Help with selecting hardware for CNC retrofit

Hello!

I am newbie on CNC machines but somehow I managed to buy a huge an old plasma CNC machine  (Vanad Kompakt 1500 from 2001 with MEFI 836 CNC control). It works now but it was no electrical documentation for it so my plan is to exchange control system for it.
As it is now I'd would like to keep the servos, tachometers, encoders to keep the costs down.
It has double PMDC motors for X-axis, one PMDC for Y-axis. The Z:axis has a simple car wiper motor.
The PMDC motors is 24VDC,5A,80W and have separate tachometers and encoders (TTL Quadrature).
(The plasmaburner is not working so I'm planning to rebuild the machine to a milling machine so I will mount a spindle motor later on.)
Right now my choice is to go for LinuxCNC and a Mesa card like the 7i96E/7i96 but I am not sure what motor driver card I should use..
Would really appreciate any tip on hardware that I should go for.

Thanks in advance 
Pär
 

If the drives are working first find out how they are controled, chances are they use analog +-10V, so for that a Mesa 7i97 should do, or a combo of one Mesa 5i25 or 6i25 or 7i92 with a Mesa 7i77.
Do a search for Esab UltraRex there are several retrofits here on the forum to get an idea of what is involved.
Having schematics saves a lot of time.

Thank you for quick reply!
Ok I will try the measure them up and see if I can figure out how the drives are wired and functions and hopefully be able to use them as well.

Take a lot of pictures and upload them here on the forum (not on 3rd party sites), we are pretty good at figuring things out from pictures, especially connectors, boards, tags, etc.

I've taken some photos of the motor drivers and luckily when remove the clips it was labeled on the the card so that made it a little bit easier 
Started the machine and a found out that one of the X-axis drivers isn't working so it only drives with one motor at the time..
One of the fuses on the driver card is blown and it seems to be some shortage that I haven't been able to find which component that is faulty so I guess a need to find a motor driver card for that motor. Grateful for any tip for a good driver card.

The encoder cables are connected directly to the PC and the tacho are wired to the driver card.
When measuring "SYMETRICKY VSTUP + & - " (see picture Drivercard labels) I get -3VDC to 3VDC. I have only managed to manually jog the motors and there is a speed settings in manual mode that goes from 0-3, so I'm not sure if it possible to drive the motors with -10V:10V.
Maybe it's speed limited in manual mode and that is why it only is -3V/3V?
Have a Raspberry pi 4 with LinuxCNC on so I've thinking of buying 7i92M and a 7i77. Is that an ok setup or should I get hold of a PC with parallel port and go with 5i25 and a 7i77?
 

Symetricky Vstup =  symmetrical input.
How exactly did you measure the input?