[GreenKeys] auto cr/lf

[Eugene Hertz]

Wow! Thanks for the explanation. I will take some time to digest and poke around. Amazing, these machines are. Question on the overstrike.  Right now when I send a CR to the printer, the carriage returns but I do not automatically get a LF.  Does this mean that the art requiring overstrike will work properly? Your explanation seem to indicate that a CR sent to the printer should do nothing at all if I have that right.

On the auto CR/LF - this will take me some time to hash out.  I will probably set one of my machines (either the ASR or KSR) for this and leave the other with the auto so I can copy both.

Thanks again. I hope I can follow along!

While I have some folks attention, I am still looking for a little "h-shaped" lever that resets the reset bail on the 28ASR typing reperf. Part number is 159880. It is lifted by the cam on the K/KT/T knob.

Please let me know if you might have one of these.
thanks!
Eugene 

-----Original Message-----
From: WA3FRP at aol.com [mailto:WA3FRP at aol.com]
Sent: Sunday, August 20, 2006 09:20 PM
To: ehertz at tcaf.org, greenkeys at mailman.qth.net
Subject: Re: [GreenKeys] auto cr/lf 

Eugene,

Two things may be involved here: Non-overline and auto CR/LF. 

If the problem occurs on ever line regardless of length, you need to remove or disable non-overline. You can usually do this by swapping the universal codebars in slots 5 and 38 of the stunt box. See details below for particulars. 

If "Miss Sweden" is longer than 73 characters long in some places, then automatic CR/LF also needs to be disabled. You can easily do this by removing the "bit from the horse's mouth" - also know as mod kit 157514. Look at the right side of the line printer above the piston used to slow the carriage when CR is selected to the spacing drum – the round metal object that slowly turns as the carriage spaces across the page. The description is below. Simply remove the screw and the "bit" and automatic CR-LF will be disabled.

Now the details...


 What is Non-overline?

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 text.

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 paperWith 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 the machine.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 all power).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 benefits.

What is Automatic CR/LF?

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 it’s there -- fine.If it’s not there, contact me for 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 – the round metal object that slowly turns as the carriage spaces across the page.Using a lot of light, look at the 12 o’clock position, through the top inside of the spacing drum to see something that looks like a horse-head.There could be something in the horse’s 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 don’t 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 153916..

When you have the needed parts, start the installation by adding mod kit 157514 to the “horse’s mouth”.

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 at the www dot rtty dot com website. This will take a while to download.Page 12 of 20 has a good picture of the code bars.

If you don’t 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 finished. 

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 don’t 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.


73

Russ WA3FRP