These are relatively complex machines for their time. Lots of gearing there....gearbox for the spindle drive that is shifted using logic and small motors to make the changes.
Generally they are either in gear or not, shifting is supervised by cams and micro switches to tell the logic when it has engaged the selected gear combination.
Vertical spindle has potential to be noisy using bevel gearing to redirect the drive to the vertical....
Spindles also have their own set of concerns. There are no replaceable inner or outer bearing races on either the horizontal or vertical spindles...Needle rollers run directly on the ID of the quill and the OD. of the
spindle....wear is accounted for with oversized rollers (gauged in microns)
Vertical axis does a fair bit of work. Might need some work if the machine was run doing work that included peck drilling cycles....lots of mass to move up and down....Thrust bearing and screw could be potential
areas that might need some attention.
Deckel NC's also have a nasty habit of having trouble with gauling on the vertical ways....Run the table to full height (- Z) Then have a look at the inside face of the box ways on the non operators side viewed from underneath the
vertical slide.....Any heavy scratches or grooves tell the tail of potential problems...Can be repaired but requires some skill and disassembly. Will run for a long time with this problem and still make good parts.
The basic machines are quite robust. Things i have outlined above are mechanical and most can be addressed (if even needed) by someone with good mechanical skills .
Would say that noisy gears could be repaired, but likely cost prohibitive!
Spindles generally are good. Unless coolant or rain water has entered the spindles they can be brought to full function by overhaul. (disassembly, cleaning and assembled using the proper grease and adjustment.
The biggest gremlin there is the control. Like ALL Deckel NC's the machine is dead if the control is not 100% functional....
The electronics in general are robust and can be repaired (discrete components on the boards), and some exchange support is available form FPS or Singer in Germany at a price....
The overall design is quite flexible and adaptable..Suitable for lots of differing tasks... Slow by modern comparisons in both max RPM, rapids or processing speed of the control.
I own 4 FP-NC's and i wouldn't trade them for any current wiz bang modern "box" , but that is because for me the architecture is perfect for my work....That , i believe has got to be the first and overriding question that needs answering..
Cheers Ross