Cooling Fan Problem
If your Magic Chef microwave is overheating, there may be a problem with the cooling fan. The cooling fan keeps the magnetron -- the part of the microwave that sends out radio waves -- from overheating. If the magnetron overheats, it can ruin the electrical components in the microwave. Thus, if the cooling fan fails to keep the magnetron cool, the heat trips a circuit in the microwave and the microwave stops working until the magnetron cools down again.
Intermittent Overheating
Some Magic Chef microwaves have an automatic reset switch on the thermal overload device (TOD). The TOD cuts off the power if the magnetron gets too hot. If there's an automatic reset switch, the microwave will begin working again once the magnetron cools down. This makes the microwave work intermittently -- it stops working, overheats, cools down and starts working again.
Warning
If your Magic Chef microwave is an over-the-range model, don't adjust the exhaust fan unless you read the instructions and understand exactly what you're doing. If you aren't careful, you can cause the part of the exhaust fan that cools the magnetron to point away from its target, which will cause the microwave to experience intermittent overheating problems. When you adjust the exhaust fan's position, you must adjust the cooling fan so it continues to cool the magnetron.
No Reset Setting
Some Magic Chef microwave ovens don't have a reset setting. This means that if the microwave oven overheats, it won't function anymore unless your technician opens the microwave and manually resets the TOD. For this reason, it's important to check regularly that the cooling fan is blowing while the microwave is on. Contact your technician if the microwave doesn't appear to be cooling itself properly.