Stepper motor help...STM5776

[SweetAs]

Hi Paulus,

Yes all checked manually. I've just taken the belt off again and checked the following..

No discernable play in the shaft of the stepper motor.
Pulley grub screw is tight
Moved the Y axis back and forth with the pulley to stepper belt off, everything felt smooth, checked the bearings as best I could but they look fine. They are 6001Z and the shaft is supported twice, either side of the belt pulley at both ends if that makes sense.
Ill take the main Y belts off in a second and see how the axis moves without any resistance at all.
Couplings adjacent to the motor seem fine, no play in them.

Here is a pic of the set up....