Phil It is not only the shock but also the time of the acceleration that's applied and, very important in my opinion, how the PCB is fixed and in which direction of the board the shock is applied since it is not just the force resulting from acceleration and the mass of the components that destroys solder joints and components but the shock wave that travels trough the PCB will cause a deformation of the board and this is even worse. I couldn't say what the BGA's will say to the shock. But I have the feeling that the discrete SMT's will have no problems with the force coming from their mass. Best regards Guenter Guenter Grossmann Swiss Federal Institute for Materials Testing and Research EMPA Centre for Reliability 8600 Duebendorf Switzerland Phone: xx41 1 823 4279 Fax : xx41 1823 4054 mail: [log in to unmask] --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d 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 delivery of Technet send the following message: SET Technet NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------