Hi All - Well here we go again with another one of those "you can't get there from here" questions. We're looking at the conversion of a VME sized CCA from use in benign environments to use in severe service environments. The design is about 80% surface mount. We've conjured up the necessary stiffeners, etc., for the board and have most of the problems worked out EXCEPT for three PBGA's about 1.25" square. These 1.25" pitch devices have finned aluminum heat sinks, to add to their mass. The final laminate material hasn't been selected, but I would expect to go with IPC-4101/26 or better to obtain a fairly high Tg. Has anyone had any experience with MIL temp range thermal cycling and vibration of PBGA's in this size and structure? ... and if so, with what degree of success? Would appreciate any comments. Have a good day - Kelly ################################################################ TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c ################################################################ To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TechNet <your full name> To unsubscribe: SIGNOFF TechNet ################################################################ Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################