In article ,
Michael wrote:

Al wrote:
(snip)
The problem is with temperature cycling. The solder joints eventually
fracture and lead to either intermittents or opens. You can really
stress you electronics by letting it cold soak and then turning it on.
It may not fail immediately, but you have shortened its life.

Al


You make an excellent point, Al, that nobody else here brought up (as far as
I've read). Thermal cycling stresses solder joints. Period. Repeated
stress
eventually causes strain (damage). Period.

In a former life I was an engineer in Packaging Assurance at a major U.S.
business machine company. Our life projection testing included thermal
cycling
in the range 0C-100C specifically because thermal cycling produces stress and
stress precipitates strain ... i.e. component failure.

So exposing e.g. your laptop to thermal cycling - be that room temp. - hot
car
- room temp. or room temp - cold car - room temp - is decidedly a Bad
Thing. Maintaining your electronics at a *constant* temperature during its
entire life is impractical but would go a long way toward extending its life.

Then again, who really cares if a laptop dies after only a couple years?
Within
that relatively short period of time it is superceeded, at least twice, by
newer-faster-better.

So says this guy, who still uses a PC-AT, a vintage 1993 80486-20 laptop, and
a
vintage 1998 Pentium II-350 desktop PC.

And I did component failure analysis at a major defense contractor. I've
seen it too many times. And another one was tin whiskers between solder
joints. ;-) Can't wait to see what happens with the new lead free
solders. It'll be a bonanza for us failure analysts.

Al