Try it!!!! (Was - Re: One More PCB Dishwasher Question)

From: William Donzelli <aw288_at_osfn.org>
Date: Sat Dec 29 16:04:53 2001

> If you consider 65f to 145f heat shocking significant then whatever
> you do don't turn on your PC. Seriously, that is not enough temp
> change and cycles, common temp shock testing {operating} is
> freezing water to 158F water {+70C} for many (usually hundreds
> of cycles). Usually the upper temp is not the operational limit but,
> the storage limit (in the 150C {300f} range!). Never minding what
> wave soldering a 16pin dip does in a room temp to molten solder
> step!

The key is TIME. 65F to 145F is not that big of a jump, but when it
happens in about a second - well, that is a pretty good rate of change.
dT/dt and all of that stuff I don't remember how to do anymore.

When I turn my machine on, certainly some parts go from room temp to
something pretty hot. It, however, is a nice smooth, slow climb. The
processor probably gets hot really fast, but I am sure the designers had
that in mind for such a power hog. What about the other chips that never
use that much juice to get hot? I am sure they do not appreciate such a
sudden rise in temperature.

William Donzelli
aw288_at_osfn.org
Received on Sat Dec 29 2001 - 16:04:53 GMT