25 Apr
2017
25 Apr
'17
2:08 a.m.
On 4/25/2017 1:39 AM, Pete Turnbull via cctalk wrote:
"Little residue" would be more accurate, and some of that residue will
be water (look up "azeotrope") - plus you need a lot of alcohol for
something the size of a PDP-8 backplane. Blow dry, even after an
alcohol rinse. In the process of cleaning optics indeed you need air and other
means to
do that, you are right. But in this case I'm suggesting the alcohol as
a way to displace water out of internal parts. The spotting or such is
not much to worry about in the cleaning job on a computer part.
But in optics the process is much longer and elaborate, but still needs
the ventilation to be sure you don't have a problem with fumes.
We had a booboo in assembly that required cleaning and we no longer had
freon cleaner we wanted to use in that quantity, so we went with the
water / alcohol process. A switch had defective sticky seals on it and
they had all gotten waterlogged. Vendor claimed they would survive
water process wash and they were wrong. Paid us quite a bit in credit
for messing up a couple hundred boards before we caught the problem.
Solution was to rewash in water then alcohol rinse.
thanks
Jim