Updated to Blackbox after old my computer died. X and Y axis work fine but when I try to jog the Z axis either in the control software or with the keyboard (Page Up/Dn) the Z axis sometimes moves the correct direction and sometimes moves the opposite direction. I can press the "Page Up" key and the Z axis will move up once or twice then the next time it will move down, if I keep pushing "Page Up" it will reverse direction - I never know which way it will move. Any clue?
Yes - double check your wiring - you are looking for one wire which is only making an intermittent connection. Alex.
Agreed, either only 3 of the 4 wires are making contact, or the coil pairs are incorrectly identified. If motors did not come from us (or not recently) color code may differ from documentation