Hi Alex and the group, Often, one is very lucky to be able to fix such a problem while at the lab. Time there is best spent collecting data on the failure. Things like the actual failure voltage, cable positioning effects, and the such are important data that will make your device easier to troubleshoot in the lab.
There are lots of troubleshooting techniques described on my website (www.dsmith.org). For instance, trigger a scope from the EFT generator and then use a magnetic loop (insulated paperclip will do) to trace the EFT current flow through your product. Once the exact path is known, often the solution is obvious. Because the EFT signal is (sort of) continuous and easy to trigger on, I have found EFT problems very easy to fix. Forget using any commercial scope probes though, they are useless in an EFT environment, too senstive to stray pickup. For products with metal enclosures, the balanced coaxial probe described on my website can measure signal voltages in the presense of ESD or EFT in equipment. I am working on a new balanced probe design that will work even better for this use as well as on signals past 1 GHz, but my first prototypes will not be ready for a few months, too late for your problem. Doug Alex McNeil wrote: > > Hi Guys, > > I am at an EMC test centre today and tomorrow. Unfortunately, my product > failed EFT testing on the AC power port at 1KV. This is for various > combinations of Line, Neutral and Earth (L, N, E, LN, LE, NE and LNE) > > My product is Class II, no Earth. It is supplied by an external power > supply. This supplies SELV to my product. The power supply manufacturer has > stated that his power supply meets EN61000-4-4 for 2KV and has emailed me > this report to verify this. > > Has anyone got a quick solution to my problem so that I can implement here > at the EMC test house? > > Kind Regards > Alex McNeil > Principal Engineer > Tel: +44 (0)131 479 8375 > Fax: +44 (0)131 479 8321 > email: [email protected] > > ------------------------------------------- > This message is from the IEEE EMC Society Product Safety > Technical Committee emc-pstc discussion list. > > Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ > > To cancel your subscription, send mail to: > [email protected] > with the single line: > unsubscribe emc-pstc > > For help, send mail to the list administrators: > Michael Garretson: [email protected] > Dave Heald [email protected] > > For policy questions, send mail to: > Richard Nute: [email protected] > Jim Bacher: [email protected] > > All emc-pstc postings are archived and searchable on the web at: > No longer online until our new server is brought online and the old > messages are imported into the new server. -- ------------------------------------------------------- ___ _ Doug Smith \ / ) P.O. Box 1457 ========= Los Gatos, CA 95031-1457 _ / \ / \ _ TEL/FAX: 408-356-4186/358-3799 / /\ \ ] / /\ \ Mobile: 408-858-4528 | q-----( ) | o | Email: [email protected] \ _ / ] \ _ / Website: http://www.dsmith.org ------------------------------------------------------- ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson: [email protected] Dave Heald [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
