Or had open containers of soaps nearby, or stacked rubber or paper, or.....
But, after all, if that is all that grew on an old RMA CCA after 40 years, well, not so bad, really.
They should be able to be cleaned up, touched up, wash, clean, coat, and ready to go for another 40 years of service.
________________________________________
From: TechNet [[log in to unmask]] On Behalf Of Woolley, Mark D. (Mark) [[log in to unmask]]
Sent: Thursday, March 08, 2012 4:49 PM
To: [log in to unmask]
Subject: Re: [TN] Black substance
My first thought was silver sulfide.
Were the PWBs stored in a high sulfur gas area? Nearby a tire factory,
oil well or refinery, ot coal fired power plant?
mark
mark
Mark Woolley |PTRL Laboratory | Avaya | 1300 West 120th Ave |
Westminster, CO 80234 USA |
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Steve Gregory
Sent: Thursday, March 08, 2012 3:33 PM
To: [log in to unmask]
Subject: 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_2006
1.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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