Hi Lyon, Most commonly, people use solder-wick to clean the pads of a BGA if it is to be re-balled. This is a delicate operation, and great care must be used when doing this. The solder-wick must not be dragged across the pads, and the soldering iron and wick must be removed at the same time. I have seen pads pulled when the iron is removed first, then the wick pulled after the solder has solidified...the pad comes off with the wick. Steve -----Original Message----- From: Lyon Yuan [mailto:[log in to unmask]] Sent: Wednesday, September 4, 2013 8:21 AM To: Steve Gregory; [log in to unmask] Subject: RE: [TN] EXTERNAL: [TN] BGA pad drop Hi Steve, Sorry, can you give more details? Thanks Lyon Yuan -----Original Message----- From: Steve Gregory [mailto:[log in to unmask]] Sent: Wednesday, September 04, 2013 10:16 PM To: [log in to unmask]; Lyon Yuan Subject: RE: [TN] EXTERNAL: [TN] BGA pad drop Well, well, well....there's your answer. I think someone did not have a delicate touch when they cleaned the pads... Steve -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Lyon Yuan Sent: Wednesday, September 4, 2013 8:14 AM To: [log in to unmask] Subject: Re: [TN] EXTERNAL: [TN] BGA pad drop Hi Steve Yes, it was re-balled Lyon Yuan From: stephen gregory [mailto:[log in to unmask]] Sent: Wednesday, September 04, 2013 10:11 PM To: Lyon Yuan; TechNet E-Mail Forum Subject: Re: [TN] EXTERNAL: [TN] BGA pad drop Hi Lyon! Have your picture posted, it's here: http://stevezeva.homestead.com/Pad_missing.JPG Do you know if this BGA was re-balled? Steve From: Lyon Yuan <[log in to unmask]> To: 'stephen gregory' <[log in to unmask]>; 'Steve Gregory' <[log in to unmask]> Sent: Wednesday, September 4, 2013 8:00 AM Subject: RE: [TN] EXTERNAL: [TN] BGA pad drop Steve, Help to upload picture to web. Thanks Lyon Yuan -----Original Message----- From: Wenger, George M. [Contractor] [mailto:[log in to unmask]] Sent: Wednesday, September 04, 2013 9:54 PM To: Lyon Yuan Cc: stephen gregory; Steve Gregory Subject: RE: [TN] EXTERNAL: [TN] BGA pad drop Lyon, Attached is a link to his site. The last emails I had for Steve are on the copy to line of this email <http://stevezeva.homestead.com/> http://stevezeva.homestead.com/ Regards, George George M. Wenger Failure Signature & Characterization Lab LLC 609 Cokesbury Road, High Bridge, NJ 08829 (908) 638-8771 Home (732) 309-8964 Mobile E-mail: <mailto:[log in to unmask]> [log in to unmask] <mailto:[log in to unmask]> [log in to unmask] -----Original Message----- From: Lyon Yuan [mailto:[log in to unmask]] Sent: Wednesday, September 04, 2013 9:45 AM To: Wenger, George M. [Contractor] Subject: RE: [TN] EXTERNAL: [TN] BGA pad drop George Thanks, steve's email? Lyon Yuan -----Original Message----- From: Wenger, George M. [Contractor] [mailto:[log in to unmask]] Sent: Wednesday, September 04, 2013 9:35 PM To: TechNet E-Mail Forum; Lyon Yuan Subject: RE: [TN] EXTERNAL: [TN] BGA pad drop Hi Lyon, You might want to send the picture to Steve to post on his site so we all can see it. Regards, George George M. Wenger Failure Signature & Characterization Lab LLC 609 Cokesbury Road, High Bridge, NJ 08829 (908) 638-8771 Home (732) 309-8964 Mobile E-mail: <mailto:[log in to unmask]> [log in to unmask] <mailto:[log in to unmask]> [log in to unmask] -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Lyon Yuan Sent: Wednesday, September 04, 2013 9:32 AM To: [log in to unmask] Subject: Re: [TN] EXTERNAL: [TN] BGA pad drop Hi Ben, I send a clear picture for your reference Lyon Yuan -----Original Message----- From: [log in to unmask] [mailto:[log in to unmask]] On Behalf Of Gumpert, Ben Sent: Wednesday, September 04, 2013 8:04 PM To: [log in to unmask] Subject: Re: [TN] EXTERNAL: [TN] BGA pad drop Lyon, I haven’t seen that. Typically the pads on the BGA are solder mask defined, which makes them much more secure than the usual non-solder mask defined pads on the PWB. Ben From: [log in to unmask] [mailto:[log in to unmask]] Sent: Wednesday, September 04, 2013 7:04 AM To: Gumpert, Ben Cc: TechNet Subject: Re:Re: [TN] EXTERNAL: [TN] BGA pad drop hi ben, it is pad missing from bga 在2013/09/04, "Gumpert, Ben" < <mailto:[log in to unmask]:[log in to unmask]> [log in to unmask]<mailto:[log in to unmask]>> 写道: Lyon, By 'pad drop' do you mean lifted pads? (Pads stayed with the BGA?) Usually this means that there wasn't enough heat - that the solder was not melted in all locations. Ben -----Original Message----- From: TechNet <mailto:[mailto:[log in to unmask]]> [mailto:[log in to unmask]] On Behalf Of Lyon Yuan Sent: Wednesday, September 04, 2013 6:40 AM To: <mailto:[log in to unmask]:[log in to unmask]> [log in to unmask]<mailto:[log in to unmask]> Subject: EXTERNAL: [TN] BGA pad drop guys,we found a few BGA pad drop after removed from pcba boards.what is reason to cause the issue ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. For more information please contact helpdesk at x2960 or <mailto:[log in to unmask]:[log in to unmask]> [log in to unmask]<mailto:[log in to unmask]> ______________________________________________________________________ ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. For more information please contact helpdesk at x2960 or <mailto:[log in to unmask]:[log in to unmask]> [log in to unmask]<mailto:[log in to unmask]> ______________________________________________________________________ ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. For more information please contact helpdesk at x2960 or <mailto:[log in to unmask]> [log in to unmask] ______________________________________________________________________ ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. 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