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Tappan Microwave turns on by itself

If your Tappan microwave turns on by itself, first determine whether the vent fan is running or the microwave is actually starting a cooking cycle. On an over-the-range microwave, the vent fan may turn on automatically during stovetop cooking when its thermostat senses excess heat, then shut off after the microwave cools. If the touchpad is working correctly and the microwave is starting without a command, the main control board is the most likely cause and may need replacement. A faulty interlock switch can also send the wrong signal, while a damaged or misaligned switch holder may prevent the door switches from engaging properly. Less commonly, intermittent contact between circuits in the touchpad and control panel, or a defective touchpad, can cause the microwave to turn on by itself. Test door switches with a multimeter and inspect the switch holder if you are comfortable removing the control panel. Opening the outer cabinet exposes a high-voltage capacitor that can store a lethal charge even after the microwave is unplugged. It must be properly discharged before interior work, so use a qualified technician if you are not familiar with that procedure. Enter your model number to find the exact Tappan replacement part for your microwave.

01 - Tappan Microwave Main Control Board

First, make sure that the touchpad is working properly. If the touchpad is working properly, the main control board is likely at fault. If the control board is defective, replace it.
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Top Solution

02 - Microwave cooling down during stovetop cooking

Most over-the-range microwaves have a vent fan thermostat that will turn the vent fan on automatically to keep the microwave from overheating. The fan will shut off after the microwave cools back down.
Highly Likely

03 - Tappan Microwave Interlock Switch

A microwave that turns on by itself can be caused by a malfunctioning interlock switch. You can use a multimeter to test the interlock switches to determine if they are functioning appropriately and replace if necessary.
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Common

04 - Tappan Microwave Switch Holder

The microwave switch holder is the component that houses the door switches behind the control panel. If the switch holder is damaged or misaligned, the switches may not be properly engaged which could cause the microwave to turn on by itself. You will need to uninstall the control panel and inspect the switch holder to confirm it is in good condition and secured properly. Replace the switch holder with a new one if necessary.
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Common

05 - Tappan Microwave Touchpad and Control Panel

It’s possible that the touchpad and control panel button circuits are coming into contact with each other intermittently which could cause the microwave to turn on by itself. If this happens, the touchpad and control panel will need to be replaced.
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Less Common

06 - Tappan Microwave Touchpad

It’s possible that the touchpad button circuits are coming into contact with each other intermittently which could cause the microwave to turn on by itself. If this happens, the touchpad will need to be replaced.
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Less Common

Frequently Asked Questions

Why does my Tappan microwave turn on by itself?
Why does my over-the-range microwave fan turn on by itself?
How do I test a Tappan microwave interlock switch or door switch?
Can a Tappan microwave touchpad or control panel cause it to turn on by itself?
How do I find the correct Tappan microwave part for this repair?

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