John,
I'll assume that you have everything wired up correctly. The sound of the steppers may not be very scientific but it is a good indicator of how the stepper is reacting to the provided signal.
1.What does the driver test look like? Are there a lot of spikes along the horizontal line?
2. In motor tuning, set the velocity to something slow like 10 ipm / 2 accel and jog the axis.
If they run.... Can you hear a tick-tick-tick sound or maybe thump-thump-thump ( sort of like a somebody hitting the
motors with a small mallet / hammer constantly)?
Can you give a better description of the sound thay make as "HICKUP doesn't help.
3. What drive and motor are you using? ( in your first post you have a variety of things that you were considering )
4. What kind of computer is it? Does it have onboard graphics? Laptop?
There are a number of things that can be creating the problem,but,I tend to agree with Hood and Jeff that's it's a signal quality problem / computer related. The pulse signal out of the PP should be a nice square wave. You need an osciliscope to see the signal and a decent scope at that. You also need to know what you are looking at when viewing the signal.
I have a Dell Optiplex GX520, fine for everything / good pc, but for running Mach it just plain sucks! Same goes for the Dell Latitude Laptop. Sometimes a change in the PP card or even a different graphics card will do the trick. Sometimes you can do everything you can think of and still no joy ( like optimization, removing installed software, modifying every setting know to man!, etc. So if the computer can't start off with a clean signal there is basicaly nothing you can do about it, and that includes trying to clean the signal up.
Option becomes using an external device like the SmoothStepper or get a different PC. I have done both!
So don't want to to drive you crazy and just suggest you start with the generated signal from the pc.
BTW, been there, done that, and it isn't fun!,
RICH