Your chances of getting a useful manual are slim. At least for me, a pile of
complex circuit drawings takes more time to deduce than its worth, you're
tossing 90 percent of it anyway. Unless you've got a tool changer, there's
not much to figure out.

Once your control box is empty and you've pulled the resolvers off the
servos (check you may get lucky and have encoders) you'll only have about 30
wires to figure out. Ten of them will be home and limit switches and the
common to them. nearly all machines use a special wire color for common just
tracing conduit runs will ID these inputs. You'll have three wires to the
spindle. Probably a spindle brake, often 120 VAC - note these work backward,
power holds them off. Maybe a power oiler and a couple other devices. Your
final group will be from your operator panel (which you probably won't use
but I do). Again, common is almost always one wire color. I put the rest of
the wires on an opto board and start pushing buttons and watching which
input lights on the opto board. You'll have to trace the wires from your MPG
(manual pulse generator) If you do have encoders, try to find the supplier
name and look up the wiring, otherwise white is often five volts common and
red or black +5volt. Get a logic probe and start watching which ones flick
on when. Encoders have been my most troublesome unit to figure out. You
should also have an Estop and Reset button, normally separate.

You will put some of the stuff you took out back in. Your servo power supply
should be fine. You can reuse the 5 volt and 24 volt power supplies, but I
normally don't. Re use one relay to make into your Estop reset or MCR
(master control relay)

I'm sure I missed a couple items, but you get the idea.

Karl