Yeah, that is what happens if an assembly has been dropped or bent :-) Vladimir -----Original Message----- From: TechNet To: [log in to unmask] Sent: Fri Nov 17 11:39:07 2006 Subject: Re: [TN] One solder Ball Not Connected on a No Connect Pad After Rework Vladimir, You are right, it is just that I had this problem too and in the end the conductors had cracks and the pads were really lifted-(not ground pads solder mask defined)..I could see the cracks only by X-ray... Gaby ----- Original Message ----- From: "Vladimir Igoshev" <[log in to unmask]> To: <[log in to unmask]> Sent: Friday, November 17, 2006 7:06 PM Subject: Re: [TN] One solder Ball Not Connected on a No Connect Pad After Rework > Hi Gaby, > > It doesn't have to be cracked, particularly if the pad in question is > non- SMD. > > Regards, > > Vladimir > > -----Original Message----- > From: TechNet [mailto:[log in to unmask]] On Behalf Of Gabriela Bogdan > Sent: Friday, November 17, 2006 10:56 AM > To: [log in to unmask] > Subject: Re: [TN] One solder Ball Not Connected on a No Connect Pad > After Rework > > If the pad comes off it is because there is a crack between the pad and > the > base material, and no conductor is there to prevent it from coming off. > I > would suspect that if you do a cross section of active pads in the same > area > you have a fair chance to see such cracks unde the pads, and even lifted > pads. > You intend to replace the BGA on this area. Are you sure that the new > connections will be as good as new? > Gaby > ----- Original Message ----- > From: "bob wettermann" <[log in to unmask]> > To: <[log in to unmask]> > Sent: Friday, November 17, 2006 6:10 PM > Subject: [TN] One solder Ball Not Connected on a No Connect Pad After > Rework > > >> This question to the group is about expected solder joint strength on > a >> BGA. >> >> The BGA in question is a 8 x 8mm plastic package BGA using a LF > SAC305 >> soldering process. It has 64 x 0.018" balls holding it to the PCB. >> >> When removing this device for rework 3-4% of the time one of the > corner >> NO CONNECT pads comes off. >> >> The question is if we do nothing upon replacement of a new device > to >> the damaged pad will it really make a difference ??? We are arguing > that >> the holding strength of the reworked device would be approximately > the >> same because the change in overall surface area is marginally > impacted. >> >> >> Thanks >> >> Bob Wettermann >> >> >> Bob Wettermann >> >> --------------------------------------------------- >> 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 >> ----------------------------------------------------- >> PH 847-767-5745 >> > > --------------------------------------------------- > 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 > ----------------------------------------------------- > --------------------------------------------------- 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 -----------------------------------------------------