Fanuc servo motor and servo drive retrofit with linuxcnc and mesa card

Hello, i buyed a Seiki Mori MV40B machine(year1989) that has fanuc controller and servo motors(lost prgogram because of battery). i attach pictures from cabinet and motor plate. I'm trying to retrofit with linuxcnc and mesa boards. Anyone that could give advice about this, i need to change de driver? (fanuc says it's servo amplifier) i can controll with mesa board? There is a lot of information about the posibility of controlling axis with mesa board, spindle with some change of the spindle encoder.... but i haven't find something that is suitable for me.I want to keep de servo motors if possible (because of the cost of new one) and make adaptations to make small costing retrofit, but if is not possible, i want to know if there is o solution for retrofiting with smallest cost . 

It might be possible depending on the exact servo drive model
Some FANUC drive of that vintage are Analog +-10V controlled

Can you find the actual drive model?
 

A20b-1003-0090/05A and A16B-1200-0800/06Ai have found also a pdf manual, hope to put as attach