Re: Super Serial trouble.

["Mark Cummings" <NOTfigjams@primus.com.au>]

> 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.

You may be right, I havn't read the label for a while. Maybe it's 7% pure
alcohol, but the number 7 is in my head, must check again.

> >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.

This is why you need to blow dry it, as I stated at the end of my post. And
this is the technique that we are trained to use at work. Using an
electronic cleaning spray will dispence anything that was missed by blowing
dry. The only other althernative is to soak the whole board in a tub of
alchohol then blow dry. Often several tanks of varying levels of clean
alcohol are required for this. Each one becoming cleaner. This is not
practical for most home users as it consumes litres of alcohol and normally
requires a good ventallation system to avoid being overcome by the vapours.
If you could get de-mineralized water, that would be preferable to tap
water, but again you will need a lot of it to rinse off the soap.
There really is no other way to do it. If you only have a blank board and
add the components, you get flux residue which for a full board will take
days to remove by any other means.

> 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)

not true, even the flux inside most 60/40 solders will become corrosive in
high temperatures. Flux by it's very nature is corrosive, that's how it
works in chemically cleaning the metal tracks of a circuit to make solder
stick better. Fortunately I have never found a flux that will not remove
with ISOPROPYL ALCOHOL and brushing. Sometimes soaking for hours is
required, but they all come off eventually.

Mark