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November 1997

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Subject:
From:
Doug Pauls <[log in to unmask]>
Reply To:
TechNet Mail Forum.
Date:
Tue, 4 Nov 1997 09:16:13 -0500
Content-Type:
text/plain
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text/plain (38 lines)
In a message dated 97-11-04 05:05:57 EST, you write:

> Can any one help me with a solution to this problem,

I'll give it a shot.

>  we have recently experenced board failures because of a contamination
>  across various sm  capacitors which first looks like a splat of black
paint
>  which run diagonally across the cap, under a microscope it looked like
>  fern leaves.

The black material could be a number of things:  dense dendritic growth,
carbonizing from an arc, leaking electrolytic solution from a cap, stray
encapsulant material, etc.  If I could see it, I would have a better idea.
 Any chance of making a digitized photo and sending me one?  The "fern leaf"
structure indicates it is probably dendritic growth.

>  Our boards are wave soldered and w edo not clean after solder flow.

What are you wave soldering with and are you mixing any flux technologies?

Doug Pauls
CSL
[log in to unmask]

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