[GreenKeys] Lorenz Lo15 - advice request!

Fri Jun 21 10:18:30 EDT 2019

We had two Mod. 19s and 3 or 4 Model 28’s.  On manual operations, we were ‘encouraged’ to use:

CR  CR  LF  Ltrs  at the end of a line. 

Was also recommended that it be done when punching tape as well. 

I do not recall if this was used when hand typing off-line Crypto tapes or not.  (5 letter groups.)  

We did it with on-line Crypto though. 

It made no difference for on-line or off-line Python operations. (Two-tape operations.)

This was in the 1959 - 1961 time frame.  

The Ltrs  character also reset machines set for ‘unshift on space’. 

For weather data, many things were different.  A whole new/different set of rules. 

Ralph- W8ROI

- - - - - - - -

Sent from my iPhone

> On Jun 21, 2019, at 5:26 AM, Steve Garrison <steve.n4tty at gmail.com> wrote:
> 
> Mattis,
> It was SOP to always send two CR and a LF at the end of a line to prevent the next character from printing on the return to the left margin. While your issue might be something not quite right, I think you'd be better served using the CR CR LF sequence at the end of each line.  It's been going on 50 years since I was a TTY maintenance jock for the USAF but muscle memory still forces my fingers to type that sequence.  Can't just type one CR.  Kind of like can't eat just one potato chip!
> 
> Steve G./N4TTY
> Sent from my iPhone
> 
>> On Jun 21, 2019, at 5:07 AM, Mattis Lind <mattislind at gmail.com> wrote:
>> 
>> 
>> 
>> Hello!
>> 
>> So I have been working with a Lorenz Lo15 teleprinter for some time. Cleaned it. Removed old sticky dirty grease and added new fresh grease and oil. Replaced three springs in the typing carriage and two brushes for the governor. Adjusted the speed of the motor. It works quite well. 
>> 
>> I designed a small circuit. Still in prototype. It is a step-up converter that creates up to 120 V DC line voltage. Then I made a small hysteresis switching current source that could generate up to 60 mA line current.
>> 
>> https://i.imgur.com/Jok5QL8.jpg?1
>> 
>> There is a small STM32 micro controller controlling desired output line voltage and line current. It also can generate some simple test patterns. 
>> 
>> The idea is to integrate RS-232, USB, and current-loop (yes for interfacing an old PDP-11) to this circuit. It should be possible to attach it to a Raspberry Pi to have more advanced services like i-Telex, news feed and a standard Bash prompt from the Raspi. The prototype only consumes 300mA 5V when driving the teleprinter so I think it would work well with a Raspberry Pi driven by a decent USB charger.
>> 
>> But there are a few problems with the Lorenz Lo15 itself. Since it is very similar to the Teletype model 15 I thought maybe the expertise here could give some hints on the problems I have.
>> 
>> 1. When printing past the rightmost end it stop spacing, it will not start spacing again after a CR. It very often requires two CR to get it back to spacing normally. 
>> 
>> I found the spacing stop lever and put some oil there but it didn't really help.
>> 
>> Here is how it looks when it is spacing normally: 
>> 
>> https://i.imgur.com/XDzz9MM.jpg
>> 
>> And here is how it looks in the stop zone and also after the first CR:
>> 
>> https://i.imgur.com/kSPE1uy.jpg
>> 
>> Any advice regarding this?
>> 
>> 2. I made a little program in the STM32 that send continous RY characters and then a CR. After the CR the next character would be printed on the way back. Is this normal and you need to insert a NUL after a CR or is my machine to slow?
>> 
>> I know that I was fiddling with the return spring mechanism and it might have lost a bit of the force. How can I adjust it to the correct CR pull force?
>> 
>> 3. If I send a BELL character it continuous to hammer the BELL whatever characters I send until it receives a CR. It will BELL on the CR but then for all the subsequent characters it will be silent (except for BELL character..). Possibly this is some sticky grease somewhere I haven't been able to clean out. But advice would be helpful!
>> 
>> /Mattis
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