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

From: Christian Fandt <cfandt_at_netsync.net>
Date: Fri Dec 17 08:45:38 1999

Upon the date 09:22 PM 12/16/99 -0800, Ethan Dicks said something like:
>
>
>--- Tony Duell <ard_at_p850ug1.demon.co.uk> wrote:
>> > > Do you have the 3 grey books for the ASR33? Volume 1 of the maintenance
>> > > manual covers lubrication.
>> >
>> > If I do, it's long buried.
>
>BTW, are these 8.5"x11" paper or 11"x17" paper?

8.5 x 11. If they are originals still in their binders then you should be
looking for medium grey-colored, 3/4" thick binders.

>
> What's the synopsis for the area around the
>
>> Well, the general idea is to clean and dry the type cylinder and the
>> hammer face...
>
>One thing that I did mention and I'll mention again is that my hammer face
>is not original - I stuck on a rubber sticky foot and I suspect that it is
>part of the problem. I read here recently that someone has had luck with
>carved pink pearl erasers, but I haven't tried that. Worst case is I can
>nab the printing mechanism out of my wire-service TTY, the one with the 110
>baud data set (modem) built into the pedestal. It doesn't fix this one, but
>it does get me up and running more quickly.
>
>The other thing that sticks is the line-feed mechanism. I can see the pawl
>on the back side of the ratchet at the left of the main roller and it doesn't
>always spring back up. Presumably it's another lube job waiting to happen.
>
>Neither of these teletypes has been stripped down in the 13+ years that I've
>owned them. To make matters worse, neither one has been powered on in ten
>years. I haven't had time to work with my classic machines until this year.
>
>> However, if it's actually sticking, then either something is bent or the
>> old oil is gumming it up (probably the latter). In which case _I'd_
>> dismantle the carriage totally, clean all the parts in a suitable
>> solvent, put it together and oil it.
>
>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.

EPA and various states have put the hammer down on "volatile organic
contaminants" used in industrial and consumer products and this may not be
an issue nowadays but read the label and make sure you don't do further
damage.

Myself, I use kerosene _out of doors_ to wash down most of the
non-rubber-touching components when doing a mechanical cleanup. You should
firmly attempt to keep it away from the distributor and other electrical
contacts. If you've got an air compressor, use a *low* pressure blowgun to
help get the kerosene mostly blown away. WD-40 can be used to wash down
parts but *don't* rely upon it as a lubricant. It is not!

>
>> 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
could have ever experienced for ourselves. Hardly 'misspent' :-)

>
>I used to disassemble sewing machines as a youth. I never tried putting them
>back together, but I'm OK with hand tools. I just repaired the works of an
>upright piano that I was gifted with - its problem was dried and cracked glue
>joints on one key mechanism and the entire damping bar. Obviously, a teletype
>has more moving parts than a piano, but there is a superficial resemblence.
>
>> > How many types/grades of lubricants are there for a proper lube job on a
>> TTY?
>>
>> 2 AFAIK. One is an oil. It's a light-ish (SAE 10 or thereabouts) engine
>> oil. I normally use the lighter of the 2 oils recomended for my Myford
>> lathe, as it's about right and I have an oilcan of it anyway. But any
>> light machine oil (NOT WD40!!) is OK.
>
>Sewing machine oil? "Three-in-one" brand general-purpose oil? Am I on the
>right track here?

Very good is a synthetic oil like that recomended by a retired ex-TTY
repairman. Sewing machine oil and 3-In-One both do not "dry out" hardly at
all and could be used. Here's a msg from the Greenkeys list I kept on hand.
Refers to the previous TTY generation Model 28's but it mostly applies to
33's too:

Date: Fri, 16 Jan 1998 23:14:08 -0800
To: heathkit_at_juno.com
X-UIDL: 885218092.751
From: Don Robert House <dhouse_at_abac.com>
Subject: [GreenKeys] Re: Maintenance of Teletype machines
Cc: greenkeys_at_qth.net
Sender: owner-greenkeys_at_qth.net
Precedence: bulk
Reply-To: Don Robert House <dhouse_at_abac.com>
Status: U

Danny,
You should lubricate the gears and bearings with a lithium grease and
lubricate all of the felts with oil. The felts should not be white; if
oiled properly they will be a gray or orange in color. I use One Lube by
the Slick 50 folks, it lasts a long time; 2nd choice, use straight weight
SAE 10 or 20 weight automotive oil. Use caution when lubricating the
selector clutch, be sure to keep the oil away from the selector magnet.
You can clean the selector magnet armature with bond paper. Petroleum jelly
works pretty good on the type box and print hammer rails.
Let me know if you would like any manuals on the 28 ASR.
Don
aka TTY MAN

>
>> The other is a grease. Just general-purpose high melting point grease,
>> like you'd use on a car (Oooops, modern cars don't have grease points
>> :-(). Castrol LM or something like that.
>
>I also restore Volkswagens. I know what a grease fitting is and how to
>operate a grease gun. (As an aside, I just got a 1975 Microbus in operating
>shape for $300 - it needs some work in the fuel injection system, but
otherwise
>OK).
>
>> If you can find the manuals, I can talk you through taking the carriage
>> out and apart (the manaul is not that clear in places). Without them it's
>> going to be more difficult, if only because of problems in refering to
>> parts (with the parts list I can use Teletype part numbers).
>
>Maybe someone will eventually scan a set it as was mentioned here.
>Alternatively, there is always the route of borrowing, xoxing and returning
>a set.

I've got a spare set you can borrow Ethan. We still have to continue anyway
talking about a 33 I have on hand and a couple other things we were
discussing several weeks ago and they can be sent along with.

The above lube info should get you started with bringing life back into
your 33.

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 - 08:45:38 GMT

This archive was generated by hypermail 2.3.0 : Fri Oct 10 2014 - 23:31:55 BST