If you have saved the wiring harness as well, you need to isolate the wiring between the motor and the speed control board. You will find that there is forward, reverse and variable speed available. It all depends on whether there is a wiring diagram available, and the type of programmer the machine uses. Early machines were rotary mechanical types, later ones are all digital, and a bit more complex. By a process of deduction, and some VERY CAREFUL experimentation, it should be possible to see where the feeds need to go to produce forward, reverse, and probably a couple of spin speeds, or even infinitely available spin. Time to learn some basic electrickery!