Hi Gil! That's the way I like my failures! Very dramatic! We can presume that the observed phenomenon is the result of too much current going through too little conductor. How did that much current get there? To answer that question, you must first draw a "fishbone" diagram which shows how many different ways you could get current in the offending conductor high enough to cause it to melt. For example, a partial list: -failed component on surface of the board -overcurrent on board I/O -reduction in cross sectional area for the conductor which melted (unlikely, but possible) -mechanical damage to board causing internal short -CAF or other migration path -overvoltage resulting in arcing and build-up of carbon deposits You get the idea. Then you form a consensus on the most likely/quickest or cheapest to diagnose and weed out those fast. After those are weeded out, you re-investigate all of the data and come up with experiments/research to indicate probabilities of the items on the list you couldn't eliminate yet. If your real question is whether CAF could do that, yes it can. It should definitely be on the list. Unfortunately, it sounds like the "smoking gun" probably got smoked a little too much. But not to worry since extended bias/humidity testing with the remaining pieces of circuit board may be able to generate additional conductive paths for you to analyze. Wayne Thayer -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Zilber Gil Sent: Tuesday, September 04, 2007 1:26 PM To: [log in to unmask] Subject: [TN] Help needed on motherboard failure analysis Hi, Recently one of our motherboard failed. It reaches very high temperature that melts the copper and explodes shooting (from the side of the board) the melt copper to over 20 cm. the shooting hole cause delamination of the board in the area. A lot of black smoke and was also seen. The max voltage of the board is about 50V. The board worked fine for more then a year. What could be the failure mechanism? Could it be due to conductive filament formation (although the PCB should be free of that)? Thanks Gil Zilber Elta Systems The information contained in this communication is proprietary to Israel Aerospace Industries Ltd. and/or third parties, may contain classified or privileged information, and is intended only for the use of the intended addressee thereof. If you are not the intended addressee, please be aware that any use, disclosure, distribution and/or copying of this communication is strictly prohibited. If you receive this communication in error, please notify the sender immediately and delete it from your computer. Thank you. This message is processed by the PrivaWall Email Security Server. --------------------------------------------------- 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 -----------------------------------------------------