PeterD wrote:

On Sun, 25 Feb 2007 20:55:11 GMT, Al wrote:

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

RoHS solder has already shown itself to be substandard in this
respect, and we'll be seeing lots of these failures as the standard
becomes the rule in the rest of the world. Course, Europe will lead
the way in broken electronics gear!

Now that was done to reduce 'hazardous' materials in the disposal
chain. Wait... So now they throw away *more* stuff because it breaks
more quickly? That's efficiency?

I'd also like to know if "tin pest" has started happening. I guess the
first place to check would be some cold country because it's supposed to
happen below 13 degrees C.

Chris