Hello from new member and problem with drivers and motors

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.

Welcome to the forum! I too am from Manchester in the UK live in Canada now for over 30 years.

Since you have an old oscilloscope I would first place you scope leads on the Step and Direction outputs of the controller on the Z and A axis pins to make sure that you have the correct signals being produced from the breakout board. Not knowing your controller board I would assume 0 to 5 volts maybe you should see a change in voltage from high to low on the direction pin and then positive going pulses for the Step pin. This would prove once and for all whether you have damaged the controller board or not.

Hi,
those XHC motion controls are now quite old and not supported by XHC any longer.

Buy yourself an Ethernet SmoothStepper and suitable breakout board, they are supported and more importantly are still developing with regards to Mach4....and is highly recommend over Mach3.

Craig

Thanks for your reply. I did try this but didn't get get anything I could interpret. What you suggest makes sense. If I can get a meaningful reading from one of the motors that is working then I will know what to look for. Mysterious that the Z axis red light is on. Maybe the motion control board is damaged.

Thanks for your advice. Well ... if the motion control board and/or drivers are damaged then I would want to replace with something better.

As it was mentioned before, why wouldn’t you use oscilloscope to determine if controller is bad?
If you post schematic or good photos someone would direct you how to hook it up and what to expect on your oscilloscope.
How many axis on the controller? If you burned one axis output and you have like 4 or 6 axis controller you could change settings in Mach3 and use other axis output to substitute the damaged one or two…
Try to use differential probes or differential inputs on your oscilloscope that way you don’t have to track where the ground is…