Replacing a Kollmorgen 6410 Driver w/ less costly

I've had 2 Kollmorgen 6410 drivers (new old inventory) fail in the past year. My latest quote for one was $380. Just seems like A LOT of money for a stepper driver. I purchased a $35 DM860 driver and wired it in but not getting any movement in my stepper. Anyone have experience with this type of swap that could give advice? I have a Multicam SF series machine w/an upgraded RPD-24 controller. I'm not sure what the pulse widths are from the controller and if that may be an issue. The DM860 is putting out voltage to the stepper (not able to turn and I can hear it powered up) but it won't move when I start the homing sequence or try to move it manually. Any advice would be greatly appreciated! Thank you much.

I would expect this to work.
Check the wiring to the motor, be sure to have one coil between A+and A- and the other coil between B+ and B-.
It's easy to check if you have the two wires of one coil. First leave all disconnected from each other. Next rotate the motor by hand. It should rotate almost free.
Now connect two wires to each other leaving the other two disconnected. If the motor rotates heavy by hand, you found a coil ( the two connected wires )
Next step, verify the step connection. If you have a oscilloscope, that's the easy way to verify if you have pulses on the step connection between Pul+ and Pul- This input is direction sensitive. the signal needs to have positive pulses on the Pul+.
If you don't have a oscilloscope, take a LED and a resistor of 330Ohm ( anything between 220 and 2200 Ohm will do ) connect these in series and put that between the Pul+ and Pul- output
If the LED is lighted, give a command to move the axis. The intensity should change ( be less ) while the move command is active.
If the LED is not lighted at the first connection, give a move command and see if it lights up.
If it still doesn't light up, reverse the connection and try again.
If you get a change in brightness of the LED between not moving and moving the axis, then you have a good working output and I would expect the DM860 to work when you connect the Pul+ and Pul-
Next step is verify the DIR, connecting the LED you should be able to switch it On ( one direction ) and Off ( the other direction )
Give it a try and let us know the results. Or make some pictures of your connections.