Ade,

You might find that repairing it is cost prohibitive. If I was in your shoes, I'd consider getting a replacement Servo Drive / Motor (400 W) from a range of different suppliers and changing out the Z axis.

The Y Axis motor is difficult to work with (space). The X is fairly easy but if it was me, Id want to keep X and Y the same motors. The Z axis is obviously very different and the motor bracket is fairly easy to modify. You can easily take a plate and modify and then once your machine runs, mill a new one or give me a drawing and I can do one for you.

Charl