Microwave display shows E04 and unit will not start; sometimes accompanied by a loud hum or tripping breaker.

Safety warning: This fault involves the high-voltage system. Do not attempt internal repairs unless you are qualified. Risk of electric shock and fire.

Basic user checks:

• Unplug the microwave and leave it disconnected.
• Check the wall outlet and circuit breaker; if the breaker trips only when this microwave is used, the unit likely has an internal short.
• Inspect the power cord for visible damage or burns. Do not use the appliance if any damage is found.

Professional diagnosis steps (for reference):

• Discharge the high-voltage capacitor safely.
• Test the capacitor for shorts and capacitance value.
• Check the high-voltage diode for forward conduction and reverse blocking.
• Inspect the magnetron for visible cracks, burns, or shorts to chassis.
• Measure transformer windings for shorts or open circuits.

Recommendation: Because multiple high-voltage parts may be involved and incorrect repair can be dangerous, contact a Candy-authorized technician. Keep the unit unplugged until inspected.