One of our mighty scans has an issue. when I enable strobing on with the shutter the shutter blade will gradially go off position until it starts tapping the side of the case ( very loud and annoying ). I have already ripped this fixture apart and tested it with my stand along DMX tester, and it still did this, so we can rule out any faulty DMX cables. I also checked the alan screws that keep the shutter on the axel of the stepper motor. They were tight. At this point I think it could be a bad stepper motor. Any thoughts?