Y-axis motor problem not rotating smoothly

[Objectprint 0]

Hey guys,

I have a little problem with my ultimaker 2 and from one day to the other the y axis motor doesn't seem to rotate correctly?! so when the printer is off and you try moving the extruder head around the axis you can not move the extruder head to the back so to its home position. Cables are all connected. I think it could be the axis controller but it happens when the printer is on and the cables are out of that axis?!?

[DidierKlein 729]

With the machine off you cannot move the head in Y ?

When it's off the motors are off, they should rotate freely

[Objectprint 0]

No I can't! which means the motor itself is the problem and needs replacement?!