I've spent a few hourson the problem and still a bit confused (admittedly that does take much
) and not got a solution yet.
I've tried to rewire the connections as suggested but think I did it correctly the first time as I saw the behaviour you mention when I tried to wired incorrectly.
The motors data sheet gives the connections as black-green for one coil and red-blue for the other.
The RJ11 give connections 2 to 5 so I've connected as 2-red, 3-black, 4-green , 5-blue. Does that seem right?
With this got the RA motor moving at the higher speeds seeming fine. The single step does seem to work, but the noise comming from the motors isn't great - a like durr with a brief pause every second. Changing the current make the noise louder but also heats up the motor much quicker so not really an option.
The DEC motor won't move at all on a single step, but will move at higher speeds.
I'm starting to wonder if it that the RJ11 connections as they are not the best.
I'm not sure what else to try as the connection was only the bit that I've done.
Any suggestions?