Steve: Had a recent experience with similar results where solder appears to wet the barrel but doesn't stay in the PTH. I also noted that the problem was randomin nature. Our process lab here took one of the affected boards and microsectioned a couple of holes. What they found were, excessive nodules, roughness and plating voids. This condition could cause outgassing of the laminate. It appears in your case the PTH's outgassed completely. I had some of what you had plus some joints with the usual outgassing bubble. Thinking initially that it was moisture, we baked the boards out. This did not help. We manged to narrow the problem down to a board lot and we got the board fab house to confess and replace the boards. The board house blamed the problem on a condition called "folding" where volitiles are trapped due to drilling problems. We did not find any evidence of this. I think you have a "bad" lot of boards. Bill Kasprzak Moog Inc. ################################################################ 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 ################################################################