Any experience or software for Control Techniques FNC4? Wha do I replace it with?

[uli12us]

You don't need to change the motors, changing the drivers is enough.
60V and 3/6Amps isn't really expensive.
The Gecko 320X or leadshine DCS810 each with 80V 20Apeak are more than capable for this.
But the encoder of the motors must have a TTL output, single ended is enough.