Hi Andre! I would suggest you get a Scanning Electron Microscopy element scan conducted on the white residue. The white residue you describe could be tin or lead oxides, lead crystals due to a component plating problem, calcium crystals due to poor washing, etc. The SEM analysis will help eliminate the inorganic (e.g. metallic) possibilities leaving the possible flux related (organic) source causes. Good luck and Happy Holidays. Dave Hillman Rockwell Collins [log in to unmask] Andre Leclair <[log in to unmask]>@ipc.org> on 12/19/2001 07:57:26 AM Please respond to "TechNet E-Mail Forum." <[log in to unmask]> Sent by: TechNet <[log in to unmask]> To: [log in to unmask] cc: Subject: [TN] white powder on leads Hi All Here is another residue issue We have an assembly which has a white residue remaining after wash. The board is completely SMT (WS609) using a DI-Wash process, the board is spotless except for one location. The location is a QFP (from CRONTEL), the white powder is on the leads of the IC only. There is not a spot on the PCB. The Powder dry brushes extremly easily. On a few of the leads ( usually about half way up the lead, nver near the joint)after brushing there is evidence of flux residue( yellow sort of like Crystal Flux residue) in spots. We have put a few boards through the Omega with readings lower then 2.3microgram/sq.inch. Could this be something the part manufacture has left/put on the leads? I have noticed that the plating is thin on the leads (exposed copper on the faces) the leads also look like sheared stock ( exposed copper on the sides) Thanks Andre --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d 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 delivery of Technet send the following message: SET Technet NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 --------------------------------------------------------------------------------- --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d 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 delivery of Technet send the following message: SET Technet NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------