Not out of the woods yet.

Dell Vostro, newish, USB keyboard and mouse - never any problems with those.
All excess SW stripped off machine, no network, etc etc.
RC combo removed from SmoothStepper.
Latest driver V2.08.02 installed and checked.

Still getting 'The smoothstepper has not communicated for a while' error message and Mach hanging.
Help ...

Cheers

Not sure if it will help or not but some people reported that unchecking the power option in your USB hub helped, see pic.
Hood

You also have to check the other things in your power profile, screen saver, HD shutdown, etc. On Win7 there is an advanced option in the Power Profile to disable the USB Selective Suspend, that is the place to change it rather than on each root hub (the way you do it in XP).

Hi Hood and Jeff

You also have to check the other things in your power profile, screen saver, HD shutdown, etc. On Win7 there is an advanced option in the Power Profile to disable the USB Selective Suspend, that is the place to change it rather than on each root hub (the way you do it in XP).

I will check, but I doubt that is the problem. My reasons include:
I was reading a plain text file when it hung, so the system was quite active.
The load due to Mach is under 5% of capacity, so no problems there.
The USB port was very active of course, so I doubt that the system would have tried to power it down.
The hang was identical to previous failures: Mach was in the same infinite loop as before.
I recovered the system by unpluggging the USB cable.
No hub anyhow, and WinXP SP4, but no matter.

I would be fairly sure it's a software problem caused by noise and not handled by the driver and Mach.

I will try a big earth link between the SS and the PC chassis, run parallel to the USB cable. Should not be needed as everything is earthed (tight wiring requirements in Oz), and that does raise the possibility of an earth loop, but it's worth trying.

Cheers

The USB port was very active of course, so I doubt that the system would have tried to power it down.

The USB device can be put into Selective Suspend if there is a 1ms lull in USB traffic from the device. (It might be 3ms I don't recall exactly, but it just a handful of ms.) I have done a lot of research on this and found cases where it would happen to some people with their mouse (what a PITA that would be.)

Hi Jeff

The USB device can be put into Selective Suspend if there is a 1ms lull in USB traffic from the device. (It might be 3ms I don't recall exactly, but it just a handful of ms.) I have done a lot of research on this and found cases where it would happen to some people with their mouse (what a PITA that would be.)

Erk! Where does one find that? Win XP SP4

I have been through all the USB hub settings for the computer and set them all to 'no powerdown', but didn't see any mention of Selective Suspend'.
I have also just upgraded Mach from V3.042.040 to the latest version.
I haven't installed an extra earth strap yet as everything IS fully earthed fairly well ... and it would mean drilling a largish hole in the solid steel cabinet for the earth wire and the USB cable, and ... I'm am lazy ... but it may still happen.

Cheers
Roger

I would like to say a big thank you to all who have contributed to the solution of this frustrating issue.
I was on the point of ditching my SS as it was more trouble than it was worth, but it is now working a box of fluffy ones.
The SS would error simple by turning on the Dust collector or even my vacuum cleaner. I was too scared to go near the dam thing while it was cutting in case it failed and even then it still stopped for no apparent reason.
I did the removal of the Capacitor and resistor from the board and there was an instant improvement. I could still trip the SS with my Dust collector but it was now hard to do and I had to flick it on and off in a way it would never be used to do it. In real world testing the SS would still fail intermittently but nothing like it did previously and I was able to work in my workshop again without fear.
Just before I found the mod I had ordered some ferrite cores for my USB cables and they turned up in the mail 2 weeks after I did the mod. I had nothing to loose so I clamp a ferrite coe on every end of the USB cables and 2 on the one going into the SS. If it's worth doing, it's worth over doing.
That was a month ago and I haven't had a single failure since.    
I passed my findings onto a few other people who were having problems and it has fixed their issues as well.
I can recommend the mod to anyone have issues and also adding Ferrite cores for good measure

 

Brett

Is it still a good idea to remove the mentioned components?  Or should I just see if everything is going to work first?  Is there a reason to not remove the components?

I bought my SS last year, but am just now beginning to put it to use.

I would not remove the resistor/cap unless needed. There are a few PCs where it helps but others it causes more problems. There are also better ways to isolate the USB signal now (if needed).