Yeah, I'm pretty sure it's mechanical. The control system seems to be working just fine. While it is connected through a parallel port I've not seen anything that leads me to believe it is electrical/electronic.
One shot oiler system seems to be pumping oil to all of the ways effectively. I can see it on the ways and where it drips off of things and onto the base of the mill in various places. Just lime my manual knee mill.
With the motor drives off the X axis moves freely using the knob on the end of the shaft. The other axes don't have anything to turn other than a bit of the end of the shaft that exits the encoder housing.
The set screws on the pulleys seem tight. That was one thing I checked on the Z axis earlier since I can get to that easily and couldn't figure out how it would have this significant asymmetric backlash problem like the X axis with the weight of the head loading the ball screw.
To check the other axes for freedom of movement I'll have to pull the motors and the belts to turn the pulley itself.
I will have to get someone to assist me to pull things apart since I can't take get table off unassisted.