Microwave stops heating shortly after start and displays E2; fan and light may still operate.

Safety first: Unplug the microwave. Do not operate with covers removed. High voltage inside can be lethal. Only a trained technician should work near the magnetron, transformer, capacitor, and HV wiring.

User-level checks:

• Check ventilation: Ensure the microwave has at least the clearance specified in the Proline manual (typically 10 cm at sides and rear). Remove any items blocking the side, rear, or top vents.
• Clean vents: Use a vacuum or soft brush to remove dust and grease from external vents.
• Listen for the cooling fan: Start a short heating cycle with a cup of water. You should hear a steady fan noise. If the fan is unusually loud, scraping, or silent, the cooling fan motor may be failing.

For a technician / advanced DIY:

• Remove the cabinet and inspect the magnetron cooling fan for free rotation and power supply during operation.
• Test the magnetron thermostat / thermal cut-out for continuity. Replace if open when at room temperature.
• Inspect the magnetron fins and airflow channels for heavy dust/grease buildup and clean carefully.