Microwave runs but does not heat; E03 appears on the display after a few seconds.

Critical safety warning: The high-voltage section of a microwave (transformer, capacitor, diode, magnetron) can be lethal. Do not attempt this repair unless you are trained and equipped to safely discharge the capacitor.

• Basic user checks only: Confirm that the unit is not in demo mode and that you are using a standard heating program. Try a different power level and time setting.
• Visual inspection (for trained persons): With the unit unplugged and the capacitor safely discharged, inspect the high-voltage capacitor and diode for bulging, burning, or cracking. Check the transformer for burnt smell or discoloration.
• Component testing: Use a suitable meter to test the high-voltage diode and capacitor according to service manual procedures. Replace any component that tests out of specification with Zanussi-approved parts.
• Magnetron check: Inspect the magnetron for burn marks, cracks, or arcing around the antenna. If suspected shorted or open, replace the magnetron.

Due to the danger involved, most users should contact a Zanussi-authorized technician for E03 faults.