The part(s) or condition(s) listed below for the symptom Microwave won't turn off are ordered from most likely to least likely to occur. Check or test each item, starting with the items at the top of the page.
Microwave Turntable Not Turning? Microwave Oven Troubleshooting
Microwave Not Working? Microwave Oven Troubleshooting
Microwave Not Heating? Microwave Oven Troubleshooting
Microwave Light Bulb Not Working? Microwave Oven Troubleshooting
Microwave Is Loud/Noisy? Microwave Oven Troubleshooting
Microwave Exhaust Fan Not Working? Microwave Oven Troubleshooting
Microwave Buttons Not Working? Microwave Oven Troubleshooting
Removing Microwave Trim - Tech Tips from Repair Clinic
Replace Microwave Charcoal Filter - Tech Tips from Repair Clinic
Boil Water in Your Microwave - Tech Tips from Repair Clinic
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Microwave Sparking/Arcing? Microwave Troubleshooting
Microwave Door Won't Open? Microwave Troubleshooting
Microwave Turns On By Itself? Microwave Troubleshooting
Microwave Display Not Working? Microwave Troubleshooting
Microwave Shuts Off After A Few Seconds? Microwave Troubleshooting
What Causes a Microwave to Spark and Arc?Most microwaves have three or four door switches. When the microwave door closes, the door switches actuate in sequence to ensure that the door is closed properly. If any of the door switches fail, the microwave will not start or heat. In some rare cases a door switch may short out and allow the fan to run even when the door is opened. To determine if any of the door switches are defective, use a multimeter to test each of the switches for continuity. If any of the door switches lack continuity, replace the switch. (Caution: The microwave oven can store thousands of volts of electricity in its high voltage capacitor, even after the microwave oven has been unplugged. Due to the potential for electric shock, it is extremely dangerous to replace the electronic components in a microwave. Only a licensed technician should replace a door switch.)
The cancel or off button on the user control and display board may not be activating. To determine if the control and display board is defective, try pressing each of the buttons on the control panel. If none of the buttons are responding correctly, replace the user control and display board.
The cancel or off button on the control panel may not be activating when it's pressed. To determine if the touchpad and control panel are defective, try pressing each of the buttons on the control panel. If some of the buttons respond correctly while others don’t, replace the touchpad and control panel.
The cancel or off button on the touchpad may not be activating. To determine if the touchpad is defective, try pressing each of the buttons on the control panel. If some of the buttons respond correctly while others don’t, replace the touchpad.
The main control board has relays that send power to several components to make the microwave work. If one or more of the relays or triacs short out, some of the components can keep running when the controls are turned off. (Caution: The microwave oven can store thousands of volts of electricity in its high voltage capacitor, even after the microwave oven has been unplugged. Due to the potential for electric shock, it is extremely dangerous to replace the electronic components in a microwave. Only a licensed technician should replace the main control board.)
The control board has relays that send power to several components to make the microwave work. If one or more of the relays or triacs short out, some of the components can keep running when the controls are turned off. While you can often replace just the control board, some microwave models sell control panels as an assembly with both the touchpad and control board included.
