This is my first post. I am a violin maker working in Manchester UK and have started using CNC for milling parts and accessories. The machine I have was built by someone in Spain several years ago by a guy who operates gigantic CNC controlled lathes as his day job and custom builds machinery as an extra job.

My machine is not very big but is super robust with a massively heavy welded steel frame. The breakout board is labelled WX HC MKX-IV MACH3 MOTION CARD. It connects via USB not parallel port. All was working fine until I tried to add a 4th axis - a rotary arrangement assigned to the A axis. The software in Mach3 MK II. The drivers and stepper motors are unbranded.

When I first wired up the A axis motor it's possible that I connected the VCC and ground to a motor output. This would be because of trying to do it with the driver in a place where I could actually see the connection labels without a mirror. So it's not impossible that I damaged the micro-stepper driver. Anyway .. I am now as certain as I can be that it is correctly wired. The motor locks when powered up but I can't persuade it to rotate. All the Mach 3 settings have been checked. The guy who built the machine sent me an XML file with appropriate settings and I have checked these out in multiple forums and web searches and I do not think anything has been missed. The builder has made various suggestions but he does not speak English and my Spanish is not up discussing such technical matters. However, I can go back top him with specific questions.

In an attempt to isolate the problem I connected the A axis driver to the Z axis driver and also tried using the Z axis driver for the rotary axis motor. Neither worked. I photographed the wiring before so I could be sure to get it back as it was. Now the Z axis has a red light that stays on continuously and doesn't work.

I have a good multimeter and an old oscilloscope. Can anyone suggest diagnostic procedures to get to the bottom of this? If I have to replace parts then so be it but don't like that as a diagnostic strategy. Any advice would be greatly appreciated. Even better would be if the is a member who is nearby who could be physically present.