How to Fix a Sparking Microwave

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Prevent sparks while you’re cooking with our troubleshooting guide
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If you notice flashes or sparks that look like lightning in your microwave, then there’s an issue with the appliance or with what you’re cooking. Before you use your microwave more, diagnosing and fixing the issue can keep you safe and prevent more damage to your microwave. Keep reading, and we’ll walk you through what’s causing your microwave to spark and what issues you’re able to safely fix on your own.

Why is my microwave sparking?

  • Metal in the microwave is the most common cause of sparking.
  • A damaged waveguide cover can also cause sparks.
  • Built-up food and grease in the microwave can also sometimes cause sparking.
Section 1 of 3:

Microwave Sparking Causes and Fixes

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  1. The microwaves that cook food aren’t able to pass through metal, so they bounce off and create sparking or “arcing” inside of your appliance. This normally happens if you accidentally leave silverware or aluminum foil in your microwave, or if use cookware that has metal trim. [1]
    • How to Fix: Take out any food and dishware and check for any scraps of foil or metal pieces, and make sure you’re using dishes that are labeled “microwave-safe” when you’re heating up your food. Other materials you should avoid using in your microwave include: [2]
      • Gold and silver
      • Recycled paper
      • Pewter
      • Skewers
      • Twist ties
      • Foil liners
  2. Moisture in your food helps absorb the microwaves so your food heats evenly. When you’re cooking food that’s really dry or has a small portion, the microwaves bounce back onto the appliance components and could cause sparks or flares. [3]
    • How to Fix: Sprinkle your food with a few spoonfuls of water before cooking it to help absorb more of the microwaves and prevent sparking. [4]
      • To help retain even more moisture, place a microwave cover over your food to trap the steam.
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  3. When food and grease build up inside of your microwave, they can start to carbonize after multiple cooking cycles. Over time, these spots can turn into hot spots in your microwave that create sparks and arcing.
    • How to Fix: Clean the inside of your microwave.
      • Fill a microwave-safe bowl with 2 tablespoons (30 ml) of white vinegar and 2 cups (470 ml) of water. For a fresh smell, replace the vinegar with juice from 1 lemon instead.
      • Put the bowl in your microwave and run it for 5 minutes to help soften the residue.
      • Let the bowl sit for 5 minutes before taking it out and wiping the inside out with a microfiber cloth. [5]
      • If your microwave still sparks when you run it, stop it immediately. You can still use the same cleaning solution, but it’ll just take a little extra elbow grease to scrub stuck-on residue.
  4. If your microwave has a rack, the coating on the outside can start to wear away and expose metal underneath. Similarly, if the shelf supports are damaged or bent, it can expose bare metal where sparking happens. [6]
    • Take out the rack and inspect it for any chips or damage. Then, look at the shelf supports on the sides of the microwave’s interior to see if they’re bent, broken, or deformed.
    • How to Fix: Replace the microwave rack or shelf supports. If the rack that came with your microwave is broken or has exposed metal, you may be able to order an exact replacement from the manufacturer or a universal microwave stand . If the shelf supports are broken:
      • Order rack supports for your microwave.
      • Pry the old support pegs out with a screwdriver.
      • Straighten out any dents or raised areas.
      • Push the new supports in their place. [7]
  5. The stirrer is a metal spinning piece with a cover piece at the top of the appliance that helps distribute the microwaves evenly. If the cover is broken or has damage, you may see sparking inside the microwave near the top. [8]
    • How to Fix: Install a new stirrer cover .
      • Use a flathead screwdriver to pry out the pegs holding the circular cover from the top inner wall of your microwave.
      • Take the disc-shaped metal stirrer out of the old cover and place it inside the new cover.
      • Reattach the stirrer cover to your microwave and push the pegs back into place. [9]
  6. The waveguide cover sits over the opening where microwaves come into the appliance, and it’s usually a rectangular piece found on the interior right side of your microwave. If the cover gets damaged, then food can get inside or metal can be exposed, which can lead to sparks. [10]
    • How to Fix: Insert a new waveguide cover .
      • Unplug your microwave when you replace a waveguide cover to help prevent damage or electrical shock.
      • Take out the tray and roller from the bottom of the microwave.
      • Then, use your fingernails or a screwdriver to pry the old waveguide cover off.
      • Press the new cover in its place until it's secure.
  7. The interior paint normally covers the metal parts inside your microwave. If you accidentally chip or scratch the coating, then sparks will start to appear and radiate from the same spot each time you run your microwave. [11]
    • How to Fix: Apply touch-up paint to a chipped interior. Touch-up paint works on spots that are about the size of a quarter or smaller.
      • Clean any spots around the chipped paint with soapy water and then pat it dry with a lint-free cloth.
      • Use fine-grit sandpaper to sand any burnt areas to the bare metal, and wipe it clean.
      • Apply the touch-up paint in a thin coat and let it dry for 5 minutes.
      • Then, apply another coat to completely cover the spot. [12]
      • Wait 24 hours after applying touch-up paint to use your microwave again.
  8. The door switch is a component that only lets your microwave run when the door is completely closed. If the switch has corroded terminals or if it has any damage, then it can create sparking near the door when your microwave runs.
    • You may also notice a burning smell if the door switch is the cause of the microwave sparking.
    • How to Fix: Hire a technician to replace a faulty door switch. Microwaves contain high voltage even after you unplug them, so leave internal repairs to a professional. A repair technician will:
      • Unscrew and disconnect the control panel from your microwave to access the wiring and door switch behind it.
      • They’ll then remove the old door switch, replace it, and reconnect all the pieces together again. [13]
  9. The diode in your microwave connects the electrical components together so your microwave runs properly. If the diode is starting to go bad or is losing power, then sparking may appear randomly inside of your microwave. [14]
    • A bad diode may also cause your microwave to stop working completely.
    • How to Fix: Get a professional to repair a busted diode. The technician will:
      • Unscrew and remove the control panel to access the electrical system.
      • Discharge the capacitor with an insulated screwdriver so there’s no risk of electric shock.
      • Then, they will unscrew the old diode and replace it with a functioning part. [15]
  10. The magnetron is the main piece that creates the microwaves that cook your food. Normally, the magnetron distributes the microwaves evenly throughout the appliance, but it can create hot spots that start sparking when it starts to fail. [16]
    • How to Fix: Have your microwave serviced for a bad magnetron. The repair person will:
      • Unscrew the back panel of your microwave to access all of the internal pieces.
      • After discharging the capacitor, they will remove the old magnetron from your microwave and install a new functioning part. [17]
  11. Gevorg Grigorian, an appliance repair technician says, “The cost of replacing a microwave is usually lower than if you were to repair a component… So most people end up…get[ting] a new one.”
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Section 2 of 3:

