What are the symptoms of a blown fuse in a microwave?

Author: Selena Strosin  |  Last update: Wednesday, June 4, 2025

* Fuse blows when microwave shuts off (during or at end of cook cycle). * Oven heats on high setting regardless of power setting. * Oven immediately starts to cook when door is closed. * Oven heats but power seems low or erratic.

What happens when a microwave fuse blows?

If the fuse blows when you run the microwave it means that either your magnetron is grounded out, or one of the door switches has failed.

Can a microwave work without a fuse?

Yes. Microwave ovens are typically on a circuit by themselves which is protected by a breaker that is not shared with any other device.

How much does it cost to replace a microwave fuse?

The cost to replace a microwave fuse typically ranges from $10 to $30 for the fuse itself, depending on the model and type. If you hire a professional to do the replacement, labor costs can add an additional $50 to $100, bringing the total to around $60 to $130.

Can I replace a microwave fuse myself?

Microwave repair requires extreme caution, even if you are only replacing one fuse. Microwaves use much higher voltage than other common appliances, and can cause serious injury or death if handled incorrectly. Only people experienced in electrical repair should attempt this.

Top Reasons Microwave Is Not Working — Microwave Oven Troubleshooting

Is it cheaper to fix a microwave or replace it?

The average cost to repair a microwave varies based on the issue. Most of the time, repairs are significantly cheaper than a replacement.

How do I know if my appliance fuse is blown?

Firstly, visually inspect the fuse and see if the filament inside is intact or broken. A blown fuse typically has a broken filament and a black or gray discoloration around it. Secondly, if your device isn't working despite being plugged in and switched on, it's likely that the fuse has blown.

Why would the microwave suddenly stop working?

Reasons: Control panel issues: A malfunctioning control panel can prevent the microwave from responding to your inputs. Fuse problems: Blown fuses can interrupt the power supply to the microwave. Power cord damage: A damaged or disconnected power cord can prevent the microwave from receiving power.

How long should a microwave last?

With normal usage for an average family and good maintenance, a microwave often lasts for 7 to 8 years. If the microwave is used less frequently by a single person or a couple and is well-maintained, the lifespan can increase to up to 10 years.

What does a burnt microwave fuse look like?

A blown glass fuse will produce flash burn marks on nearby surfaces, or it will be completely black on the inside.

What is the most common cause of microwave oven failure?

One of the more common causes of microwaves not heating up is a faulty magnetron. This is what generates all those microwaves in the first place. If this burns out, or there is an electrical fault in the machine.

Will a blown fuse cause a microwave not to heat?

Typically, if the microwave is not heating, a door lock or blown fuse will be causing the issue. If the fault is more serious, the high-voltage capacitor, magnetron, or diode may need to be replaced. To determine the cause of the heating issue, these parts will need to be troubleshot, starting with the door switches.

What happens to the appliance if the fuse blows?

At a minimum, a blown fuse or tripped circuit breaker will render a washer, refrigerator or other appliance inoperable until the fuse is replaced or the breaker reset. In some cases, the problem could be caused by a frayed wire or a loose connection that needs to be fixed immediately.

What causes microwave to trip breaker?

One of the most common causes of a microwave tripping a circuit breaker is overloading the circuit. Microwaves draw a significant amount of power when operating, and if the circuit is already handling a heavy load, it may not be able to handle the additional demand.

How do you know if a fuse needs to be replaced?

Look at the fuse wire. If there is a visible gap in the wire or a dark or metallic smear inside the glass then the fuse is blown and needs to be replaced.

How do you detect a fuse failure?

The blown fuse will be apparent because the wire element within will have melted or burned from the higher electrical current. You can also leverage diagnostic tools like a test light or a multimeter to identify the dead fuse without having to pull it out. Both devices are affordable and easy to use.

Can I replace a fuse myself?

Replacing a fuse is a relatively easy, do-it-yourself home task that you can tackle with a little information and some electrical home safety savvy. If your home has a fuse box, the best advice is to plan ahead and become familiar with the electrical panel and with the types of fuses it requires.

Does unplugging a microwave reset it?

Keep the microwave unplugged for 5-10 minutes. The waiting period allows the internal components of the microwave to reset, ensuring a clean slate when you plug the microwave back in and reprogram your desired settings. Check for any evidence of damage on the plug and outlet before plugging them back in.

What causes microwave buttons to stop working?

The control panel might be defective

The most common cause of your microwave buttons not working is a faulty control panel.

What is the life expectancy of a microwave?

The average microwave oven lasts about seven years with normal use, and even less with heavy use and poor maintenance. A large family may find themselves replacing their appliance every four to five years as they become more reliant on its use to heat up snacks and leftovers, or to defrost meals.

Is it worth repairing a 7 year old microwave?

Factors to Consider

Age of the Microwave: Microwaves typically last about 7 to 10 years, so if yours is in the 7-year range or older, repairs might only offer a temporary fix, making replacement the better long-term option.

How to know when a microwave is going bad?

When to replace the microwave? Common signs that your microwave needs changing
  1. Making funny noises.
  2. Smells like electrical burning.
  3. Isn't cooking food in the usual time or cooking unevenly.
  4. Needs help to work properly – such as a spoon to hold the door closed.
  5. Keypad has stopped working.

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