Anyone any insight on this. Failure of 34 year old TTL chip, in
unpowered storage. Just 1 of 50 chips on a board, TTL,4000, analogue,
memory etc.
Only this one had silver tarnish looking appearance of black silver
sulphide on the pins. This make of TTL did for a while have silver
plating aded to the pin frame , for a period.
I cracked open the device and no obvious tarnish on internal frame
metal. Anyone know what the failure process was? was silver plating
found to be problematic?