Is it safe to use a microwave that is sparking?

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  1. The sparks in your microwave are normally caused by hot spots that are overheating. Over time, the sparks can damage your microwave and make it unsafe to use. If you see sparks, try to find the cause and make repairs right away.
Section 3 of 3:

How to Care for Your Microwave

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  1. To stay on top of food buildup and stop it from forming, add cleaning your microwave to your weekly to-do list. [18]
  2. Use microwave-safe dishes to heat food. Whenever you want to cook or reheat food, make sure the dishes or containers that you’re using are labeled as “microwave-safe.” This ensures that your microwave won’t spark or get damaged.
  3. Take a moment each week to look over your microwave and check it for any chips, dents, or exposed metal. If you notice any damage that you’re able to fix on your own, then do the repairs before using your microwave again.
    • If your microwave has issues that you can’t troubleshoot on your own, then hire a professional technician.
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      Tips

      • If you notice sparks or arcing inside of your microwave, stop it immediately to prevent any damage to the appliance.
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      Warnings

      • Unplug your microwave whenever you’re cleaning or doing repairs for added safety.
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      • Avoid taking apart and repairing the internal parts of a microwave on your own because it can still contain a high voltage even after it’s been unplugged. Leave repairs to a professional technician so you stay safe.
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      References

      1. ↑ https://www.lg.com/ae/support/products/documents/MFL55318536.pdf
      2. ↑ https://www.whirlpool.com/content/dam/global/documents/201706/useandcareguide-w11083577-revb.pdf
      3. ↑ https://www.lg.com/ae/support/products/documents/MFL55318536.pdf
      4. ↑ https://www.lg.com/ae/support/products/documents/MFL55318536.pdf
      5. ↑ https://www.bonappetit.com/story/how-to-clean-microwave
      6. ↑ https://youtu.be/VGGO_7l6Gts?t=54
      7. ↑ https://youtu.be/VGGO_7l6Gts?t=63
      8. ↑ https://danmarcappliance.com/microwave-repair/what-could-be-causing-your-microwave-starts-sparking/
      9. ↑ https://youtu.be/tssKKLOpO7E?t=4
      1. ↑ https://youtu.be/2_lrTfRTk5c?t=18
      2. ↑ https://youtu.be/VGGO_7l6Gts?t=37
      3. ↑ https://youtu.be/Y-2q2hi_gvk?t=33
      4. ↑ https://youtu.be/qRlO-kUesw4?t=35
      5. ↑ https://danmarcappliance.com/microwave-repair/what-could-be-causing-your-microwave-starts-sparking/
      6. ↑ https://www.youtube.com/watch?v=GbDQr1evGG8
      7. ↑ https://www.whirlpool.com/content/dam/global/documents/201706/useandcareguide-w11083577-revb.pdf
      8. ↑ https://youtu.be/o3-IKLa_ajI?t=62
      9. ↑ https://www.bonappetit.com/story/how-to-clean-microwave

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