Hi Inge, Unfortunately, for solder joints the MTBF-concept makes little sense because they fail as the result of wear-out. If you look at the wear-out of solder joints of a large population, you see almost a 2-order of magnitude between first failure and last failures, since the Weibull shape factor is about 3. For some laptops rhyming as the one previously mentioned, out-of-the-box failures have been reported with most failure having occurred in ghe 12 to 24 months range--depending on usage, of course. The problem is a design issue with large component, large delta-CTE, large on/off T-difference, little lead compliancy—a textbook case of how not to do it. Werner ************************************** See what's free at http://www.aol.com. --------------------------------------------------- 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 -----------------------------------------------------