Retrofiting an old big milling machine

I have a plan to use the machine as is without mechanical modification with linuxcnc.
After that and if it works i will add 2 more servos to X & Y and keep the existing motor for Z to make it full cnc.
I have already 2 1.8kw ac servos.

Hello again.
I have removed a scale from machine and it has 6 wires+1 chasis ground
It says on the label 15V and 40um.
It is made in Bulgaria 1992.
Inside has an IC TL084CN with 5 multiturn trimmers and 2 small electrolytic caps.
The small pcb in scale has no solder mask is only tinned.
How i can identify that the wires are?

That's a quad op-amp, so the trimmers are probably gain adjustment.
Given that it's all analogue on the board, I would expect that the 6 wires are two differential outputs and 2 power inputs. From the op-amp data sheet you can probably work out which wires are power supply with a multimeter just by checking continuity.

www.ti.com/lit/ds/symlink/tl084.pdf

Ok i got it how to find VCC & GND wires.
I also have this schematic if helps for the signals..

What is the 7.5V & U3 rep shown in schematic?
Is this scale 1Vpp ?

It looks like sin/cos voltage on U1 and U2 and possibly an index on U3.

It also seems that you might need to supply both 15V and 7.5V.

That said, Uref Usin and Ucos looks a lot like a resolver. Does the scale appear to be optical, or is is like the Accupin system?

I will give VCC & GND 15VDC and i will see the output on oscilloscope