[Solved] Feels like a silly question: step motor wire pin out?  

RE:

So, I came in to shake my head in embarassment.

The back story: I built the clone from parts from a couple of other printers I'd found second-hand.I'd wired up the motors, and I had to flip a couple of wires (the inner pair) to get the X-axis to turn. That meant the order was RGBK at the motor, and RBGK at the board. But that same order wasn't working for the other motors. I beat my head against it for a while, until I finally just re-wired the other motors to see if it would help. And it did...

The back-back story. Most of the parts came from one printer in particular. But I built the X-axis about a year ago, before starting grad school... and that motor was from a different printer. And the pin out was different. RGBK at both ends.

All motors are working correctly now, and the X-axis motor was replaced with one that matched the rest of the motor set.

So, lessons learned:

-Technician error can not be underestimated. I've been a tech in a variety of fields, and half the time I end up hunting down human error, and not tech specs.

-Different step motors can have different pin-outs. After this particular experiment, I will say that having a drawer full of loose step-motors can lead to issues. Nothing catastrophic or horrible, and probably nothing that will fry your board, but the motors won't move, they'll just jitter. Make sure you're using motors that came from the same source. (Could be same printer, could be same manufacturer, pick whatever label is most specific.) That said, the wires do seem to be matched up in pairs... the outer pair, and the inner pair.