|STUNT BOX MATERIALS for Teletype Model 28
and Model 35 Submitted by David Christ K0LUM1)
General Description 28 SB Issue 1 (c) 1959 Teletype 28 Stunt Box in color 20 pages. Description of how the stunt box works. 13.7 MB
ULTIMATE Model 28 Teletype Stunt Box Booklet - 28stuntBox001
2) 28LP Technical Data Sheet Issue 2 (c) 1959 Send-receive and Receive-only Page Printer Sets 2 color 8 pages. Descriptions of various models and options available. Explanation of model codes. Comprehensive listing including pictures of all parts available for stunt boxes. 4.8 MB
Great Set of Model 28 Page Printer 8 page glossy Data sheets - 28LP001
3) Handwritten note from Len Jaguilo on Teletype Corporation note paper attached to item 3. Additional information on selective calling. Undated 152 KB
Teletype Model 35 Selective Call Cover Note - SelCallcovernote001
4) Application of the Model 35 Page Printer to Selective Calling. Memo dated August 9, 1963. Copy of 2 page typescript. 995 KB
Teletype Model 35 Selective Call Model 35 printer to Selective
Calling - 35SelCall001
5) Selective Calling Without Using the Zero Code Bar. Memo dated 3-27-63 Copy of 4 page typescript. 1.8 MB
Teletype Model 35 Selective Calling without the Using the Zero
Code Bar - NonzeroSelCall001
Non-Overline and Automatic CR/LF for the
Teletype Model 28
Non-overline fixes that annoying problem when your Teletypeís
carriage comes back and overprints a perfectly good line of text after
receiving a carriage return but no line feed.
Automatic carriage return / line feed fixes the problem where
your Teletypeís carriage continues to print at the extreme right hand
side of the platen.
- Non-Overline for the Teletype Model 28
On a normal Teletype machine, when someone hits CR, the
carriage will automatically come back but will not turn up a new line.
This is a nice feature for RTTY Art but a real problem if you are trying
to copy a weak signal and you are already receiving partially garbled
Fortunately, the Model 28 machines can be easily converted
to avoid overlining. This change requires no new parts and can easily
converted back to factory stock in a few minutes.
Here are the steps to make the change:
- Remove the roll of paper
With the motor running, look at the top of the stunt box.
Hit the CR key and some slot will show activity. This
should be slot 5, counting from right to left as you stand in front of
- Hit the LF key and two slots should show activity. These should be
slots 38 and 40, counting from right to left as you stand in front
of the machine.
- Leave slot 40 alone.
Remove the LP and take out the stunt box (after disabling
Swap the universal code bars in slots 5 and 38 and
reassemble the machine.
Now, when the CR key is pressed, nothing happens. When
the LF key is pressed, both CR and LF occur at the same time.
You will still have to hit the CR key when you are
transmitting. The CR character still needs to be sent to the distant
machine. It may seem awkward to type the CR key and have nothing
happen. But, the simplicity of this change, the fact that no
additional parts are needed and that it works so well are huge
- Automatic Carriage Return and Line Feed
The first step is to check to see that the "0"
codebar is already installed. Most, but not all, Model 28s have this
feature installed. You can easily check this by looking under the left
ribbon spool. There should be 9 code bars and the second from the bottom
should be labeled "0". If itís there -- fine. If itís not
there, you will need the parts kit needed to add this feature.
Next, look at the right side of the line printer near the
piston used to slow the carriage when CR is selected. Look through the
spacing drum Ė the round metal object that slowly turns as the
carriage spaces across the page. Using a lot of light, look at the 12 oíclock
position, through the top inside of the spacing drum to see something
that looks like a horse-head. There could be something in the horseís
mouth. If it looks like a bit, then you already have mod kit 157514
installed. If not, you need mod kit 157514 installed.
Next check to see if stunt box slots 4 and 39 contain
parts. You can check this in the same way that you checked for motion
when installing non-overline. Remember, the slots count from right to
left when standing in front of the machine. You probably donít have
anything in these two slows and will need to obtain two uncoded function
bars, part number 153440 and two sets of slot parts, part number
When you have the needed parts, start the installation by
adding mod kit 157514 to the "horseís mouth".
This will take a while to download. Page 12 of 20 has a good picture of
the code bars.
The next step is to remove the stunt box and add the parts
to slots 4 and 39. Before you do this, you will need to code the uncoded
code bar by breaking off all of the tines except for one. This is going
to look like a very strange code bar when you are finished. The one tine
that remains is in the zero level, non-selected position. There is a
good picture of the function bars and how they are coded along with an
overview of the stunt box in the Teletype brochure that you can find
If you donít have access to this document, break off all
ten tines at the top of the code bar and three of the four tines at the
bottom of the code bar. The one tine that remains is in the upper right
quadrant of the four tines that are clustered together.
Once you have the slot parts and the code bar installed,
and the stunt box and LP are all back in place, the checkout is pretty
easy. First confirm that spacing over to the extreme right hand margin
causes an automatic CR and LF. Then go back and count the exact point
when this occurs. By standard, you should get 73 characters on a line an
automatic return on character 74. If this is set correctly, you are
To adjust the return character, locate the spacing drum and
the five bolts holding the front and rear rings to the spacing drum.
Going clockwise, you will see that the first, third and fifth are all
round-head bolts. The second and fourth are hex-head bolts. You have to
slightly loosen, but not remove, the first, second, third and fifth
bolts to adjust the right hand margin adjustment. .Take a screwdriver
and slightly move the rear ring that is attached to the spacing drum.
Move the ring counterclockwise to lengthen the line length. You donít
have to move the ring very far so go slowly. Temporarily tighten the
bolts that you loosened and try the line length test until you get the
desired line length.
Submitted by: Russ -