In this step, we will finish adjusting the belt tension. Please read the instructions first, your belt might have proper tension set already, then there is no need for additional screw adjustment.
⬢First, slightly release all the screws holding the motor. Otherwise, the "tensioner" won't work (the motor must be able to move).
⬢Using ball-end Allen key start tightening the screw on the rear side of the X-end-motor, but after each turn or two check the tension in the belt.
⬢For the optimal performance, the belt must feel stiff if you pinch it with your fingers. Move the extruder all the way to the X-end-idler and try the belt tension in the middle of the X-axis.
⬢When you achieve an optimal tension, please tighten the screws up again.
In case you are experiencing X-axis failures during calibration or skipped layers in the X direction, adjust this screw accordingly. Tightening the screw stretches the belt. Releasing the screw has the opposite effect. And don't forget to release the screws on the motor first :)