604 retrofit

Our machine has ge encoders on it and I am trying to find information about them. I have been talking to Tom at dynomotion about using their snap amp and controller.
Can any one point me in the right direction on where I might find the info that I need.
Tag on the encoders are:
General Electric
3N1000FB103N4
52-83 S/N 81341
Same on encoder on the x, y, and z axis.
Before I purchase the snap amp does anyone have any info on the GE HI AK boards and amplifiers 90v dc. I have tried to see if they are useable but do not know how to test them. I do know that there is power coming in from a transformer but that is all I have been able to verify.

How old is the machine and control, if its in the range of 15-30 Jears the probaility is high that the encoders are TTL Quadruple and the amps have a +/- 10V input.