Keith, Did all of these assemblies happen to have one of the components replaced/changed that is connected to the open trace? I am assuming this is a through-hole PWB. A broken bit fault would be more random as would an overall PWB processing defect. The failures wouldn't manifest in the same location in every instance. I'd suspect some latent thermal damage to the PWB during the assembly process. The thermal stress from reworking a through-hole component, if not well controlled, can lead to this type of failure. I'd also look at the artwork/master pattern for the PWB and see where the trace goes. This may give you a clue where the fault is (again, look at through-hole rework locations). Another possibility is electrical overstress. If the trace in question carried too high of current, it could burn open. This would be visible on a decent xray system. Causes could be poor design or an external fault to the card. The only time I have observed a pattern failure like this that was an actual PWB defect, it was due to bad artwork. And we saw those during production - they did not make it to the field. Good luck, -- Gregg At 10:15 AM 11/12/2003, Keith Calhoun wrote: >hoping that Technet could once again help me with a vexing problem. We >have had a number of boards which have been returned from the field that >fail during our testing. We have identified the problem as an open >trace on an inner layer between one or more IC's and the card edge >connector. All of these opens appear to be found on the same inner >layer, and all the boards which show this failure have the same date >code on the bare boards. We have tried to have these boards x-rayed to >determine if we could find any problems, but we were unable to locate >any problems. We can identify the area on the boards as being somewhere >in about a 2-3 sq. in. area. I am interested in finding out about any >other methods, sources, etc which we can use prior to destructive >investigation of this problem. Again your help is greatly appreciated. > --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e 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 847-509-9700 ext.5315 -----------------------------------------------------