Microwave displays E20 and makes a sparking or arcing sound inside the cavity when running.

Safety first: Stop the microwave immediately and unplug it if you see sparks.

• Remove metal objects: Ensure no metal utensils, foil, or containers are inside the cavity.
• Inspect waveguide cover: Locate the mica waveguide cover on the side wall. If it is burnt, cracked, or has holes, replace it with a Telefunken-compatible waveguide cover.
• Clean the cavity: Thoroughly clean the interior with a mild detergent to remove grease and burnt food. Pay special attention to corners and around the waveguide cover.
• Touch-up paint (if minor): If small paint chips expose bare metal, use microwave-safe cavity touch-up paint to cover them. Allow to dry fully before use.
• Do not operate with damaged waveguide: If the metal behind the waveguide is burnt or pitted, professional service is required.