[Premium-Rx] lead free solder tin whiskers

[Mike Andrews]

On Mon, Jul 23, 2012 at 01:33:24PM -0600, Gary Geissinger wrote:
> If you exercise the circuits on a regular basis even with CMOS you stand
> a good chance of clearing the shorts. The tips of the whiskers are
> microscopic.
>
> But if you don't run the circuits for a long time the shorts won't clear
> even with significant current. Some geosynchronous satellites were lost
> this way a few years ago.
>
> This is an argument against "cold sparing". It reminds of issues with
> electrolytic capacitors. It pays to "fire up the boat anchors" every once
> in a while.

This is in no way a new issue; I remember a back cover picture in an Analog
SF magazine, back in the late 1960s or early 1970s, which was an SEM image
of tin whiskers. The accompanying article speculated on the problems of
long tin whiskers in electronics.

-- 
Mike Andrews, W5EGO
mikea at mikea.ath.cx
Tired old sysadmin