I've been struggling with this issue and can't seem to figure out what's happening and don't know what to do. While running a job on my cnc router, randomly one of the motors will stop working. There is no noise coming from the motor, so I don't believe it's stalling. The DRO in Mach3 will continue to count, but again the motor doesn't move. Once I restart Mach3 the issue usually goes away, until again I run g-code. This doesn't seem to be a problem while jogging around. I haven't seen any errors pop up when this happens. I've ran a few smaller jobs successfully, so this problem has seemed somewhat random, making it even more difficult to troubleshoot.

My setup:
CNCRP Pro Machine
Mach3 2010 Screenset
Nema 34 motors
PMDX-126 BOB
PMDX-134
G203V Drivers
ESS
Huanyang 2.2kw Spindle & VFD

I've rechecked wiring and everything looks fine. I don't believe it's a mechanical issue (I've put loctite on all my pulleys), mainly because it jogs fine once Mach3 is restarted. Any help would be greatly appreciated!

Sounds like a communication problem with the  one of the G203V.

I'm coming to that conclusion, but the big question is where is that communication problem.  So far I've unplugged all my motors and still getting the red light.  I've also taken out my drivers and tested them by swapping them around and trying them one by one on different axis and still getting faults.  So, this tells me it's probably not a driver issue. 

I've also checked my power supply and she is steady as could be, so I don't believe this is the problem either.  So it could be a setting in Mach3, Ethernet Smoothstepper, PMDX-126, or one of the ribbon cables going between these.  Big issue is, how do I troubleshoot these.  I can't think of a way to test them.

I don't think that there are any settings that can cause the drive to fault.
It would appear that either the drive is overheating, or you have some bad connections to the motors?
Do you have the drives mounted to heatsinks and fans on them?

The drivers were on a heatsink and had fans in the controller cabinet. Plus the machine is in the garage which is 30 degrees. Add to that, the drives often fault fairly quickly when the code starts to run I wouldnt guess it would be overheating. I also touch them after and they are cool to the touch. How long would it take for them to overheat?

At this moment I don't even have motors connected to the drives and the drives are faulting. So it can't be any motor connectors or cables. Since it's happening to all the drives on different axis I don't think it's the drives.

I don't get how the drives could fault with no current going through them since the motors aren't connected.

Was there ever a resolution to this problem? I am having the same issue.

There was/has not been.  I have been pulled away from further troubleshooting this issue due to work, but hoping to jump back on it in the next couple of weeks.  I tried for hours and tried all methods and settings to troubleshoot it too.  I simplified everything as much as possible, still with no luck.  Gecko was nice enough to let me send the drives back so they could test them, but they all came back as fine.  My biggest disappoint is the lack luster customer service I've received from PMDX, especially after everything great I've read about them (the reason I purchased their products!).  After I asked if their product could at all be the culprit I never heard anything back.  Very disappointed!  

So I've purchased another power supply, a parallel port, and CNC4PC card.  I'm going to replace each of the items in hopes that one of them is the reason for the issues because after that I literally have nothing to replace on the skeleton controller.  So once I get some time I'm going to jump back on it.  

I can't swear the this is the answer but worth a try.  I just had a similar problem and resolved it by an official Ford diagnostic technique. The wiggle test. Wiggle all connectors. Hope it's that easy for you.

Astro Pop