Replace the Worn Y-Axis Belt

1. Power off the A1 mini and disconnect the power cable. 2. Remove the bottom cover of the printer base to access the Y-axis motor and belt assembly. 3. Loosen the tensioner screws completely to release the old belt. 4. Remove the damaged belt, noting the original routing path. 5. Install the new, official Bambu Lab Y-axis belt, ensuring the teeth face the pulley and the belt is correctly seated in the idler and drive pulleys. 6. Reinstall the bottom cover. 7. Power on the printer and perform the full automatic calibration via the printer menu to ensure the new belt is properly tensioned and synchronized.