Need Help!- Laserjet II stepper controller SI-7300a help

[fla_tim]

I have several Laserjet II and III printers that I want to salvage the steppers, power supply and drivers from. I have pulled one apart and have gotten the DC power supply to work. The stepper is connected to this board, into a SI-7300a driver. I have the datasheet and have found the four input lines for it. I thought I could just connect up and arduino and use the stepper.h library to run the stepper. But that did not work. The stepper just growls and and oscillates. If I pulse the four inputs slowly with the arduino, the stepper does rotate, but very roughly and slowly. I've searched the web and can't find any reference to what the SI wants to be fed. Does anyone have any experience with this setup and could get me pointed in the right direction? I feel that I'm close, but don't know where to go from here.

Thanks
Tim