removing parts from PCBs

[Paul Koning]

>>>>> "Allison" == Allison  <ajp166 at bellatlantic.net> writes:

 Allison> The real problem with water is not it's conductivity.  High
 Allison> power tube transmitters have used distilled water in the
 Allison> past as it's a really poor conductor if kept clean.

 Allison> DEC experimented with water cooling too. The Aquarius
 Allison> project was a water cooled VAX.  Too many headaches with
 Allison> leakage, heat transfer to the environment and installation
 Allison> issues.  Systems like that use a chiller and heat exchanger
 Allison> to cool the closed loop water system.  Those are costly and
 Allison> difficult to install.  Murder if it should leak in a
 Allison> computer room. Then there is an efficientcy problem as you
 Allison> end up using power to move heat which adds heat..

 Allison> With all that, the circuits they were trying to cool were
 Allison> getting more power efficient.  So by time they worked out
 Allison> wet cooling air cooling was again attractive or at least far
 Allison> easier.

I remember that episode.  The result was "Aridus" :-), now known as
the 9000.

 Allison> It's still packaging.  ;)

Yes.  And if your circuit density isn't all that high, air cooling
works fine.

That's why Cray actually had to solve these problems, and did back in
the early 1960s (CDC 6600), because he DID build things that could not
sanely be cooled any other way.

I don't ever remember hearing of leak problems in our Cybers...

    paul