11 Apr
2015
11 Apr
'15
8:46 a.m.
On Apr 11, 2015, at 8:12 AM, Noel Chiappa <jnc at mercury.lcs.mit.edu> wrote:
There is a product, can't remember the name. It's basically dental floss for
dentures, and comes in individual strings about 3 inches long with a cleaning tip at one
end.
I've used it to clean the individual internal key contacts on an HP25 calculator,
going in through a key way for each key after a battery leak with verdigris corrosion.
Took a bit of patience, but very effective...
> contact
blocks and the PCB, to clean it out.
Hi, all, thanks for all the suggestions: alas, they won't really help with
this part of the problem, since the gap between the PCB and the pin contact
housing blocks is only about 1mm (less in some cases) and there's no way I
know of to get any kind of effective brush into a gap that small.
Maybe something akin to dental floss, but that would be about it. (String
might be a good idea, it has a rougher surface and might be better at removing
impacted grime, plus it's wider, so will do more width on each pass.)
The Simple Green might be something useful to add to the bath, though. I
generally use compressed air to dry boards (although I've heard rumours of
possible static problems from this, I've never had a problem), which is easy
for me since I have a 5HP compressor in the basement. It mostly blows the
water (along with any dissolved minerals, although I usually try and finish
with a douse of distilled) right off the board.
From: Tothwolf
There /is/ actually a source for replacement gold
fingers (and copper
trace material), but that sort of stuff can get expensive if you need
to replace a lot of them.
Actually, I wouldn't try and replace the traces; I'd just use wire, and solder
the ends onto the remains. (I'm more into functionality than cosmetics. If
anyone is really intense about the cosmetics, please let me know, I'd be
interesting in hiring you to fix the two boards... :-)
The gold contact fingers are another matter, and for them I thank you for
your very useful pointer:
You might try contacting http://circuitmedic.com/
and see if they have
any replacement gold fingers the correct width.
I have yet to look into this, but I'm sure they'll have something that will
serve. The standard DEC contact fingers are 2.2mm wide, but some off-brand
boards use fingers as narrow as 1.6mm, so I expect they'll have _something_
I can use.
Noel