22 Sep
2003
22 Sep
'03
12:23 p.m.
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
Do you have the reader PSU connected? This is a PCB in a metal box that
was often fitted in the stand. Sometimes it was fitted inside the
machine, on top of the 'call control unit' at the right hand side. But
if
your machine was removed from a stand, it's possible the reader PSU is
missing.
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.
OK, sounds as though the transmitter clutch is releasing, as it should
do. THen the contacts on top of the transmitter shaft (rear right
corner
of the 'typing unit', normally with white and black wires) should close
for every revoulution of the camshaft to energise the reader solenoid.
You might want to check these contacts (warning -- this is _NOT_
isolated
from the mains!)
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?
Get some 'plasic weld' or whatever it's called over there. It's
basically
dichloromethane (methylene chloride), and is a solvent for the plastic.
Put the broken bits together and run a brush dipped in said solvent
along
the crack. It'll disolve the plasic and fuse it together. if you want
to
make a really strong repair, get a piece of fabric (I am not sure what
I
used, ask your wife/girlfried/SO for an offcut of shirt, or something
:-)) and put it on the back of the join. Then brush more solvent onto
that and force it into the plastic.
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
This is pretty normnal. In the end you get enough up there for the top
bits to fall off and go down the tube. 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
Run it with the punch overhanging the desk and arrange some kind of box
under it. That's what I did with my first ASR33 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,
right?
It should print on just about anything....
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...
Get the ASR33 maintenace manuals (I think Al Kossow has them on-line).
About half of one volume covers lubrication. For 'oil' use something
like
3-in-1 or other light machine oil. For 'grease' use a normal high
melting
point grease like you use for general greasing on the car. 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
Yes, either a 20mA or 60mA loop (this is selecatable in the call
control
unit). Again you want the manuals. The pinout of any external connector
is _not_ standard, but the wiring to the barrier strip on the back of
the
call control unit is. That will be a big help.
Hang on, _6_ wires? That could mean you have remote reader control
(many
computer-interfaced teletypes had this), which could explain the reader
problems. Every manufacturer did this his own way, but they were
actually
all fairly similar, so if you get the docs for one (the DEC one is
probably the easiest to find), it will help in figuring out any mods
you
have. 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
It prints lowercase characters as uppercase (basically, it ignores bit
5
for letters IIRC). It sends all characters as upper case from the
keyboard.
The punch and reasder correctly handle all 8 bits, though, so you can
copy a tape with upper and lower case characters (or, indeed a binary
program tape) without problems.