Hi Carl, it sound like you got a problem with your ENIG board. I'm not going to spell the "famous" BP word as saw a case with exact same symptoms and it nothing to do with BP.
The best you can do is to have the assembly analyzed. You can contact me off line if you want us to do it.
Vladimir
SENTEC Testing Laboratory Inc.
11 Canadian Road, Unit 7.
Scarborough, ON M1R 5G1
Tel: (416) 899-1882
Fax: (905) 882-8812
www.sentec.ca
-----Original Message-----
From: Carl VanWormer <[log in to unmask]>
Sender: TechNet <[log in to unmask]>
Date: Mon, 19 Sep 2011 12:48:23
To: <[log in to unmask]>
Reply-To: TechNet E-Mail Forum <[log in to unmask]>,
Carl VanWormer <[log in to unmask]>
Subject: [TN] large parts falling off finished surface mount board assemblies
A surface mount PC board assembly (made by a local assembly house and
passed by our outgoing test) was returned from the end user, along with
an electrolytic capacitor that they had "knocked off" the board. After
looking at the assembly and component under a microscope, I noticed that
the "gold plated" PC board (Lead free) had a fine granular solder
appearance (much smaller grain than solder paste balls) on the pads
newly exposed, with the whole "melted solder" blobs (in the shape of the
pads) attached to the capacitor leads (with a similar granular
appearance). After minor scraping of various parts, I had come to no
brilliant conclusions, so I pressed my finger nail against an inductor
that was of similar size to the capacitor. It popped off the board with
the same symptoms as the capacitor. After recovering from my surprise,
I realized that I have no clue about the causes or cures for my
component adhesion problem. Can any of the more experienced members of
this fine group direct me to some key words that might lead me to a
quick education (and solution)?
Thanks,
Carl
Carl Van Wormer, P.E., AE7GD
Senior Hardware Engineer
Cipher Systems
1800 NW 169th Place, Suite B-100
Beaverton, OR 97006
Cipher Systems (503) 617-7447 x 5163
Direct Line (503) 425-5163
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