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HomeRepair HelpGibson Microwave RepairGibson Microwave not heating Repair
Gibson Microwave not heating
If your Gibson microwave is not heating, not heating food, or runs but doesn’t heat, the high-voltage diode is the most likely cause. The diode converts transformer output to the high-voltage DC power the magnetron needs, and a burned diode may show visible damage or fail a proper continuity test. Next, check the door switch, since a failed primary, secondary, or monitor switch can prevent the microwave from starting or heating even when it has power. A failed magnetron can also stop heating and must be replaced rather than repaired. Other possible causes include an open thermostat, a defective high-voltage capacitor, or a failed high-voltage transformer. A transformer failure may also cause arcing or a burning smell. Any repair that requires opening the outer cabinet, including work on the magnetron, high-voltage diode, high-voltage capacitor, or high-voltage transformer, is hazardous because the capacitor can store a lethal charge even after the microwave is unplugged. It must be properly discharged before interior work, and a qualified technician should handle the repair if you are not familiar with capacitor discharge procedures. Enter your model number to find the exact replacement part for your Gibson microwave.
01 - Gibson Microwave Diode
The diode converts the A/C power output of the transformer to D/C, doubling the voltage to nearly 5,000 volts. This high voltage powers the magnetron to heat the food. If the diode burns out, the magnetron won’t receive enough voltage to operate, preventing the microwave from heating. When the diode fails, it is often visibly burned out. Inspect the diode and if the diode is burned out, replace it. If inspecting the diode proves inconclusive, test it with a multimeter that uses a 9-volt battery or put a 9-volt battery in series with the diode. When the leads are reversed, the diode should only have continuity in one direct...
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02 - Gibson Microwave Door Switch
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 fails, the microwave will not start or heat. 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 does not have continuity, replace it. (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 extremel...
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03 - Gibson Microwave Magnetron
The magnetron uses high voltage, high current DC power to generate the microwave frequency that cooks the food. If the magnetron burns out, the microwave won’t heat. The magnetron is not repairable—if the magnetron is burned out, you must replace it. (Warning: The microwave oven can store a lethal amount of electricity in its high voltage capacitor, even after the microwave oven has been unplugged. Due to the high running voltage and the potential for electric shock, it is extremely dangerous to replace the electronic components in a microwave. Only a licensed technician should replace the magnetron.)
Highly Likely
04 - Gibson Microwave Thermostat
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.
Highly Likely
05 - Gibson Microwave High Voltage Capacitor
The high voltage capacitor works with the high voltage diode to convert the output of the transformer to DC voltage and to double the output voltage. If the capacitor is burned out, the entire high voltage circuit will stop working properly, and the microwave won’t heat. To determine if the high voltage capacitor is defective, use a VOM meter with a capacitance testing capability. (“Warning: The microwave oven can store a lethal amount of electricity in its high voltage capacitor, even after the microwave oven has been unplugged. Due to the high running voltage and the potential for electric shock, it is extremely dangerou...
Common
06 - Gibson Microwave High Voltage Transformer
Microwave ovens produce a very high voltage in order to power the magnetron antenna, which emits the energy that cooks the food. When a high voltage transformer fails, it will usually arc and have a burning smell. (Warning: The microwave oven can store a lethal amount of electricity in its high voltage capacitor, even after the microwave oven has been unplugged. Due to the high running voltage and the potential for electric shock, it is extremely dangerous to replace the electronic components in a microwave. Only a licensed technician should replace the high voltage transformer.)
Common
07 - Gibson 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 doesn’t 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.)
Less Common
Frequently Asked Questions
Why is my Gibson microwave not heating even though it runs?
How do I test a Gibson microwave door switch or thermostat?
Can I replace the diode or magnetron in a Gibson microwave myself?
What should I check if my Gibson microwave is not working but has power?
How do I find the correct Gibson microwave replacement part?