10 Jul
2007
10 Jul
'07
11:05 p.m.
On Tuesday 10 July 2007 21:10, dwight elvey wrote:
These didn't do the "silver turns black as in oxidation or sulfide" trick
(I've seen that before). These legs were were simply rusty (as in iron oxide)
From: Lyle
Bickley <lbickley at bickleywest.com>
---snip---
Factoid: Many TI chips produced during 1975-77
period had very thin "legs"
and
poor tinning. When they were wave soldered, the solder offered them
protection. However, when they were socketed (as in the MODCOMP) they had
very little protection from the environment. They would rust and
eventually fail.
---snip---
The problem was that the outside was the silver plating ( the blackened
color is the
oxidized silver ) and the material inside would react electrolytically and
rot out
with even the slightest dampness. I've seen them where the only material
left was the plating. The slightest touch and the leg would just be gone :\
Dwight from top to bottom. The effect was similar, however.
Lyle
--
Lyle Bickley
Bickley Consulting West Inc.
Mountain View, CA
http://bickleywest.com
"Black holes are where God is dividing by zero"