On Monday 30 January 2017 09:48:10 Lennart Sorensen wrote: > On Sun, Jan 29, 2017 at 01:48:50PM -0500, Gene Heskett wrote: > > Alan, ALL of the motor drivers are switchmode, with the current > > regulation running at or above 20 KHz. And these noise spikes are > > ringing at nominally 100 MHz. I have managed to get the xy motor > > noise under control by takeing out the switchmode psu's, and putting > > in tordoid transformers, bridge rectifiers, and the biggest > > electrolytic I had in the drawers that had sufficient withstand > > voltage. Its a star ground system, and the output cables to the > > motors are shielded, and the shield grounded as it goes by this > > single bolt ground on its way out of the box. The shielding extends > > both ways from that point but is not connected either at the motor, > > or at the driver, just at the bolt. This is std in such noisy > > machinery. > > Well the USB would probably be at either 12MHz (USB 1.x) or 480MHz > (for USB 2), but most likely USB1 for your keyboard. That certainly > is a potential place to hit with noise if you are getting spikes into > the 100MHz range. And USB cables don't appear to be that well > shielded in general (they seem to aim for cheap).
Another understatement. You folks are getting good at that. :) Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene>
