How To Troubleshoot A Microwave?
Microwaves contain a lot of sensitive and powerful electronic components which can fail over time. Troubleshooting a microwave will help you identify the causes of the issues you are experiencing and help you repair common issues with the machine.
Below we will look at the most common issues with microwaves and find out what may cause them.
9 Common Microwave Troubleshooting Problems
Microwave Shuts Off After a Few Seconds
Issues in the readings to your main control board, or shorts in the board itself will cause your microwave to shut off prematurely.
Broken or shorted touchpad controls can also cause a microwave to run for a few seconds before shutting off.
Microwaves contain a high-voltage transformer that charges the magnetron. If the microwave runs for a few seconds and shuts off the high-voltage transformer may be short-circuiting and will need professional repair.
If your microwave is running for a few seconds before it shuts off the thermostat of your microwave may be receiving a high-temperature reading. If your thermostat is faulty it will need to be replaced.
Microwave Exhaust Fan Doesn’t Work
If the exhaust fan is not working on the microwave the first issue to check would be the exhaust fan motor. Ensure the blades can move freely. You can also test the motor with a multimeter. If it fails either of these tests, it will need to be replaced.
If the exhaust fan tested fine, it may not be getting power. Test the output connections on the main control board to the exhaust fan to ensure it is sending power to the exhaust fan. If it is not powering the fan, you will need to replace the main control board.
A faulty thermostat can also cause the exhaust fan not to turn on. If the fan is in working order, and the main control board is supplying power, the thermostat could be defective.
Microwave Tray Won’t Turn or Stops Turning
The most common reason the turntable of your microwave will not turn is the turntable motor. Check the turntable motor with a multimeter to ensure the turntable motor is still operating.
Another common issue preventing the turntable from spinning is a worn or broken glass tray drive support. You will need to pull the glass tray drive coupling from the motor shaft to inspect for any damage. If it is damaged it will need to be replaced.
A worn or defective glass tray support can prevent your microwave tray from turning. Inspect the tray support for any damage and ensure it moves freely. If it doesn’t, replace the unit.
A faulty touchpad and control panel can be the cause of the microwave tray that will not stop turning. Check your touchpad and control panel with a multimeter to ensure it is not constantly sending power to the turntable motor.
If the touchpad and control panel are in working order, the main control board may be faulty or damaged and constantly sending power to the turntable motor.
Microwave Making Excessive Noise.
The exhaust motor is constantly turning off and on during the operation of the microwave which can cause the bearings found inside the motor to wear out and make a noise. If you hear any noise when you inspect the exhaust motor it will need to be replaced.
The microwave stirrer motor powers the metal blade that deflects the energy through your microwave. When this motor begins to go bad it will make a grinding sound. If you hear this coming from your microwave it will need to be replaced.
A bad or faulty bearing in the turntable motor can cause a noise in your microwave when it is running. If you hear any noise when inspecting the turntable motor it should be replaced.
Microwave Producing a Burning Smell
If you are experiencing a burning smell the waveguide cover may be damaged and causing arcing and or burning inside your microwave. If it is damaged or will not stay in place it will need to be replaced.
If the high-voltage capacitor begins to short out it will cause a burning smell. It can also cause your circuit breaker or inline fuse to trip.
When the diode in a microwave fails it will burn out and cause a burning smell. Only certified technicians should replace a faulty diode.
If the high-voltage transformer fails it will arc and cause your microwave to have a burning smell.
Microwave is Sparking or Arcing
If you are experiencing sparking or arcing in the microwave, check the waveguide cover for damage. If it becomes damaged or will not remain in place it will need to be exchanged for a new one.
Chipped paint on the interior of your microwave can expose metal and cause your microwave to spark when it is in operation. If there is any damage to the interior paint it can be touched up with microwave oven interior paint.
If your microwave is equipped with a cooking rack, it can become damaged or burnt and cause your microwave to spark. If there is any damage to the rack supports they will need to be replaced.
Microwave Door Stuck Closed
If the microwave door becomes stuck closed you will need to check the door hook. If the door hook is broken or damaged it will prevent the door from opening.
A broken or damaged door latch will also prevent the door from opening properly.
If the door spring is broken it will prevent the door from unlatching and opening.
Any damage to the door lever could prevent it from operating causing the door to remain closed.
The door button and button spring can become damaged or broken and prevent the door from being able to become unlatched and open.
A broken handle actuator between the door button and door latch assembly will prevent the door from operating and cause it to become stuck when it is closed.
Microwave is not Heating
If your microwave is not heating a burnt-out diode may be to blame. When the diode burns out it will prevent the magnetron from operating. A failed diode will be visibly burnt.
Microwaves have multiple door switches. If any of these switches fail it can prevent the microwave from starting or heating when it is running.
A burnt-out magnetron will prevent the high current DC power to generate the frequency needed to cook the food in the microwave.
If the high-voltage capacitor is burnt-out it will stop the entire high-voltage circuit from working and prevent your microwave from heating the food.
A high-voltage transformer will arc and have a burning smell if it fails. Without this voltage, the magnetron antenna cannot emit the energy needed to heat the food.
If a thermal fuse is blown it will stop the power to the microwave if it begins to overheat. The thermal fuse can’t be reset and must be replaced if it is blown.
If the microwave overheats a thermoprotector will cut off the power to the microwave. If it is tripped it will need to be replaced.
Microwave Light Doesn’t Work
The most common cause of the light not working is a burnt-out bulb. If the bulb is broken or burnt out it will need to be replaced.
If the bulb, socket, and wiring are fine the main control board may not be sending power to the lightbulb.
A damaged or burnt-out light socket will prevent the lightbulb from working. If it is damaged or burnt out it will need to be replaced.
Conclusion
Microwaves have a lot of electrical components that need to operate properly to make your microwave function. If the microwave is not heating or is producing sparks the cause of the problem will need to be addressed to bring it back to operating condition.