Symptoms
How this shows up
- Visible sparks or arcing during operation
- Crackling sounds while heating
- Burn marks appearing on interior walls
Diagnosis
Likely causes, ranked
1. Metal object or foil inside the cavity
Even small metal fragments (twist ties, cutlery, decorative plate rims) can cause visible arcing.
2. Damaged waveguide cover
The mica/waveguide cover protects internal components; if it's burnt through or missing, exposed metal parts can spark.
3. Worn interior paint/enamel
Chipped enamel can expose the metal cavity wall underneath, which can arc during use.
Before you call
Safe checks you can do yourself
- Stop using the microwave immediately and unplug it
- Check for and remove any metal objects inside
- Do not attempt to run the microwave again until it's inspected - continued use risks further damage or fire
Call a technician if:
- Always, once metal objects are ruled out - a damaged waveguide cover or cavity needs professional replacement
Book a technician