If your Litton microwave is not working, not turning on, or seems dead even though it has power, start with the line fuse. A blown line fuse stops the microwave from starting, but the electrical problem that caused it must also be corrected or the replacement fuse may blow again. Next, inspect the switch holder behind the control panel. If it is damaged or misaligned, the door switches may not actuate when the door closes, leaving the microwave not working. The main control board can fail, but it is rarely the cause, so check the more common parts first. An overheated or open thermostat can cut voltage to the high-voltage components, while a blown thermal fuse can shut the microwave down after overheating. Also verify that the wall outlet has power by testing it with another appliance, then check the home breaker or fuse. Enter your model number to find the exact Litton replacement part for your microwave. Any repair that requires opening the outer cabinet, including fuse, thermostat, or control board replacement, involves a high-voltage capacitor that can store a lethal charge after unplugging. Proper capacitor discharge is required, so use a qualified technician if you are not familiar with the procedure.
01 - Litton Microwave Line Fuse
If too much current passes through the microwave circuitry, the line fuse will blow. If the line fuse blows, the microwave won’t start. To determine if the line fuse is at fault, use a multimeter to test it for continuity. If the fuse does not have continuity, replace it. In addition, you should investigate and resolve the problem that caused the fuse to blow. If you don’t resolve the underlying issue, the new fuse will blow too. (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, i...t is extremely dangerous to replace the electronic components in a microwave. Only a licensed technician should replace the line fuse.)
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The microwave switch holder is the component that houses the door switches behind the control panel. If the switch holder is damaged or misaligned, one of more switches may not be actuated when the microwave door is closed, resulting in the microwave not working. 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.
The main control board might be defective. However, this is rarely the case. Control boards are often misdiagnosed—check all of the more commonly defective parts. If you have determined that all of the other components are working properly,replace the main control board. (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.)
If the microwave overheats, the thermostat trips to cut off voltage to the microwave. If the thermostat is shorted open, it may not allow voltage to reach the high voltage components. To determine if the thermostat is at fault, use a multimeter to test it for electrical continuity. If the thermostat does not have continuity, and it cannot be reset, replace it.
The electrical outlet may not be getting power. To determine if the outlet is getting power, try plugging something else into the outlet. If the outlet is not getting power, check the home circuit breakers or fuses.
Highly Likely
06 - Litton Microwave Thermal Fuse
The thermal fuse cuts off power to the microwave if the microwave overheats. To determine if the thermal fuse has blown, use a multimeter to test it for continuity. If the fuse does not have continuity, replace it. The thermal fuse cannot be reset—if the fuse is blown, it must be replaced. (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 thermal fuse.)
Since the control board controls the voltage being sent to all of the microwave's components, a defective board could be responsible for a microwave not working. However, this is rarely the case. Control boards are often misdiagnosed—check all of the more commonly defective parts. If you have determined that all of the other components are working properly, replace the control board.