Hi Hood, I've checked the port assignment, and swapped the pin assignment for step and direction, and it has no effect. I changed the active state and same result. I checked all wiring from the motors to the drivers, and from the BOB to the drivers, and all appears correct. When the motors run in one direction, the correct one I assume, they run smoothly, while in the opposite direction they are rough and jerky!
Many Thanks, Denis.