On 2007-09-13 12:58, John Burke wrote: > I am assuming that the close up shots are Z axis sections? Yes. Sorry, I should have described them better. > Which if they are, and those are indeed inner layers, the > board is showing signs of unusual localized deformation since > the "two halves" of the break are not aligned, and if this is > indeed an inner layer section, they should be, broken or not. Yes, I believe there are two phases leading to the final condition: an inital defect (still very conductive), followed by later separation (higher R or open), possibly under stress. > Have you taken a look at the test fixture for the final board > assembly? You can sometimes get very bad local board > deformation due to uneven pusher pin distribution. No but that is an interesting suggestion, thanks. Mike --------------------------------------------------- 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 -----------------------------------------------------