Re: Super Serial trouble.

[russotto@wanda.pond.com (Matthew Russotto)]

In article <3b39d201@news.iprimus.com.au>,
Mark Cummings <NOTfigjams@primus.com.au> wrote:
>> Another thing, this board was terribly dirty so I cleaned it with
>> denatured alcohol (or is "white spirits" the correct English term? You
>> know the stuff you aren't supposed to use for lighting charcoal for
>> your barbecue, but most people do it anyway.)
>
>One of the correct solutions used for circuit board cleaning is ISOPROPYL
>ALCOHOL, we use it at work for exactly that purpose. This is 7% Alcohol by
>vol, I don't know about the rest though, mostly water ? White Spirits leaves
>a residue as far as I know. I have also seen some techs use Acetone, but I
>would be very wary of that, as it can eat into the fibre glass resin.
>Personally I have never tried Acetone for this purpose.

Isopropyl alcohol comes in various concentrations.  7% is not what
you'd use for cleaning boards.  70% maybe, but I prefer 91% or
better.  And yes, the rest is nearly all water.

>6% sounds about right. the real trick is the technique and the drying. First
>remove all the components that are socketed. Start a tap with warm running
>water, clean the board first with lots of ISOPROPYL ALCOHOL with one brush
>until its running reasonably clean with minimul flux (the brownish gunge
>left on some boards). Then add plain dish washing liquid and a long soft
>brissled brush, circling around all sockets etc. Add a little water to soap
>it up.

You do not want to do this.  You can clean a board with no components
or sockets with water, but you do not want to do it with a board which
does have components.  Water will get trapped and cause problems.
Pins and sockets will corrode.

>get all traces off the board. Check the board for traces of soap/flux. Flux
>appears as a kind of oil stain or snail trail.

Flux of that vintage can't be removed with any common solvent (I've used flux
removers, but they're probably all banned by now.  In any case, flux residue
is harmless)
-- 
Matthew T. Russotto                                russotto@pond.com
"Extremism in defense of liberty is no vice, and moderation in pursuit
of justice is no virtue."