Microwave runs but does not heat; display shows E03 after a few seconds.

Safety first: Unplug the microwave. The high-voltage section (transformer, capacitor, diode, magnetron) can store lethal charge. Do not access internal components unless you are trained and equipped to safely discharge capacitors.

• Confirm symptom: Place a cup of water inside and run on full power for 1–2 minutes. If the turntable and light work but the water remains cold and E03 appears, the issue is likely in the high-voltage circuit.
• Basic external checks only: Verify that the power outlet is delivering correct voltage and that the microwave is not on an overloaded extension lead. Try a different outlet.
• Listen for abnormal sounds: A loud humming, buzzing, or crackling from inside the cabinet when heating is attempted can indicate a failing transformer, capacitor, or diode.
• Professional service recommended: High-voltage diagnostics require disassembly, capacitor discharge, and component testing with appropriate meters. A Hansa-authorized technician should test the transformer, HV capacitor, HV diode, and magnetron, and replace the failed part.

Warning: Do not continue to run the microwave with E03 present; this can cause further damage or fire risk.