need help Bridgeport Series 1 CNC

I have a Bridgeport Series 1 CNC and it quit on me yesterday it started with the x axis would not move. It will move if its down around 3 ipm. so i started looking on the internet and found it could be the drive transistors. so i checked them a found one bad. I changed it and found x was still not working so i changed the whole block with z and z still worked fine I switched smd boards z for x and still not working. the only thing is the acc board but i don't know if that could be it.
I'm running a machine master interface board to mach 3 using original motors and drives.

any ideas would greatly be appreciated.

thanks,

Troy