Quote Originally Posted by Doddy View Post
If these are wired in a unipolar manner - which is sounds as though they are... you will need to isolate the centre taps. I appreciate the buggeration that comes with this - and recognise that at this time you're probably trying to keep the machine in a recoverable format (normally I'd just cut/isolate the cable at the stepper), but I understand you may want to be a bit more circumspect. the centre tap will be either to ground or to +V and it'll be causing problems for the driver - certainly your described behaviour I can imagine with the centre taps connected.
So just to recap the X Axis stepper now uses the 2 pairs of wires that have the highest resistance.

Today I thought while I would do the same with the other two steppers starting with the Y axis. Disconnected the 4 leads from the driver and the resistance on each pair is 2.4 ohm. Opened up the cover at the stepper end and to my surprise there were 6 wires connected (X Axis only had 4) I measured the resitance to find the correct two pairs to use and am now lost. Two pairs (brown/orange and red/yellow) have a resistance of 1.8 ohm and the two purple have a resistance of 0.4. I should say at this point the manufacturer of the stepper is unknown. I don't yet know where the purple wires go but all the unused wires that go to the control cabinet from the umbilical have been disconnected and isolated (at least I thought they had). I will trace the 2 purple wires tomorrow or Saturday.