I would have to say you are correct, the testing for opens on BGAs is difficult, even with the HP 5DX machine we have here. I can't recall having seen a single open joint on a properly reflowed collapsible BGA, but we have seen them on non-collapsible. How would you attempt to verify that the package is parallel to the board surface? I know some of the OMPAC plastic packages that we use will occasionally be lower in the center than the edges, although not by very much. I look forward to other comments from Xray users about this subject. Paul Quintin Data General ################################################################ 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 ################################################################