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HomeRepair HelpToshiba Microwave RepairToshiba Microwave is sparking or arcing Repair
Toshiba Microwave is sparking or arcing
If your Toshiba microwave is sparking or arcing, stop using it and inspect the oven before running another cycle. The most likely cause is a damaged or loose waveguide cover, also called a mica sheet. Replace the cover if it is burned, cracked, or will not stay in place. If the microwave is sparking in the cabinet area rather than inside the oven cavity, a shorted door switch, such as the primary, secondary, or monitor switch, may be responsible. Check for burn marks and test the switches with a multimeter. Arcing behind the waveguide cover can indicate a damaged magnetron, while a visibly burned high-voltage diode can also cause sparks, smoke, or a burning smell. Less common causes include a burned shelf support or chipped interior paint that exposes metal. Sand minor damaged paint carefully and apply microwave-safe touch-up paint. Any repair that requires removing the outer cabinet involves a high-voltage capacitor that can store a lethal charge even after the microwave is unplugged. Properly discharge the capacitor before interior work, or hire a qualified technician if you are not familiar with the procedure. Enter your Toshiba microwave model number to find the exact replacement part for your appliance.
01 - Toshiba Microwave Waveguide Cover
The waveguide cover might be damaged and arcing or burning. If this is the case or if the cover will not stay in place, replace it with a new one.
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02 - Toshiba Microwave Door Switch
If the microwave is sparking or arcing in the cabinet area, and not in the oven cavity, you will likely see smoke or there will be a burning smell. One of the appliance's door switches could have shorted and is causing the sparking or arcing. You should inspect each door switch for burn marks or damage and test the components with a multimeter to determine if any the door switches are malfunctioning.
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03 - Toshiba Microwave Magnetron
If the microwave is sparking or arcing behind the waveguide cover in the oven cavity, you will likely see smoke or there will be a burning smell. The appliance's magnetron is one of the components that could be damaged and causing the sparking or arcing. Inspect the magnetron for burn marks or damage and replace if necessary.
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04 - Toshiba Microwave Diode
If the microwave is sparking or arcing in the cabinet area, and not in the oven cavity, you will likely see smoke or there will be a burning smell. The appliance's diode is one of the components that could be damaged and causing the sparking or arcing. 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 direction..
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05 - Toshiba Microwave Shelf Support
Some microwave ovens will have cooking shelf supports on the interior walls. Inspect the shelf supports for any burnt spots or damage. If there are any burnt or damaged spots, replace with new supports as needed.
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06 - Toshiba Microwave Touch-Up Paint
The paint on the interior of the microwave might be chipped. If the paint is chipped, the interior metal will be exposed, causing the microwave to spark or arc. Check the interior of the microwave for any spots where the paint has chipped away. If there are any damaged spots, gently sand the compromised area and touch them up with microwave oven interior paint.
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Frequently Asked Questions
Why is my Toshiba microwave sparking inside?
What causes a Toshiba microwave to spark in the cabinet area?
Can I replace the Toshiba microwave waveguide cover myself?
Is it safe to test a Toshiba microwave magnetron or diode after it sparks?
How do I find the correct Toshiba microwave waveguide cover or door switch?
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