Microwave stops heating shortly after start and displays E02 or beeps continuously with E02 on the Telefunken display.

Safety first: Unplug the microwave. High voltage is present inside; do not touch the high-voltage capacitor or magnetron terminals.

• Check ventilation: Ensure the microwave has adequate clearance on all sides as specified in the Telefunken manual. Clean any dust or grease blocking the rear and side vents.
• Inspect cooling fan: Remove the outer cover. Locate the magnetron cooling fan (usually near the top rear). Spin the fan blades by hand; they should move freely. If seized, noisy, or not running during operation (test briefly with cover loosely in place if safe), replace the fan motor.
• Check thermal cutout (thermal fuse) on magnetron: Locate the small thermostat/thermal fuse clipped to the magnetron body or waveguide. With the unit unplugged, disconnect its wires and test for continuity. If open, replace with the exact temperature-rated Telefunken-compatible part.
• Inspect for burnt smell or discoloration: If the magnetron shows burn marks, cracks, or strong burnt odor, it may be failing and causing overheating. Replacement by a qualified technician is recommended.