Hi Gary, Hey, don't complain! Poor designs keep us EMC engineers fully employed!
I've run into this myself on occasion - that is, until I started educating our designers. :-) Try running a -short- ground connection from the PC board ground << at the video connector >> to the nearest chassis ground. That ought to divert at least some of the common-mode current back to the source. You may be able to use some commercially available fingerstock or springy "dots". I presume you've already tried the usual ferrite choke on the cable? This treatment will likely need to be done at every cable egress. Most video cable are already shielded, so the trick is to get that shield connected direct to chassis with a short (as possible) connection. This, of course, presumes the chassis IS using a shielded enclosure already. Use of a current probe on the video cable is all you need to troubleshoot this and you'll be able to see the results in real-time. Ken Wyatt Technical Services, LLC 56 Aspen Dr. Woodland Park, CO 80863 Email: k...@emc-seminars.com Web: www.emc-seminars.com http://www.linkedin.com/in/kennethwyatt (719) 310-5418 On Dec 14, 2009, at 9:55 AM, McInturff, Gary wrote: We have a poor design handed to us and trying to figure out the easiest way of adding some shielding with having to modify enclosures etc. I have a cable shielding need between a video display and a base unit – but the connectors are located inside the respective housings so I can’t use bulkhead style connectors. I’ve got the mechanical guys looking at a flexible – “conduit” between the units but I’m also interested in shielded flat cable and PC mount connections. Anybody have a source they’ve used in the past? - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <emc-p...@ieee.org> All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <emcp...@socal.rr.com> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher <j.bac...@ieee.org> David Heald <dhe...@gmail.com> - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <emc-p...@ieee.org> All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <emcp...@socal.rr.com> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher <j.bac...@ieee.org> David Heald <dhe...@gmail.com> - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <emc-p...@ieee.org> All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <emcp...@socal.rr.com> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher <j.bac...@ieee.org> David Heald <dhe...@gmail.com>
