MODCOMP II Revisited...
lbickley at bickleywest.com
Wed Jul 11 01:05:00 CDT 2007
On Tuesday 10 July 2007 21:10, dwight elvey wrote:
> >From: Lyle Bickley <lbickley at bickleywest.com>
> >Factoid: Many TI chips produced during 1975-77 period had very thin "legs"
> >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.
> 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 :\
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 top to bottom. The effect was similar, however.
Bickley Consulting West Inc.
Mountain View, CA
"Black holes are where God is dividing by zero"
More information about the cctalk