And yet another, another weird corrosion story (not synth rel ated)

[Goddard, Duncan]

>>>As long as we're telling war stories....<<<

ok- remember the walkman I told you about? which was fine when I put it on
in the house but misbehaved as soon as I got outdoors? there is some
evidence that atmospheric contaminants can and will build up on pcb's and be
"activated" by moisture. in the short term, this can cause misbehaiour due
to stray capacitance/resistance across adjacent tracks.
where I used to work, we had a number of "aston" tv character generators
(this is on-screen text, not virtual actors!) which would crash
intermittently, or corrupt their text output. we tried everything- leaving
their covers off, with fans pointing into them, reseating cards, replacing
chips..... eventually, we discovered that some of the non-socketed chips
were suffering from tarnishing- the silver plating on the pins and through
the boards was going brown and causing some small volt drops. so we took
them all out and put sockets in, and instituted a programme of
silver-dipping the affected chips once a month.
this was in the west-end, with powerful air conditioning, the sort that
gives you legionnaire's disease. in a normal home-studio, the effect
probably takes much longer, but I've long-since ceased to be surprised by
the condition of circuit boards older than a couple of years......

d.


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