Gil, Is this a howitzer of some kind? What motherboard? Computer or servo system or medical apparatus or what? We may get a clue if you could describe the board a little. How many layers? Power supply capability? Fuses? Connector size? Capacitor size? Is this an office box, outdoor working, in a vehicle or what? Sounds to me as not being an office machine. 50 Volts is a lot. You may get some 100 amperes of current during milliseconds, which means maybe a 5,000 Watt spike, enough to cause severe damage. My first idea is an incoming transient. Have you checked the status of the components on the board. That should be first step. Finally , I don't think the cause is the board. Start checking the components. Blown power tyristors, FETs, transistors? Look for cooling problems, number one today. Check inductors, DCDCs, tranformers, if there are any on the board. Look for overheated components that can have melted solder in PTHs. Wished I had that board on my desk, very delicate case! Inge -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Zilber Gil Sent: den 4 september 2007 19:26 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 -----------------------------------------------------