Hi Bob,

There pads are function pads so I want to find out root cause since I need
send some samples to vendor for FA. I don't want them to question us why
pads are missing

Lyon Yuan


-----Original Message-----
From: [log in to unmask] [mailto:[log in to unmask]] On Behalf Of Bob
Wettermann
Sent: Wednesday, September 04, 2013 9:15 PM
To: [log in to unmask]
Subject: Re: [TN] EXTERNAL: [TN] BGA pad drop

Lyon:

Are these pads "no connects" meaning they have no connection to outside
routing. If this is the case you may not need to worry about the missing
pads.

They can be easily repaired using either the epoxy or or dry film technique
as prescribed in IPC-7721.

Bob


On Wed, Sep 4, 2013 at 5:52 AM, Gumpert, Ben <[log in to unmask]> wrote:

> 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:[log in to unmask]] On Behalf Of Lyon Yuan
> Sent: Wednesday, September 04, 2013 6:40 AM
> To: [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
>
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-- 

   1. Bob Wettermann

847-767-5745


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