Looks like outgassing or plating lifting. Simple just take a part under a microscope and with a soldering iron hold the tip to the surface of the lead. I normaly tin the tip then wipe it dry before touching the plated surface. Sometimes I test chip components in hot oil to see the surface outgas! It makes great video to show suppliers!!
 

Bob Willis
2 Fourth Avenue
Chelmsford, Essex CM1 4HA
England
Tel 01245 351502
Fax 01245 496123
www.ASKbobwillis.com

New International Workshops & Agenda www.ASKbobwillis.com/faworkshops.pdf
 

-original message-
Subject: [TN] "Blumpie" looking connector leads...
From: Steve Gregory <[log in to unmask]>
Date: 23/06/2009 13:57

 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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