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June 2009

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Subject:
From:
Steve Gregory <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Steve Gregory <[log in to unmask]>
Date:
Tue, 23 Jun 2009 09:43:03 -0500
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So far, we've isolated down to one datecode, and we have quite a few of
the bad date code. Problem is, we've had these in stock for a while, and
I don't know if anybody is going to pony up and take responsibilty for
them and replace them for us.
 
Here's what the other datecodes look like:
 
http://stevezeva.homestead.com/files/Good_DensiPac.jpg
 
Just a little better looking huh?
 
Steve

________________________________

From: [log in to unmask] [mailto:[log in to unmask]]

Sent: Tuesday, June 23, 2009 7:22 AM
To: TechNet E-Mail Forum; Steve Gregory
Cc: [log in to unmask]
Subject: Re: [TN] "Blumpie" looking connector leads...



Hi Steve - ah, the beauty of being a materials engineer is that the
industry doesn't seem to learn from past material mistakes so I really
don't need to learn anything new! I recommend you check with your
connector vendor to confirm that the connector surface plating is bright
acid tin. The photos appear to show a bright acid tin surface finish
that has blistered during the solder reflow process due to excessive
co-deposited organic material. Bright acid tin finishes (plated
correctly) look very nice but have terrible solderability
characteristics and are a known tin whisker generation source.  It
appears that you may have had a surface plating change from what you
normally had been procuring. Good luck. 

Dave Hillman 
Rockwell Collins 
[log in to unmask] 




Steve Gregory <[log in to unmask]> 
Sent by: TechNet <[log in to unmask]> 

06/23/2009 06:49 AM 
Please respond to
TechNet E-Mail Forum <[log in to unmask]>; Please respond to
Steve Gregory <[log in to unmask]>


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Subject
[TN] "Blumpie" looking connector leads...

	




 Morning all!

Trying to stay cool here! Broke 100 degrees yesterday and Sunday, and
it's probably going to break 100 degrees today. Summer has come with a
vengeance! 

Ran across something yesterday that I've never seen before. We build a
board that uses this AMP Densipac SMT connector:

http://tinyurl.com/nqbpcp


We've built a lot of these boards before without any issues at all. This
latest run we have something going on with these particular connectors.
Here's a photo of them on the PCB:

http://stevezeva.homestead.com/files/AMP_Connectors.jpg

You can probably see that the leads have this "Blumpie" look to
them...both bumpy and lumpy. This is fresh out of the reflow oven.
Here's a closer look:

http://stevezeva.homestead.com/files/Connector_Blumpies.jpg

If you notice the two pins either side of the white line look fine. They
are the anchor pins that are for mechanical strength for the
connector...they are not I/O pins. The rest of the board looks
absolutely fine too. Not a bit of problem. It's just the I/O pins. We
have noticed that connectors with certain date codes don't have this
problem. Also, before reflow the connectors look okay. Luckily we've
only built a few boards, and we're stopping until we can get to the
bottom of this...

Have any of you ever seen "blumpie" connectors like these before?

Steve

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