"GregS" wrote in message
...

I also remember fellow in our section, working on something new, computer
"terminal monitors". There was some kind of problem, and he was taking
some
boards into the mens room to wash them off. i guess they worked after
that.

Long ago (1980?) I remember having problems with leakage on a board that
stored voltages in polystyrene capacitors using CMOS switches and op-amps,
but the voltage would bleed off too quickly to be useful as a "memory". We
tried all sorts of flux removers and it still didn't work well enough. But I
had an idea that it might be ionic contaminants such as salt, so I took a
board into the mens room and scrubbed it with hand soap and flushed it with
hot water. Then I dried it with a heat gun, and "voila" it worked like a
champ rather than a chump.

I have had good results with isopropyl alcohol as a flux remover, applied
with a stiff "acid" brush with bristles cut short. It does leave a white
residue. But then I follow with a spray of detergent, scrubbing once again,
and the heat gun to dry it thoroughly. You need to be careful about
overheating, so I hold the board by hand on the edges and move the hot air
around. My fingers will hurt before I overheat the board. Seems to work very
well.

Paul