Reviving and connecting an ASR33

From: Ian Primus <>
Date: Sun Sep 21 20:42:16 2003

Yesterday, I got an ASR33 teletype machine. So far, I have cleaned it a
little, checked that everything seems to be oiled well, and fired it
up. It seems to work well. All the characters print, and the type seems
clear, although I need to clean the type assembly. The rubber hammer is
still intact, but it is very soft, almost like a blob of silly putty.
It held up well enough for testing, but I will soon replace that with a
rubber foot as someone else on the list suggested. The tape punch seems
to work fine too, I don't have any paper tape, so I trimmed some
computer paper into strips for testing. I am having a couple of
problems with it though:

The paper tape reader doesn't seem to work. There is also a good chance
that I don't know how to operate the paper tape reader... I punched a
strip of paper with a string of text, then put it into the reader, and
threw the switch next to the reader into the "Start" position. The
teletype makes a lot of rattleing, but the tape doesn't run through the
reader, and nothing prints.

Some of the keys are cracked. A couple of the keytops have cracked out
from the lettering, most notably the "Break" key, which gets stuck down
because it is now slightly wider.

The space bar sticks a little, and occasionally gets stuck down. Not
far enough to jam, but far enough that hitting it again won't make a
space, but typing other keys seems to jiggle it loose. It's like the
spring or whatever recoil mechanism is loose or broken.

The paper advance knob is cracked. I think I can glue it, but otherwise
I will need to track down another.

The cover is cracked, but that isn't really a big deal. I should be
able to glue it back together. What type of glue is recommended for
teletype plastic? Just regular wacky glue, or some sort of epoxy?

The paper tape punch has quite a buildup of chad above the punch. It
doesn't seem to be going down into the black tube at all. Is this
normal? Also, what can I do about the chad, since I don't have the
stand. I have the chad box, but I can't really attach it without the
stand. I'll probably end up building something for it, or maybe
propping it up with some blocks of wood so I can fit something under
there, but weren't there desk models of the ASR33? What did they do
with the chad?

I also have some general teletype questions:

What can I use for tape? I have access to a very powerful paper cutter,
the kind that can cut a ream of paper cleanly in half. Can I just take
some junk fanfold computer paper and cut it into strips? I know that
some paper tape was fanfold like that, but I don't know if the
perforations would tear apart too easily or not

Likewise, what can I use for paper? Right now, I have just been loading
single sheets of computer paper in, but I should just be able to remove
the tractor holes from fanfold computer paper and run that through,

Is the teletype capable of moving back a space? "Rubout" doesn't move
the print head back, but I don't know if it should. I know the teletype
can't erase, but I don't know if it can move backward.

Where should I oil the mechanism? Right now, everything looks OK, but I
should probably lubricate it someplace periodically, right? Similarly,
what sort of oil should I use? Just regular household oil, or something
lighter/heavier? Obviously not WD-40, however...

What's the best way to clean the type cylinder? It is pretty dirty, but
I am almost afraid to take it off to clean it, lest I get it on crooked
or backward. I know I have cleaned the type bars on typewriters by just
using an old toothbrush and some toothpicks to get the gunk out of the
"O", etc. I would assume the same principle applies here, too.

The platten is pretty hard. It works, but is there a way of replacing
it, or maybe a way of reviving the rubber? I have heard of people
reviving the plattens on old typewriters with some method. It's
probably more trouble that it's worth, but I would like to hear what
people have to say.

And, of course, the inevitable question, how do I connect it to
something? It has a cable fitted to it which I understand should be a
current loop interface. It is a funny little six pin rectangular
connector. I have found information on how to connect current loop to
RS-232, but what pin does what? Was there a standard? I would very much
like to be able to plug the teletype into a UNIX box or something, or
maybe the Prime, but for any of those, I would need RS-232. Also, since
the teletype can only print upper case, how does it render incoming
text? Does it just ignore all lowercase characters, or does it print
them uppercase? Does it send all uppercase or all lowercase? I have a
Teleray terminal that renders all lowercase characters as uppercase,
and uppercase as weird symbols, so I'm not sure what the teletype does.

Thanks in advance!

Ian Primus
Received on Sun Sep 21 2003 - 20:42:16 BST

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