BFT garage door opener will not start; control unit display shows E01 immediately after power-up.

Safety first: Disconnect mains power at the breaker before opening the operator housing. High voltage is present inside BFT control units (e.g., ALENA, MERAK, RIGEL boards).

• Check incoming power: Verify that the dedicated circuit breaker is ON and supplying the correct voltage (typically 230 V AC in EU or 120 V AC in NA, depending on model). Use a multimeter at the line input terminals (L/N) of the BFT control board.
• Inspect the mains fuse: Locate the glass or cartridge fuse on the BFT control board (often labeled F1 or T2A/T3.15A). Remove and test for continuity. Replace only with the same rating and slow/fast-blow type as specified in the BFT manual.
• Check transformer connections: On models with a separate transformer, ensure primary and secondary wires are firmly seated in the terminals and show no signs of overheating or burning.
• Measure low-voltage output: With power restored (and covers in place where required), carefully measure the transformer secondary (often 24 V AC) at the control board. If no low-voltage output is present but mains is OK, the transformer is likely faulty.
• Inspect for board damage: Look for burnt tracks, bulged capacitors, or darkened areas around the power supply section. If present, the entire control board should be replaced rather than repaired in the field.

If you are not comfortable working around mains voltage, contact a qualified BFT technician.