Board Cleaning Opinions Wanted

From: Gary Oliver <go_at_ao.com>
Date: Tue May 11 17:01:25 1999

At 04:54 PM 5/11/99 -0400, you wrote:
>On Tue, 11 May 1999, Jeffrey l Kaneko wrote:
>
>> Thanks to everyone who offered advice; something I was thinking
>> was to use warm water, and some dishwashing liquid. Does that
>> seem safe?
>
>Maybe, maybe not, depends.
>
>Why is it that most of the manufactueres used something like if not a real
>dishwasher that every one is scared off here?

In fact, for the small runs of things we do at my business, we DO use
an old "portable" dish washer...

But the important thing to consider is: what was installed AFTER the
last aqueous board wash? For example, some older capacitors, and a
lot of old switches, pots, etc., could not be washed in such a manner,
as the water/detergent would find it's way inside these parts and
contaminate the "delicate bits" therein.

For "normal" hand-assembled boards (small runs) that get washed in
the old "Kenmore," we use a solder (and possibly a spray-on) flux
which includes its own "detergent." That way it becomes a cleaner
in the dish washer. We add nothing to the machine during the wash
except good, clean water.

You do need to be reasonably careful about getting "good" water
to the machine. With modern CMOS circuitry, the conductivity of
the trace minerals left on boards from "normal" house water can reduce
the resistance enough to cause failure of the board, where it would
have gone unnoticed on the older nmos / ttl boards.

>
>My experience is with more than several hundred s100, multibus, Qbus,
>Omnibus and misc non-bus cards over 20 years of doing this it's never been
>a problem other than to insure the water is completely dried off the
>board. This does not include my expereince with marine equipment that has
>had a swim in salt water (hint salt eats boards!).
>
>> I'll leave the corestacks alone (well, I'll use a soft brush to
>> remove the dust from the *outside* of the 'sandwich').
>
>The core stacks themselves if there were even a hint of something nasty
>on them they'd get washed carefully, it's the fine wire I worry about.
>Generally the sense and driver boards are ok to machine wash.
>
>Allison
>


Gary
Received on Tue May 11 1999 - 17:01:25 BST