Wire Edm

I have an OLD Japax wire EDM, that I traded a techincal school out of.
I've thought about retrofitting it, but don't know the first thing
about the electronics inside of one of those. It works fine, but
somehow the box that switches between manual and tape operation was
lost in transit (they disconnected it before I got there). I had
considered rewiring the stepper motors to run on a PC, and let the
machine think it was in manual mode, but I now believe it has to sense
the gap between the wire and part to get the right feedrate. I would
be interested in any info you guys could give, or would gladly take
offers to buy it. It takes up a lot of room to not be working, and I'm
still saving for a new Tormach ;) Pics are posted at
www.clymermachine.com

Thanks
Nate