That last point of Bob’s is important. That screw head can interfere with your motor when you go to position it. The motor ends up rocking on the head of the screw and that prevents you from getting things parallel. Replace it with a set screw to get rid of the head. There is apparently just enough variability in the belt lengths or other mechanical tolerance that the screw is either just barely out of the way or just barely too high. I had one axis the interfered and one that didn’t.
Wes, Southport NC
EXos2-GT PMC-8, iExos 100
ES ED 127, 10" LX200GPS+wedge, Astro-Tech 8" Newt, ETX-90, 60mm no-name guide scope ~ 260mm FL
Polemaster, Orion ST-80 and SAG, ZWO 290MM, D5300 astro modified
Nina, Bootcamped Mac Mini control computer, RDP to iMAC
110 amp hour lead acid deep discharge battery for field power
Electrical Engineer, Retired