Stepper problem

[eurikain]

Alright, I'm back after about an hour and a half of testing. Here is what I did:

1. Test the DB25 cable. All pins are through, no cross wires, and they work fine.
2. Wire only one motor, in parallel, with 1/8mcs and 2.7A (as close as I can get to 2.8).
   same problem. Same problem as before. Note that when not moving, the motors make weird sounds..., like a constant little quiet electrical noise, hard to describe.
3. Tried switching DIR and/or STEP active low setting. No change.

Here is what I haven't tried yet and will try tomorrow if you think it's worth it:

1. pins 4 and 8 in all four possible positions (00, 01, 10, 11).
2. switch one motor for the other (if same problem, it's not the motors, it's higher in the chain)
3. switch one driver for the other (if same problem, it's the board that's broken)
4. try another computer, who knows, the only thing I have changed since 2010 is this old computer. But it works fine, so I doubt it comes from there, but with those old guys, you never know.

So, if it's not the cable, not the PSU (already tested), not the motors, and not the drives, it's definitely the board.

What do you guys think ?