Stay with the the servo-motor, it's a good solution.
If the relay on the DNC-board still switches the motor you can try shifting the plug,
supposing the original motor controller with his LED-display is still in place. The display electronic works independently from the motor electronic
without any connection.(the great gap on the controller board shows it)
The relay on DNC not only switches the motor (with 2 contacts parallel) but the third contact switches the 10 V for the display (parallel with the Hand / CNC switch.
The switch-output for the motor is doubled on X61 on pin 1/2 in and 8/9, this enables by shifting the plug by one position to have display in CNC-mode or not.
Because mains and 10 V are on the same connector be ware when working on and check triple with the picture of plug X61.