PDP-8/L and TTY stuff (was Re: TTY and current loop

From: Christian Fandt <cfandt_at_netsync.net>
Date: Fri Dec 17 15:23:58 1999

Upon the date 07:27 PM 12/17/99 +0000, Tony Duell said something like:
>> >I can get for under $15 a disposable carburetor solvent bath-in-a-can at a
>> >local auto parts store. Presumably, this is a suitable solvent. The print
>> >mechanism should fit nicely for immersion.
>> Whoah Nelly! This may not be good stuff to get near such equipment! There
>> could be solvents which harm the rubber/plastic/painted parts contained in
>> carb cleaner! I know toluene _used_ to be in Gumout brand carb cleaner back
>> when I often worked on old cars.
>That's why (IMHO) you should dismantle it fully first. Most solvents
>should be fine on the metal parts, but take care with plastic and rubber
>parts. I normally use propan-2-ol for those, as it doesn't seem to
>do any damage.
>For the metal parts, I either use Electrolube 'Electronic Cleaning
>Solvent' (which seems to be a hydrocarbon mixture but I am not sure), or
>white sprit (sold for thinning paint, cleaning paint brushes, etc in the

We call it 'mineral spirits' over here.

And propan-2-ol is called Isopropyl Alcohol over here. Use a lab grade or
at least 91% grade because the cheaper grades have high water content
(rubbing alcohol is one example, 70% H2O.) The water will make it rather
difficult to clean off the oils and greasy grime, etc. from surfaces.

>UK). If that doens't work, then petrol (gasoline) is a good decreasing
>solvent, if used with care, outside, away from any source of ignition.
>Obviously, only use any solvent in a well-ventillated area.

There is a degree of toxicity with gasoline regardless if it is now
lead-free. Don't let it be absorbed thru the skin and don't breathe too
many vapors!! Use it only if you have to.

>> EPA and various states have put the hammer down on "volatile organic
>> contaminants" used in industrial and consumer products and this may not be
>Yes, a pain, isn't it. I am not at all convinced that the replacements,
>especially considering the extra quantities I have to use to do the same
>job, are any better for the environment.
>> >> I did my first teletype without the manuals, but unless you had a
>> >> misspent youth like me dismantling and reassmbling everything in sight,
>> >> I'd not recomend it... With the manuals it's not too hard if you're
>> >> generally OK with hand tools.
>> Well Tony, that's the best way to self-learn mechanical techniques that we
>It's the _only_ way :-)...
>Sometimes I wonder if the reason why I can still fix things is that I am
>NOT a 'factory trained technician' or anything similar. I've _had_ to
>work out how things work and how to adjust them from first principles in
>a lot of cases. Which means I am not likely to get confused by some case
>that wouldn't have been covered in the 'training'


>> could have ever experienced for ourselves. Hardly 'misspent' :-)
>Hang on... Are you saying the fixing things yourself without the manuals
>is a way for you to learn how to do it, or that _me_ fixing my stuff
>leads to me posting how to do it here? The former is certainly true. The
>latter, well....

Yes, I'm saying the former is true. I am refering that the time was *not*
misspent when you, me and others here simply rolled our sleeves up and dove
into a problem if there had been no technical reference available.

Regards, Chris
-- --
Christian Fandt, Electronic/Electrical Historian
Jamestown, NY USA cfandt_at_netsync.net
        Member of Antique Wireless Association
        URL: http://www.antiquewireless.org/
Received on Fri Dec 17 1999 - 15:23:58 GMT

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