Does the EOL test perform hi-pot test? High line voltage test? Dropped neutral test? Also, considered peak AC volts, in this case about 120V X 1.41? Also appears "white streak" could be culprit, or is it an artifact of board section process? Seems to follow glass weave. Could this be CAF related? Many forms of FR-4 are rated at around 500V/mil, but I normally figure on 100V/mil to be safe. Hope you resolve this issue, Roger (aka part-time lurker) -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Jack Olson Sent: Wednesday, November 21, 2007 11:58 AM To: [log in to unmask] Subject: [TN] Core Quality Issue? Sorry to re-start a previous discussion, but I'm still dealing with a board failure and I'm trying to learn fast. I received a higher-resolution picture of a board problem we are having http://www.frontdoor.biz/PCBportal/corequestion.jpg<http://www.frontdoor .biz/PCBportal/corequestion.jpg> and if I look at it closely, I can see the dividing line between all ten layers of dielectric. By looking at which way the copper is located from each dividing line, I can tell which are cores and which are prepreg (because the prepreg layers will flow "around" the copper features) For example, the thin pinkish layer is a core. Am I on the right track so far? So, our problem is a 120V end-of-line test frying two out of every hundred boards right through the pinkish core material with the white streak through it (3.2 mils, which should handle a few kilovolts at least, right?) So here's the question: Should I be questioning the material quality rather than the bare-board manufacturing process itself? I realize you guys have already been generous with helping me on this, so I hope I'm not pushing your patience... onward thru the fog, Jack (aka "the new guy") --------------------------------------------------- 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 -----------------------------------------------------