Hello from new member and problem with drivers and motors

[Woodchopper]

I have a CNC machine built in Spain. It has a very heavy, rigid frame made of welded steel, Mach 3 motion card WXHC MKX-IV (USB not parallel port). I have the Mach 3 controller software. I have been cutting violin plates and other bits and pieces with reasonable success. However, for some jobs I need a 4th axis (rotary) .. which I bought from CNCpart2018 on Ebay. I have been able to identify the micro-stepper driver and download a manual. The motor is just a generic stepper with 4 wires. I have not been able to get this to work at all. The motor locks when powered up but will not rotate. I believe all the settings and wiring are correct. In an attempts to get to the bottom of this problem I connected the new motor to the Z axis driver and the (separately) the Z axis motor to the A axis driver. Now when I power up the Z axis driver has the red light on continuously and no longer works. From searches this seems to mean something is wrong with the input voltage but it looks OK to me.

If any parts are not working then I must replace them but don't want to do that before I have reasonable certainty that they are are fault. Can anyone suggest any diagnostics that would help here? I am in Manchester - is there anyone local who might help? I can offer in return access to some woodworking machinery and a Myford Super 7 lathe.

[m_c]

Have you tried restoring the wiring back to how it was originally?

[Woodchopper]

Have you tried restoring the wiring back to how it was originally?

I have put all the wiring for the Z axis back exactly as it was. I always take a photo before changing anything. The rotary A axis was not connected to anything previously. The connections are not exactly rocket science - Only 3 wires from controller and 4 to the motor. It is easy to determine which coil is which. If A+ and A- are the wrong way round then the motor should still turn but maybe the wrong direction. Obviously you can't mix A and B.

[m_c]

It's kind of hard to give exact advise without knowing what drives are fitted.
What drives are they?

It could be the drive has died, but I'd be wanting to know why.
Are the Z and A steppers comparable sizes?
Did you let the drives fully power down before changing any wiring?