I needed to open the box in order to ckean the leaser eye, the two guiding shafts of the laeser assembly, the bronze bearings on the right side of the eye assembly and the pinion shaft connected to the servo motor.
It was cleaned and lucricated !
The PROJECT was finished succesfully !
The "Jumping" and the "Stucking" that was happen before was elimenated.
Thanx again.