Symptoms
- Visible sparks, flashes, or arcing light inside during operation
- Crackling or popping sound
- May be localized to one spot on the wall or turntable support
- Possible small burn marks on the interior wall
Likely causes
- CommonMetal object or metallic trim in the microwaveMetal reflects microwaves and creates sparks; this includes twist ties, foil, or gold-rimmed dishes.
- CommonDamaged interior wall coating exposing metal underneathChips or scratches in the wave guide cover or wall paint can arc.
- PossibleDamaged wave guide coverThis small cover near the magnetron opening can burn or crack and needs replacement.
- PossibleEmpty or near-empty microwave runningRunning a microwave with nothing to absorb the energy can cause arcing at the wave guide.
What to do
- Stop the microwave immediately and unplug it if you see sparking.
- Open the door and remove any metal items, twist ties, foil, or metallic-trimmed dishware.
- Inspect the interior walls and the small wave guide cover (usually on a side or top wall) for scorch marks, holes, or bubbling.
- Never run the microwave empty; always have food or a microwave-safe cup of water inside when testing.
- If you find a damaged wave guide cover, this is a simple, inexpensive part to replace yourself once you have the correct model part.
- If the interior wall itself is damaged or you can't find a cause, don't use the microwave until a technician inspects it.
Tools and parts
- Screwdriver (for wave guide cover swap)
Microwave wave guide coverSearch: “microwave wave guide cover replacement”
When to call a pro
If you can't find an obvious cause like metal or a damaged wave guide cover, have a technician inspect the interior and magnetron.
Safety
Use caution
Stop using the microwave immediately if it sparks; continued use can damage the unit or start a fire.