Hi Steve - just a comment (great pictures). The fuzzy substance is a 
crystalline structure that is most likely a corrosion reaction root cause 
and is probably not a "whisker" - at least in the sense of what the 
industry defines as a tin whisker. I know if seems like a silly point but 
I am just trying to head off a future conversation with someone who saw 
Pat's "whisker" pictures and got the wrong idea without finding out all 
the facts. Sure would love to have a SEM EDX analysis of the substance to 
get a chemical identification.

Dave



Steve Gregory <[log in to unmask]> 
Sent by: TechNet <[log in to unmask]>
03/08/2012 04:33 PM
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Re: [TN] Black substance






Hi Pat,

Got your pictures and have them posted. Sorry for the delay, but I'm still 

running in low gear. Here they are, and all I can say is YIKES!

http://stevezeva.homestead.com/whisker1.JPG
http://stevezeva.homestead.com/whisker2.JPG
http://stevezeva.homestead.com/whisker3.JPG
http://stevezeva.homestead.com/whisker4.JPG
http://stevezeva.homestead.com/whisker5.JPG

These look like the classic silver/copper corrosion from being exposed to 
reduced sulfur gasses such as hydrogen sulfide. Here's a good paper that 
details it all:

http://chavant.net/new_site/files/pdf/HP_ImAg_Corrosion_Paper_ISTFA_20061.pdf


I would be very scared, very, very scared...

Steve



-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Steve Gregory
Sent: Thursday, March 08, 2012 11:25 AM
To: [log in to unmask]
Subject: Re: [TN] Black substance

Hi Pat,

Reply to me with the pictures and I'll get them posted...

Steve

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Goodyear, Patrick
Sent: Thursday, March 08, 2012 1:39 PM
To: [log in to unmask]
Subject: [TN] Black substance

Ok got a new one.    Found on the plated portion of a turret a black fuzz,
also on the riveted backside and the plated portions of all of the lands 
outside the soldered areas.
It cleans right off with alcohol leaves no residue, is crystalline in 
structure and grows away from the metal has a coral like appearance.

I have attached pictures but Steve is off today so don't know who else can 

post.

Again a 40 year old board.

Any ideas????

Pat

.


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