Newb retrofit question

Hello, 
     I have acquired an older (mid 90's) industrial cnc plasma table. I got everything working and had the control doing whatever preset shapes were installed on the old DNC 2.8 controller before it was taken apart and moved. What I want to do is retrofit a different control to this machine using as much of the existing parts as possible. I'm new to cnc other than what i've read on 3d printers and whatever info I've picked up fooling with this plasma. 
So far I'm thinking of going with Linux CNC as the controller.
I *think I need some kind of control card to talk to the servos. mesa? (do I need just 1 or one for each servo?) 
I'm not positive I need a power supply yet. I believe I can take the one out of the old DNC control box and reuse it. Suggestions? 

I have no idea about height control yet. I don't believe this has height control so I may want to integrate that. 

I want to be able to program custom shapes for cutting. Pretty much what most of the newer plasma cutters seem to do. So I'm open to suggestions on which direction to go. 





 

First you need to figure out what type of control the drives require, most probably +-10V, but that has to be confirmed before buying anything.
If they do work, i would not change them.
Do you have any schematics ?

Linuxcnc would be a good solution to retain as much as you can but as Tommy said the drive type is what is required. If they are analog +-10v controlled, the Mesa 7i77 plus maybe some additional cards for extra IO. Or the newer 7i97 ethernet card. But lets visit that later when the drives are understood.

The Mesa THCAD card allows you to read the torch voltage. This  lets Linuxcnc perform the THC function for you so there is no need for an external THC
If you don't have a Z axis motor or torch lifter, you may need to add a servo or stepper motor to the torch lifter.

The linuxcnc QTplasmac config, does have some basic conversational shape capability.

I'll see if I can find anything on the voltage. The book disappeared a while back, but from what I remember it mostly had info about how to manual program G code in it. No schematics really.
The servo motors look to be CMC model: MT2630 if that helps anything. I'll take a look at the stuff a little closer tomorrow when I get some time.

Alright I finally got time to look at the box of parts I have more. Doesn't look like there are any books.
The pictures I'm attaching are of the encoder I guess it is (it says something about signal voltage). Along with the gear reducer and model of the servo.
Is there anywhere else to look for the information? I did search online for more information on the servo but didn't see whether or not it was the +-10volts.

 

The encoders are normall A/B/Z differential, so can be wired directly to Mesa boards as they do work with 5V supply.
No drive pictures?
Edit:
Are there tacho on the motors?