Why Does My Microwave Make a Loud Noise or Spark?
Sparking or suddenly loud? Here’s how to tell which microwave problem you’re dealing with.
Sparking (sometimes called arcing) and unusual loud noises are two different microwave problems with two different levels of urgency — and it’s worth knowing which one you’re dealing with.
Sparking or Arcing: Stop Using It
If you see sparks, flashes of light, or hear a crackling/popping sound while the microwave is running, turn it off and unplug it. This is almost always caused by metal (even a small trace, like the metallic trim on some dishware) or by a damaged wave guide cover, the small panel inside the cabinet that protects the magnetron.
Common Sparking Causes
- Metal, foil, or metallic-trimmed dishware placed inside
- A damaged or food-stained wave guide cover
- Food debris built up in one spot over time
A Loud Humming or Buzzing Noise
A louder-than-normal hum, especially one that seems to get louder over time, often points to a failing magnetron or a worn turntable motor, rather than a safety issue like sparking.
A New Rattling or Grinding Noise
This is usually mechanical, coming from the turntable motor, roller guide, or support ring, rather than the internal high-voltage components.
What You Can Safely Check
- Remove and clean the wave guide cover and turntable if visibly stained or damaged
- Double check nothing metallic went in with the dish
- Make sure the turntable ring and rollers are seated correctly
Typical Repair Cost Ranges
| Issue | Typical Cost Range |
|---|---|
| Wave guide cover replacement | $60 – $120 |
| Turntable motor replacement | $100 – $180 |
| Magnetron replacement | $200 – $400 |
These are general estimates based on typical industry pricing for this type of repair — your exact cost depends on the appliance’s make, model, and what’s actually wrong with it. Call for a free, no-obligation quote before any work begins.
Frequently Asked Questions
Microwave Sparking or Making Unusual Noise?
Our technicians can safely inspect and repair the issue.