Ok, I'm back and running now so I want to close the loop here with what I learned. I tried everything suggested above and also some stuff that the service tech suggested over the phone, but nothing was working. The home switches were correctly switching from zero to one as could be observed from the parameter screen, the motor cables checked out ok (although they're old so likely need replacing), the ball screws spun freely, I cleaned all the chips from under the way covers, cleaned the black brush dust from the motor, and still I got the same fault. During my trouble shooting process I moved the X axis all the way to the right. This is when I discovered the one thing about the fault that was driving me nuts. During the zero return sequence from this table position the X axis would move the table all the way back to the left like it is supposed to do, then it would hit the home switch and give me the fault code. So to me it appeared that the motor was capable of moving, but I didn't understand what was happening once it hit the home switch.
I called in the service tech...he said it was an interesting problem that he hadn't encountered before. he turned some parameter off so he could jog the axis without having the zero return. he could jog the axis to the left, but everytime he tried jogging it to the right he got the fault. His trouble shooting was simple, but effective. He checked the motor cables then swapped the X and Y axis drives. The issue followed the drive. Mystery solved for me.
I wanted to write as much as I knee here as to document it for others to learn from.
One last tis bit of info. I used the A axis drive for the X axis. The tech told me I couldn't do that but he didn't know why. I don't use the A axis so I really wanted to steal this drive. I carefully went through each component on the drive board and learned that the only difference was two resistors. I un soldered them from the X axis board, soldered them onto the A axis board and everything is currently running good.
I'm still curious as to why the drive went bad in the first place. I would assume if the cables were bad that I would blow a fuse. If anyone has any thoughts about that please share them.