29 Dec
2001
29 Dec
'01
3:06 p.m.
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!
For the average dishwasher that would likely be only one cycle
of the 65-145F span as well.
Again if your really that worried, don't. Reality is that anything
that woud be that fussy is really fragile. The only examples of
something I'd worry about down RI there is the PDP-12 a(maybe)
and definatly the PB250{uses germainium transistors with low
Tstorage and operating range, delay lines and other rare items}.
Even then my viewing of both of those is they were very clean
and not likely at issue.
Allison
-----Original Message-----
From: William Donzelli <aw288(a)osfn.org>
To: classiccmp(a)classiccmp.org <classiccmp(a)classiccmp.org>
Date: Saturday, December 29, 2001 3:05 PM
Subject: Re: Try it!!!! (Was - Re: One More PCB Dishwasher Question)
Not an issue
as the temps are well blow boiling (nominal 145f).
You missed the whole point. A sudden change (as in a second or so) from
65 F to 145 F will shock a chip far more than a gradual change (15
seconds) from 65 F to 212 F. It is the rate of change, and not the
change itself, that matters. With hot water hitting the chips instantly,
the rate of change is going to be *really* fast. It may also be uneven -
if a large chip only gets half soaked with the hot water at startup.
William Donzelli
aw288(a)osfn.org