I think maybe you removed the smoking gun, as Chuck is indicating, by having too much current during test. If you have more of these types of defects you should be able to detect their presence at much lower currents so that hopefully you can see the nasty little bugger which was responsible. I presume the boards were continuity tested post manufacture, and the shorts developed later. What was done to the boards in the interim. Biased humidity perhaps? If that's the case, could be CAF. Wayne Thayer >>> [log in to unmask] 5/8/2007 12:53:38 pm >>> Iian, Stop fixing small shorts with your hi pot tester. Wow, Big flash and the short is gone leaving you on pic 1 a delaminated area and on pic 2 the burnt remains. Bet if you look real close you will find a sliver of metal or a copper fiber. Chuck Brummer 3M Manufacturing Engineer 8357 Canoga Ave. Canoga Park, CA 91304-2605 (818) 734-4930 "Braddock, Iain" <[log in to unmask]> Sent by: TechNet <[log in to unmask]> 05/08/2007 09:23 AM Please respond to TechNet E-Mail Forum <[log in to unmask]>; Please respond to "Braddock, Iain" <[log in to unmask]> To [log in to unmask] cc Subject [TN] Strange one? Hi all, Stevie G has been kind enough to post a couple of pics of a flexi anomaly I've come across. Been having problems with some flexi-rigid boards failing at Ins/Cons test due to insulation breakdown - tested at 200v. Had the lab do some exploratory work and the guys have come up with these pics. along with the fact that the Polyimide was conductive around the areas highlighted on the pics. but only localised. The Lab view seems to be that something was left on the board during fabrication and caused the problem; they have their suspicions but would like to know if anyone else has encountered a similar problem. http://stevezeva.homestead.com/files/Flex_Problem_1.JPG <http://stevezeva.homestead.com/files/Flex_Problem_1.JPG> http://stevezeva.homestead.com/files/Flex_Problem_2.JPG <http://stevezeva.homestead.com/files/Flex_Problem_2.JPG> Regards, Iain. ******************************************************************** This email and any attachments are confidential to the intended recipient and may also be privileged. If you are not the intended recipient please delete it from your system and notify the sender. You should not copy it or use it for any purpose nor disclose or distribute its contents to any other person. MBDA UK Limited, a company registered in England and Wales, registration number 3144919 whose registered office is at Six Hills Way, Stevenage, Hertfordshire, SG1 2DA, England. ******************************************************************** --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------