Oven Convection Fan Not Working? 6 Causes and What to Do
A convection fan that will not spin is usually a failed fan motor, a seized blade, a door switch or a relay on the control board. Here is how to narrow it down.
Read the guide
Why is my microwave sparking?
A microwave sparks when energy jumps to a metal edge or a burned spot inside the cavity. The most common causes are metal in the oven, a greasy or burned waveguide cover, chipped paint that exposes bare metal, a damaged rack support, and, less often, a failing diode or magnetron. Food splatter that burns can also spark.
Sparking is different from a microwave that runs but stays cold. For that, see microwave oven not heating up but runs.
Our appliance repair Mountain View CA technicians fix countertop, over-the-range and built-in microwaves from GE, Whirlpool, Samsung, LG, Panasonic, Sharp, Bosch and Thermador.
What should you do the moment it sparks?
- Press Stop or open the door. The microwave shuts off when the door opens.
- Watch for flames. If something is burning inside, keep the door closed and unplug it or turn off the breaker. The fire will run out of air.
- Let it cool. Then look inside with a flashlight.
- Find the spot. Look for a black mark, a burned hole or chipped paint.
What are the 5 most common causes?
1. Metal inside
Foil, twist ties, a fork, a gold-rimmed plate or a takeout box with a metal handle will spark. Remove it and the problem stops. Check under the turntable too.
2. Dirty or burned waveguide cover
The waveguide cover is the small panel on the side wall or ceiling. Grease and food splatter soak into it. Over time it burns and turns black, and the burned spot sparks. Wipe it gently. If it is burned through, it needs replacing. It is one of the cheapest microwave repairs.
3. Chipped cavity paint
Many microwaves have a painted steel cavity. When the paint chips, the bare metal edge can arc. Small chips can be touched up with microwave cavity paint. Large chips or rust usually mean replacement.
4. Damaged rack supports or turntable parts
Convection microwaves with metal racks have plastic supports that keep the rack off the walls. If one breaks, the rack touches metal and sparks.
5. Diode, capacitor or magnetron problem
If sparking happens with an empty, clean cavity, or you hear buzzing with a burning smell from the vents, the high-voltage parts may be failing. These parts hold a dangerous charge even when unplugged. Do not open the cabinet.
Still sparking with nothing metal inside? Stop using it and call for microwave repair in Mountain View.
How do you test after a spark?
Clean the inside, remove anything metal, then heat one cup of water for one minute on high. Stand back and watch through the door. If you see no sparks and the water gets hot, the cause was likely metal or splatter. If it sparks again, stop using the microwave and have it checked.
Never run a microwave empty to test it. With nothing to absorb the energy, it can damage the magnetron.
Repair or replace a sparking microwave?
Repair makes sense when the cause is a waveguide cover, a rack support or a small paint chip, and for over-the-range or built-in models that cost more to replace. Replace a low-cost countertop microwave if the magnetron has failed or the cavity is rusted. Most microwave repairs in Mountain View cost about $120 to $350.
| Cause | Usual fix |
|---|---|
| Metal or foil | Remove it, no repair needed |
| Burned waveguide cover | Replace the cover |
| Small paint chip | Touch up with cavity paint |
| Broken rack support | Replace the support |
| Diode or magnetron | Technician repair, or replace a cheap unit |
How can you stop it from happening again?
- Cover food with a microwave-safe lid or paper towel so it does not splatter.
- Wipe the inside, including the waveguide cover, once a week.
- Steam-clean baked-on food with a bowl of water and lemon instead of scraping.
- Check plates and mugs for metal trim before heating.
Other common repairs we see in Mountain View
If another appliance is giving you trouble, these guides can help: oven not preheating all the way, fridge water and ice dispenser not working, microwave oven not heating up but runs, and washing machine repair for washers that leak, stall or will not spin.
Frequently asked questions
Is it safe to use a microwave after it sparks?
Stop using it until you find the cause. If the sparking came from foil or a metal rim, remove it and test with a cup of water. If it sparks again with nothing metal inside, do not use it until it is repaired.
What is the waveguide cover in a microwave?
It is a small panel, usually mica or cardboard-like, on the inside wall or ceiling. It covers the opening where microwaves enter the cavity. Grease on it can burn and spark.
Can I paint over chipped paint inside a microwave?
Only with paint made for microwave cavities, and only on small chips. Regular paint can burn. If the chips are large or the metal is rusted, replacing the microwave is often the safer choice.
How much does microwave repair cost in Mountain View?
Most microwave repairs in Mountain View cost about $120 to $350 with parts and labor. A waveguide cover is near the low end. Over-the-range models cost more to remove and reinstall.
