Microwaves like any other electrical appliances have fuses to operate safely. In case the operating conditions become unsafe, fuses blow to protect the microwave and the user of the appliance.
Microwave fuse blown symptoms are –
- Microwave is not working at all.
- No response on pressing any buttons or touchpad.
The reason for blowing of microwave fuse depends on when it happens. It can happen if the high-voltage capacitor has shorted out and as soon as you press Start, the fuse blows. However, if there is a faulty door switch, the fuse blows when you either open or close the microwave door.
Microwave fuse is one to two inches long, It can be either a glass fuse or a ceramic fuse. A glass fuse has a filament and it is easy to tell if it is blown, It will have scorch marks with melted filaments.
A ceramic fuse can be tested by using an ohmmeter or continuity tester. If the reading in the ohmmeter is zero ohms, it means the fuse is intact whereas if the reading is infinite, it indicates blown fuse.
To test with a continuity tester, touch the ends of the fuse with the lead of the tester. If it shows continuity, the fuse is good.
Fuse keep blowing in microwave, what to do?
Sometimes even after replacing the blown fuse of the microwave, it blows again as you try to cook anything. It might happen as you start heating or open the door of the appliance. You replace that fuse but the same thing will happen again. Or it may run for a few days and then blow again.
If the fuse keeps blowing in the microwave, you must do the following things:
- Check the cooling fan for any object being lodged in the fan which stops it from rotating. Dead or ineffective cooling fans can be a reason for continuous blowing of the fuse. In case you find something in the cooling fan, remove it. Accumulated dust and grease might obstruct the airflow so fan and vent must be cleaned properly.
- There may be a loose screw or a piece of metal that is causing a short circuit. If there is anything loose, you may be able to get it out. Once it is known, tighten it and the problem of continuous blowing of the fuse will be solved. Always discharge the capacitor first and then touch any interior metal. Use needle-nose pliers with well-insulated handles to get things out safely.
- The fault may be with the door interlock if the fuse blows as soon as you open the door. The design feature of the microwave is such that microwaves could leak out if the door is not closed properly. In such cases, multiple small components have to be replaced and it is good if you get it done by a trained technician.
- Blowing of the fuse can happen when the high-voltage capacitor has shorted. It is dangerous to touch a charged capacitor but it can be replaced once it is discharged.
Where is the fuse on a microwave?
There are two types of fuses in the microwave, ceramic and glass fuses. The fuse on a microwave can be at any place depending on the model of the microwave.
To know the exact location of the fuse in a microwave, consult the wiring diagram printed on the inside cover of the microwave.
In some microwaves, the fuse can be behind the control panel or vent grille. This fuse can be accessed without removing the microwave from its installation but you will need to remove the grille or control panel.
Sometimes, fuses are located inside the microwave in different places like on the top, side, or behind the vent grille. The exact location of the fuses can be determined with the help of the wiring diagram.
How to replace fuse in microwave?
Below are the steps to follow to replace a fuse in the microwave:
- Unplug the microwave and disconnect it from the power source.
- Consult the wiring diagram of the microwave and find the exact location of the fuse. Depending on this, unscrew either the control panel or microwave frame.
- Once you find the fuse, unscrew or unclip it and remove it from the microwave.
- Use a multimeter to test the fuse for continuity.
- If found defective, replace it with a new fuse that matches the blown fuse.
- Reassemble the microwave and restore the power.
- Microwave a cup of water for 30 seconds to test the new fuse.
How to test microwave fuse?
In a microwave, there can be either a glass fuse or a ceramic fuse. The glass fuse comes with a filament and to test it, you need to observe the fuse. A glass fuse is blown if it shows scorch marks and filament in melted state.
To test a ceramic microwave fuse, use an ohmmeter or continuity tester. Touch the testing probes of the ohmmeter with the metallic ends of the fuse. If the reading is near zero, it indicates the fuse is intact. Whereas if the reading is very high or infinite, it means the fuse is blown.
What amp fuse do I need for a microwave?
A 20 amp fuse will be needed for a microwave. It is the standard fuse used for most of the microwave of 700-1000 watts.
Sometimes, the fuse of the microwave blows away. In that case, you have to replace the fuse with the same amperes only. Placing a fuse in the microwave with different or high amperes can dump more current into that short circuit causing a fire hazard.
There can be either a glass fuse or ceramic fuse in a microwave and these prevent the microwave from short-circuiting whenever there is voltage fluctuation.
Conclusion
A fuse in the microwave blows to prevent short-circuiting in the appliance whenever there is any short circuit. Thus, the microwave is protected from any kind of damage.
If your microwave suddenly stops working or there is no response on pressing the buttons, you may consider that the fuse is blown away.
However, it is always better to confirm it by inspecting the fuse. In this way, you could diagnose the problem properly. Hope this article gives you enough information about the fuse of the microwave.
Happy Cooking!