Roger, Any change of the stack order has the potential to change the conducted and radiated emission signature. A significant investment ($$$$) was made through the FCC and CE testing to get the design "qualified", which technically means that the design at that point is "locked" and cannot change. Changing a qualified design invalidates that qualification. Unless the customer specifically authorized a change in the "qualified" design, the new board house should either assemble the board as originally designed and qualified, or foot the bill to have the new stack design tested and requalified. And yes, the layer stack drawing should have been part of the original qualification submittal. Bob Cooke -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Roger Stoops Sent: Tuesday, July 13, 2004 8:05 AM To: [log in to unmask] Subject: [TN] Board Stack geometry This brings up a question I have had bumping around in my head for a while, for example: A pcb has been designed, assembled, tested, and now goes through FCC and CE emissions and susceptibility testing. The board stack was determined by the pcb vendor. The assembly passes first time. Purchasing or the EMS finds a less expensive yet reliable board house and buys production boards from this new house. The new house changes the board stack to their preferred lay-up. Would not this board need re-testing for FCC/CE emissions/susceptibility? For boards requiring this type of testing, would not a board stack specified on the print be required? TIA and much appreciated, Roger Stoops -----Original Message----- From: Jeffrey Bush [mailto:[log in to unmask]] Sent: Monday, July 12, 2004 8:40 AM Subject: Re: 7628 prepreg? Common type, stable, low resin content and likely predicable thickness is this is important. Otherwise PCB house should be left to determine the optimal stack for the board geometry and end use. Jeffrey Bush Director, Quality Assurance and Technical Support 76 Technology Drive - POB 1890 Brattleboro, Vermont 05302-1890 Tel. 802.257.4571.21 Fax. 802.257.0011 [log in to unmask] http://www.vtcircuits.com -----Original Message----- From: Brooks,Bill [mailto:[log in to unmask]] Sent: Friday, July 09, 2004 5:08 PM To: [log in to unmask] Subject: [TN] 7628 prepreg? Bill Brooks PCB Design Engineer , C.I.D., C.I.I. Tel: (760)597-1500 Ext 3772 Fax: (760)597-1510 http://pcbwizards.com Why would a designer specify 7628 prepreg in the construction of a board? What characteristics are unique to it? Bill Brooks, CID --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e 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 847-509-9700 ext.5315 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e 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 847-509-9700 ext.5315 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e 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 847-509-9700 ext.5315 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e 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 847-509-9700 ext.5315 -----------------------------------------------------