Common Microwave Faults Published 13/03/2007
Microwave ovens are one of the most dangerous appliances to repair. When there's a fault, the high-voltage capacitor can store a potentially lethal charge for an indefinite period.
Specialised equipment and knowledge are needed to discharge it safely because simply shorting it out may cause it to explode. Any components or wiring connected to the capacitor may present the same danger.
Only the tasks suggested here can be performed safely.
Choose Your Fault For Likely Causes and Solutions:
Microwave Oven Appears Completely Inoperative:
- Faulty power supply - check mains lead, plug fuse and wiring, and mains outlet for faults.
- Time not set - built-in clock may need to be set in order for the oven to run. Follow manufacturer's instructions.
- Internal safety device faulty - stop using the unit immediately. Contact a qualified repairer.
- Door not closed - open and close again. If this fails, stop using the oven and contact a qualified repairer.
Food Heats Up But Interior Light is Out:
- Interior bulb faulty - replacing the light bulb involves working in dangerously close proximity to the capacitor and parts connected to it. Contact a qualified repairer.
Food Heats Unevenly and Turntable Doesn't Rotate:
- Dirt under turntable - remove and clean turntable and rotating turntable ring.
- Faulty coupling between motor and turntable - ensure the turntable is sitting correctly on holder.
- Turntable motor faulty - check the motor with a multimeter, and replace turntable motor if necessary.
Food Does Not Heat Up But Interior Light and Turntable Working:
- Magnetron and associated circuitry faulty - contact a qualified repairer.
- Incorrect power setting or cooking time selected - alter as necessary.
Food Takes Too Long to Cook:
- Control system or components associated with magnetron faulty - contact a qualified repairer.
Sparks Arcing in Cooking Chamber:
- Exposed metal edges - metal foil, food bag ties, containers and utensils should never be used in microwave ovens. Remove any metallic objects. Don't use crockery decorated with metallic paint or glazes.
- Carbonised food in cooking chamber or on door - clean cooking chamber and door thoroughly.
- Small holes in cavity lining - sand down area around burn spots and repair with specialist microwave interior paint.