Before joining the pieces of the LR2, I tested the software of the MiniRambo card and the connections with the motors.
Apparently everything works correctly, except for the motor of the X axis that produces a rare noise, and barely moves. I have recorded a video to show you the problem:
I have also tried to change this motor whit another one, and the result is similar.
Is it possible that the X motor wires are misplaced?
By the way, the rest of the motors (Y, Z) work fine!