Hi Tom: More than likely is what you are suggesting. To eliminate that possibility, you could send those parts by themselves through the reflow oven and they might just outgas all the organics or moisture that is trapped in the terminations that are causing this problem, then install them on the board and see if that is a patch cure. It seems to me that eventually you need to work with the part manufacturer to find the root cause. Regards, Ramon -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Gervascio, Thomas Sent: Wednesday, November 16, 2005 8:49 AM To: [log in to unmask] Subject: [TN] Snap ,crack and pop We have been seeing solder fines all over some PCMCIA boards we have build. We checked the degree of cure on the PCB, paste volume and paste oxidation and slump and checked the oven profile (tried both a ramp-soak and ramp to spike profile with 1 C/sec ramp rates). We then found that it only happened when certain resistors were used. All I know right now is that it is a RoHS (tin plated over nickel) on ceramic part- 0603. We put some boards on a hot plate and heard a sizzle and popping of the paste on a board that had these parts (didn't see the same on a printed bare board). What could be outgassing from the part terminations that would interact with the paste that would cause this explosive phenomena? Could the parts be tin plated and then fused? could it be some sort of organic material (brightener) that is remaining and outgassing? --------------------------------------------------- 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 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- 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 847-615-7100 ext.2815 -----------------------------------------------------