Altair Turnkey and some DEC stuff cheap

Roe Peterson roeapeterson at gmail.com
Sat Apr 11 10:46:21 CDT 2015



On Apr 11, 2015, at 8:12 AM, Noel Chiappa <jnc at mercury.lcs.mit.edu> wrote:

>>>  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.

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...



> 
> 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


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