Hi John! Hey, don't feel guilty. Contribute when you can and when you think its appropriate. The greatest quality of Technet is everyone's effort help out someone else who has an issue to solve in an noncommercial, proactive manner - sometimes that one nugget of information is the key to helping someone push a problem into the solved pile. Good Luck on your solderability case. Dave Hillman Rockwell Collins [log in to unmask] John Foster <john@BROADBANDINNOV To: [log in to unmask] ATIONS.COM> cc: Sent by: TechNet Subject: Re: [TN] Question about wetting <[log in to unmask]> 10/17/2003 05:10 PM Please respond to "TechNet E-Mail Forum."; Please respond to John Foster Everyone thank you so much for the replies to my question. I sometimes feel guilty because I don't have enough knoweledge to contribute too much to the thread. But I always know that I can come here for help with questions. Once again Thank You very much for replying John Foster -----Original Message----- From: TechNet [mailto:[log in to unmask]]On Behalf Of Dave Hillman Sent: Friday, October 17, 2003 1:40 PM To: [log in to unmask] Subject: Re: [TN] Question about wetting Hi John! Solderability restoration can come in three flavors: chemical, electrochemical, and mechanical (ok, Rudy may correct me in that electrochemical is a chemical process!). Mechanical restoration requires physical removal of the suspect oxide (either tin oxide or tin/nickel intermetallic oxide) using an abrasive media/process - usually not very practical or component friendly. ROSA is an electrochemical method which works well (and Bev, my system's back up next week!) but can sometimes has a "must be used within x hours of restoration" restriction. There are a number of chemical restoration treatments (such as Kester's SolderNu and others) which strip off the offending oxide - these are good products but are sometimes not component friendly. Lastly , pretinning/retinning of the components with very active fluxes (some folks consider this a chemical method, some a mechanical method). Good luck on your restoration efforts. Dave Hillman Rockwell Collins [log in to unmask] John Foster <john@BROADBANDINNOV To: [log in to unmask] ATIONS.COM> cc: Sent by: TechNet Subject: Re: [TN] Question about wetting <[log in to unmask]> 10/17/2003 01:49 PM Please respond to "TechNet E-Mail Forum."; Please respond to John Foster One big problem we have is that the parts are not hermetic. In fact we are looking at a alternate part because of this. I am going to look into the mechanism of oxidation. Thanks for all of the ideas so far. John -----Original Message----- From: TechNet [mailto:[log in to unmask]]On Behalf Of Bev Christian Sent: Friday, October 17, 2003 11:42 AM To: [log in to unmask] Subject: Re: [TN] Question about wetting John, Are they non-solderable because the tin has oxidized, the tin has been consumed as tin/nickel intermetallic that has then oxidized or the tin was so porous the nickel has oxidized? Also are the parts hermetic? If they are hermetic and you are sure they are just surface tin oxidized, throw them in some dilute EDTA, wash with DI water, IPA and then retape. If it anything else you would have to use acid to dissolve off whatever layers are there and then immediately re-tin. Then there is an electrochemical way to strip off the bad layers called ROSA. But this assumes they are either hermetic or can be fixtured to just immerse the leads. I wouldn't want that job! And Dave Hillman's ROSA unit is not up and running at this time. EMPF's?? regards, Bev Christian Research in Motion -----Original Message----- From: John Foster [mailto:[log in to unmask]] Sent: October 17, 2003 2:14 PM To: [log in to unmask] Subject: [TN] Question about wetting I have a large inventory of trim capacitors that have exceeded the manufacturers shelf life by 2 years. Solderability testing has revealed inadequate wetting. The parts are on tape and reel. The plating is a thin layer of tin over nickel. We believe we have a oxidation problem. Does anyone have any ideas AT ALL on how we can recover these parts. The part has gone obsolete I have 86,000 of these things that I really really need to use. Any help would be appreciated Thanks John Foster --------------------------------------------------- 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 ----------------------------------------------------- --------------------------------------------------- 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 -----------------------------------------------------