Microwave display shows E04 and the unit will not start; sometimes accompanied by a loud humming or buzzing before shutdown.

Safety warning: Unplug the microwave. Inverter-based microwaves use high-frequency high-voltage circuits that are extremely dangerous. Do not attempt to probe or repair the inverter board yourself.

Basic checks:

• 1. Power cycle: Disconnect power for 10 minutes to allow internal protection circuits to reset. Plug back in and test with a cup of water.
• 2. Ventilation and load: Ensure vents are clear and you are not running the unit empty. Overheating can trigger inverter protection.
• 3. Listen for abnormal noise: If you hear loud buzzing or arcing sounds when it tries to start, stop using the microwave immediately.

Next steps: An E04 code almost always indicates a failed inverter board or magnetron. Both are high-voltage components and should be diagnosed and replaced by a qualified technician familiar with Vida inverter microwaves.