"bz" wrote in message
. 139...
"Dan Dubosky" wrote in
:


"mike" wrote in message
news:tUg8k.29$od.22@trnddc07...
It's not just the water. it's the other stuff that's already on the
board.
Flux residue, electrolyte leaking out of caps, glues used in the
assembly process. Whether or not the final inspector belched on it,
Whether the cat peed on or near it. I'm gonna go out on a limb and
suggest that water is never the problem. It's what is in the water
that causes the grief. Water just ionizes it and makes it mobile.

--
Good point, Mike. There may have been something on the cell phone board
that was not on my experimental board. I did however scrub the cell
phone board twice with Radio Shack Electronics Cleaner and I think that
there is still some effects left from the submersion. I only did the
experiment since I thought that some were suggesting that there was some
corrosive residue created by the material in the less than pure water,
but they may in fact have been referring to residue materials of the
type that you have suggested.

It is likely that some SMT components or other components still have
conductive residue between the part and the board.

I 'repaired' a laptop computer that had 'merlott' [wine] spilled in it.
It was left powered on over the weekend.

The repair consisted of
remove power sources
disassembly
Rinse with plenty of clean water
rinse with alcohol
scrubbing and scraping to remove visible conductive paths. rinse that area
with water and alcohol.
rebuilding a couple of conductors that had been eaten away
completely drying. Many hours of sitting in the flow of warm, dry air from
an air vent. The keyboard took a long time to dry.
reassembly.






--
bz 73 de N5BZ k

There's a board that I repair commercially, that comes from an automatic
drinks vending machine. Often, when I receive them, they are caked in
ingredient residue that has been flying about inside the machine, which
makes them pretty much impossible to work on, so the first thing they get is
a wash. I just run the water until it's coming out of the sink tap (faucet
for our U.S. colleagues ?) at its hottest, squirt a little ordinary washing
up liquid on the board, flick some of the hot water on with a pan-scrubbing
brush, and then work that up into a thick lather, scrubbing between the legs
of the through-hole components. When it's had a good scrub, it gets run
under that hot water stream, until all of the soap is off both sides. It
then gets shaken, patted dry on a dish towel, before being stood vertically
in front of an electric fan heater for about 5 minutes.

The result of all of this is a board that looks like it has just come out of
the factory, and I have never had any future problems with any residues, and
I've been doing it to this particular job for about 6 years now. As well as
through-hole components, this board also has many s.m. components on it,
including both I.C.s and passives. It does not, however, have any 'closed
in' components such as coils, IF transformers etc, which as someone else
suggested, would probably not take kindly to being flooded with water ...

Arfa