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Is your microwave not working, even though it has power? We’ll show you the most common reasons for this experience.
In some instances, it can be as simple as resetting the GFCI switch. In other cases, it might be issues with the turntable, a door switch, or blown fuses.
Microwave not Working: Won’t turn on
Rule #1 for troubleshooting: Always start with checking the easiest things first. Don’t assume anything.
Before I jump into diagnosing the microwave itself, the first thing I check is whether or not there is power to the microwave wall outlet. Don’t take it for granted that your outlet is live. Test it with a known good appliance or lamp to be sure.
If any lights are illuminated on your microwave display, then your unit has power. Move on to the next section.
If the outlet is dead, it might be because the GFCI (Ground Fault Circuit Interrupter) switch needs to be reset. This GFCI mechanism can be either at the outlet itself, at an outlet upstream from that one, or else at the circuit breaker.
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Note: A built-in microwave typically is not protected by a GFCI. However, most countertop units will be plugged into a kitchen outlet, which should be on a GFCI-protected circuit (homes built pre-1990 can be an exception).
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If the circuit breaker is on, but you still don’t have power to the outlet, there is likely a GFCI outlet hiding somewhere that is tripped. Check all kitchen outlets, including dining and nook area outlets.
Related: Samsung Microwave Error Codes
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Blown Thermal Fuse
Once you’ve determined that the GFCI outlet isn’t what has caused a lack of power to your microwave, one issue might be a blown fuse in the microwave.
Some things which indicate this is the case include
- The microwave powers on but won’t work
- A thermal fuse stops electric current flows to your microwave as a safety setting. It helps prevent the microwave from overheating. Using a multimeter, you can check to see if the fuse lacks continuity
- If there’s no continuity, it means the fuse needs to be replaced.
Slammed Door Causing Malfunctions
A second common reason your microwave malfunctions is that you have slammed the door shut, and now it won’t turn on.
This is an indication that there’s a blown fuse in the microwave. Check the fuse using a multimeter to check for continuity; if it’s blown, you’ll have to replace the fuse.
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Buzzing but not Heating
A power diode failure is what you’re probably experiencing in these situations.
If the microwave is buzzing or humming, but it isn’t heating, the power diode might need to be replaced.
The power diode’s primary responsibility is to pass heat and block flow in opposing directions; if it’s not functioning the microwave can’t produce heat necessary to operate.
The high voltage capacitor might also have failed if you’re hearing a buzzing sound but not heat in the microwave.
This part is responsible for storing heat in your microwave; if it’s not functioning, your microwave can’t produce enough heat to operate properly.
A final problem with this microwave malfunction is the magnetron isn’t functioning.
The magnetron is a high-powered oscillator and is the main component of your microwave. If it isn’t oscillating properly, your microwave might buzz, but won’t produce heat.
This part should be checked cautiously, and may require a professional technician if it needs to be replaced.
Door Latch Assembly Failure
An issue with the door latch assembly might cause a malfunction.
Door latches are made of plastic or hooks which engage and disengage when you open and close the microwave door.
If the springs are damaged, the door won’t hinge and won’t close properly, which will prevent the microwave from operating.
To replace the door latch, you’ll disconnect your microwave and remove the inside door panel. Inspect the latch.
If it is damaged, you will have to replace it. Once replaced, reconnect your microwave and it should turn on/off like normal.
Faulty Microwave Door Switch
If the door switch isn’t functioning, your microwave won’t operate.
The door switch is a small switch that closes when you shut the microwave door. Like other fuses and wires, the door switch can also go bad over time.
To determine if this is the problem, you can use a multimeter to check if the switch is operable. If not, you’ll have to replace it in order for your microwave to function.
Microwave Turns on and Immediately Turns Off
Several problems can be causing your microwave to turn on, and off after a few seconds of operation. Some of these include
- A faulty door switch
- The main control board is failing
- Touchpad isn’t functioning (this isn’t common)
- The high voltage transformer has failed
- The thermoprotector may have tripped (safety to prevent overheating)
- The thermostat may be defective
Using a multimeter, you can check fuses, door switches, and other parts with electric currents, to check for circuity.
If any are faulty, you’ll need to replace them. If there’s a control board issue, this requires replacement of the control board.
Turntable Malfunctioning
If the turntable isn’t spinning, four parts can be causing this issue which are
- Drive bushing coupler
- Turntable guide
- Carousel cooking tray
- Carousel tray motor
The drive bushing coupler is a plastic piece that sits at the base of the microwave.
Check to see it isn’t broken or cracked; if it is, replacing this should resolve the problem.
The turntable guide is the round guide which sits below the turntable.
Check to see it’s properly aligned and adjust if needed. If it is broken, you’ll need to replace this part.
The carousel cooking tray should sit perfectly on top of the coupler and turntable guide. If it’s misaligned, this will result in the turntable not spinning.
If all parts are properly positioned above, the turntable carousel motor might have burnt out. You can use a multimeter to check it, and if it’s blown, it will need to be replaced.
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Sparks are Flying Inside the Microwave
With this problem, a utensil or piece of metal might be inside the microwave.
This can prevent it from working or shutting off entirely. If this is the case, wait several minutes and let the microwave cool down.
Open the door, remove the utensil/metal, and give it a few more minutes.
Try powering on the microwave once again to see if this resolves the problem.
Splattered food, especially grease or oil, can also cause your microwave to spark. Clean the inside to prevent this from happening.
If the above issues aren’t causing sparks, it might be a faulty part in the microwave.
If the power is concentrating to one area in your microwave, it’s likely an issue with the stirrer.
You might also check the high voltage diode with an ohm, to determine if it has to be replaced.
When to Call a Technician
If these resolutions fail, it might be time to call a technician.
Additionally, if there is complex wiring, electrical work, or other possible dangers, and moving pieces you simply don’t know how to work with, you might choose to call a repair tech as well.
It’s the safest way to resolve the problem, and they’ll troubleshoot your microwave to prevent further problems in the future.
If all else fails, or if your microwave is older than your 20-year old child, it might be time to upgrade to a new one.
So, consider the appliance’s age as well, if it simply keeps faltering on you. It might be time for a new one!
My whirpool microwave sometimes doesn’t work. If the interior light doesn’t come on it will not work. Sometimes if you hit the top of the oven light will come on and allow unit to work. I am thinking a bad door switch or control board, any ideas.