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From: Michael A. Terrell on 2 Aug 2010 13:08

GregS wrote:
>
> In article <WtCdnar_6NJbXcvRnZ2dnUVZ_gadnZ2d(a)earthlink.com>, "Michael A. Terrell" <mike.terrell(a)earthlink.net> wrote:
> >
> >"Paul E. Schoen" wrote:
> >>
> >> "William Sommerwerck" <grizzledgeezer(a)comcast.net> wrote in message
> >> news:i32gbp$hnm$1(a)news.eternal-september.org...
> >> >> 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
> >> >> 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.
> >> >
> >> > Interesting observation.
> >> >
> >> > Question... Wouldn't distilled water alone flush off ionic contaminants?
> >>
> >> Probably. But there may be some sort of oily residue that will be removed by
> >> the detergent. And hot water from the tap is much cheaper. It may be good to
> >> do a final rinse with distilled or deionized water. I have heard that some
> >> people stack their boards in a dishwasher. But my method works for me and is
> >> is very practical for small quantities.
> >
> >
> > We used a citrus based cleaner in a commercial board washing machine
> >at Microdyne. It was a modified stainless steel industrial dishwasher
> >with a separate solvent tank and fresh water wash. Then the boards went
> >into a board drying oven for 12 to 24 hours. This was for small runs of
> >boards stuffed and reflow soldered in house.
>
> I noticed citrus based degreasers leave behind oil.
> Thats a bad thing when you really want to paint something thinking
> it will work. Bad for tape sticking also.
>
> I think I allready mentioned mens room board cleaning.


Mention whatever you want, but it was a NASA approved process. We
built telemetry equipment for the aerospace industry. NASA wouldn't
approve of your method. We built millions of dollars worth of equipment
per year.
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