Microwave runs but does not heat; display shows E3 after a few seconds of operation.

Critical safety warning: The high-voltage system in a microwave (transformer, capacitor, diode, magnetron) can store and generate lethal voltages. Do not attempt HV repairs unless you are trained and equipped to safely discharge the capacitor and follow proper procedures. For most users, contact a qualified appliance technician.

Basic user checks (no cabinet removal):

• 1. Confirm symptom: Place a microwave-safe cup of water inside and run for 1–2 minutes. If the turntable rotates and light is on but water remains cold and E3 appears, the issue is in the heating circuit.
• 2. Check power supply: Ensure the unit is plugged directly into a properly grounded outlet (no undersized extension cords). Low voltage can stress HV components.
• 3. Inspect for burning smell or noise: Listen for loud humming, buzzing, or arcing sounds. Note any burning odor and stop using the microwave immediately.

Technician-level checks (summary only):

• Remove cabinet and safely discharge the HV capacitor.
• Test the magnetron for continuity and shorts to chassis.
• Test the HV diode and capacitor with appropriate meter methods.
• Check transformer primary and secondary windings for continuity and signs of overheating.
• Replace defective HV components only with OEM-rated Midea parts.

If you are not experienced with high-voltage electronics, discontinue use and schedule professional service. Continuing to operate a microwave with a failed HV component can cause further damage or fire risk.