Quote Originally Posted by eurikain View Post
Jazz, I'm not sure to understand what you are saying... will the ESS fix the issue IF it is a ground loop going to the PC ?

I have tried getting rid of the ribbon cable. Same problem, though I had disconnected the X axis motors because I didn't want to twist the gantry. But then it was a little more difficult to hear the noise but it was still there. I will do some more tests on Thursday, I'll connect everything back together to get the maximum noise, then disconnect the DB25 cable and see if that stops it. I'll let you guys know ASAP.
In theory yes it should but like been said depends if this really is the source of trouble.? That said I'd still change the BOB because it's clearly not very good because shouldn't happen even with parallel port.

Now like Clive ask's What Noise.?

I think you miss under stand what is meant by Noise. It's not audible so if your hearing any noise that's something else.?
If your using AM Digital drives then I suspect it's because you haven't tuned them. Or what your hearing is the current reduction in the drive working while motors are stood still. This will make an Hissing sound.

Electrical noise or EMF is a Silent Killer.!!

Very difficult to help from distance when it comes to noise. All you can do is be meticulous with wiring and gnding. Ensure separation between signal and power cables.
If still present then fit EMF Filters etc.

If still present then start back tracking.