Help! Steppers losing steps and making a racket under slow feed..

[fasteddy]

Morning Jonathan..!

Tried all kernal speeds from 25KHz to 60Khz, makes no difference...

Seems my PC is a dual processor, 2 x 3GHz P4... Have it set for standard PC and have done all the optimizations recommended for Mach3.. Really is a bare bones machine and runs very fast, boots in 11 secs... Even running complex code the processors never get to more than 4% usage... Everything disabled that is of no use, using a pci graphics card (not onboard one which seems to be an issue on some machines)..
Re-checked all my cables and drivers/board (which are very cool due to a pair of fans mounted above them)..
Just swapped round a motor (had 2 spare 3Nm) and made no difference..

Am at a loss now.. No hair left to pull out and no idea what to try next...

Steve..

[Jonathan]

I'd leave it on the lowest kernel frequency as that is inherently the most stable.

Maybe the fans are causing interference in the step/dir inputs ... seems unlikely but you never know. Shielded cable might be the answer, but I reckon there must be more to it.

Try EMC? If that works you know the computer is ok.

Have you definitely wired the optocouplers the right way round on the driver?

(Would type more but I'm going out for the day, now ... hence why I'm up early! Hmm, 800th post.)