electricity.

When this happens, it causes heat and sparks, which can damage the cord and lead to an explosion.

A short circuit in the magnetron

Another common cause of blown microwave fuses is a short circuit in the magnetron.

The magnetron is what produces microwaves in microwaves, so if it has a short circuit it will not produce microwaves and your food will not be cooked properly.

A short circuit in the high voltage diode

Another cause of blown microwave fuses is a short circuit in the high voltage diode.

This device prevents electricity from flowing from your appliance into your home’s electrical system. If there is no protection against this happening, it can cause serious damage to your appliances and even start fires!

A broken door interlock switch

This switch prevents the microwave from running when the door is open. If this switch is broken, it may cause your microwave to heat up and blow its fuse when it should not be operating.

The door not aligned properly

If the door becomes misaligned, it can cause damage to internal components and cause those parts to overheat and blow the fuse.

An overloaded circuit

If there is too much power being drawn on one circuit (such as with multiple appliances on one outlet), this can cause a short circuit and blow your fuse.

A ground fault

A ground fault happens when there is a short circuit between the neutral and ground wires inside your microwave.

This can happen when you have worn or damaged wiring in your home, or if the outlet where your microwave plugs in isn’t properly grounded.

An arc fault

An arc fault happens when there is an electrical arc (a bolt of electricity) between two parts of the circuit board inside your microwave. It could be caused by a faulty heating element, cooling fan, relay switch, or capacitor.

How do you prevent blown microwave fuses?

The best way to prevent blown microwave fuses is to:

  • Check the microwave for any signs of damage before using it.
  • Make sure the microwave is properly ventilated.
  • Don’t use the microwave if it’s been damaged or is not working properly.
  • Don’t overload the microwave.
  • Don’t use the microwave if the power cord is frayed or damaged.

Should you repair or replace a blown fuse?

A blown microwave fuse is a common issue that can be easily fixed. However, depending on the severity of the issue, you may need to decide between repairing or replacing your microwave.

This decision will come down to cost, time, and the age or condition of your microwave.

Can you fix and repair a blown microwave fuse?

Microwave fuses go out more often than you might imagine. The replacement process is as simple as following these steps:

  1. Disconnect the microwave from any power source.
  2. If you have a microwave that has been installed in a cabinet or that is an over-the-stove model, take the time to remove the microwave and take it to a place where repair is safer and easier.
  3. Remove the access panel.
  4. Locate the blown fuse, you can usually see the fuse as a blown fuse might look blackened or charred.
  5. Test the fuse after removing it with a multimeter.
  6. If the fuse is bad, replace it with the same type of fuse.
  7. If the fuse is not bad, you may have a bigger issue.

How to replace a blown fuse

Replacing a fully blown fuse is a must. If you have a fuse that is out there is really no way to keep using the microwave with a blown fuse.

There are some signs you can look for if you think that your microwave may have a blown fuse. Microwaves with a blown fuse are not going to work. They are not going to start, and they are not going to have the necessary continuity to start and run with a blown fuse.

If you have experienced a power outage or a surge in power, you may have noticed a pop or the sound of the fuse blowing or the microwave may have been working and suddenly stopped.

To see if you have a bad fuse:

  1. Remove the access panel and find the fuses.
  2. Test the fuses with a multimeter for continuity and to see if the fuse is good or bad.
  3. You may have multiple fuses out. Test all fuses to see if they are working.
  4. After replacing the blown fuses, test the microwave by heating a cup of water for 30 seconds.

How to test a microwave fuse

Testing a microwave fuse is not a super difficult thing to do.

You can remove the fuse from the back of the microwave that you suspect might be blown, then use a multimeter to determine if the continuity of the fuse is intact. If is it, the multimeter will show that there is continuity.

If the fuse is blown, the multimeter will not react. You can also look for char or blackened fuses, in some cases, you can see the inside of the fuse, and you can tell that it is not working.

Where to find a new fuse

You can buy new fuses from nearly anywhere.

You can get them from your local hardware store, from the manufacturer of your microwave, or from the store where you purchased your microwave.

The thing you need to keep in mind is that you do need to ensure you are getting the right fuse when you purchase. The wrong fuse if is it not large enough is going to blow out again, one that is too large may not work either.

It is important that you only use the fuse that the manufacturer recommends ensuring that you are going to be replacing the correct fuse to ensure your microwave keeps functioning properly and safely.

How many fuses are in a microwave?

There are at least two fuses in any microwave regardless of the make and model and size.

The first is the main fuse or the line fuse that is used to supply the main power to the microwave.

There is also the thermal fuse or thermoprotector that ensures that the microwave does not overheat and that it stays within the bounds of the manufacturer’s intent.

There may be more fuses in other models, but all models have at least two fuses within them to help them function properly.

Three types of fuses for microwaves

Thermal fuses

Thermal fuses are also used in newer models of microwaves. They look like small cylinders that contain either carbon particles or metals like iron or zinc.

When too much current flows through them, they heat up until they melt, which opens up an electrical circuit so no more power can go through it until it cools down again (usually about five minutes).

Glass fuses

Glass fuses are generally used in older models of microwaves. They are made of a glass tube with metal ends and a metal wire inside. Glass fuses are easy to replace, and they’re less expensive than other types.

Ceramic fuses

Ceramic fuses are more commonly used in newer microwaves.

They have a ceramic body that contains a metal wire that melts when there is too much current flowing through it, which protects the rest of the circuitry from damage.

Ceramic fuses are considered safer than glass fuses because they won’t break if you drop them and prevent electricity from flowing through them if there is any moisture inside them after being dropped—which could cause an electrical fire if you don’t notice it immediately!

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