Microwave will not start at all; display is lit but pressing START does nothing and no error code appears.

Safety: Unplug the microwave before any physical inspection.

User-level checks:

• Door closure: Open and firmly close the door. Ensure it latches with a solid click. Try pressing START while gently lifting or pushing on the door; if it starts intermittently, the door switches are suspect.
• Keypad test: Try other functions (e.g., setting the clock, using different cooking presets). If only START is unresponsive, the keypad may be faulty.
• Child lock: Check the user manual for child lock/"control lock" features. Some Electrolux models require holding a specific key (e.g., STOP/CLEAR) for several seconds to unlock.

Technician-level checks:

• Test the door interlock switches for proper operation with a multimeter.
• Inspect the door latch assembly for wear or misalignment.
• Test the START key on the membrane keypad for continuity.
• Check the main control board's start/relay drive circuit and replace the board if the relay does not energize when commanded.