Author Topic: The Scopewriter  (Read 853 times)

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Offline adritenTopic starter

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The Scopewriter
« on: May 17, 2021, 04:40:42 pm »
many years ago I saw an interesting project on an issue of Popular Elecronics and decided to build it  Essentialy it is a circuit allowing to display a sentence of max 32 charachters on the oscilloscope CRT

You enter the sentence, charachter after charachter using the relative ASCII code, then you raise a switch and voila the sentence appears on the CRT
 
A few weeks ago I found my prototype in a box and decided to see if after so many years was still working 

It worked but some charachter were no longer available
At the hearth of this circuit there is an hex 32 bit static shift register acting as the memory and for some reason one of the six channels was no longer working

After discarding the idea of buying a replacement as the IC nowadays has become quite rare and expensive I started to think how to replace it
Story short,to replace the failing chip I ended up to use FIVE ICs (2x 4053 and 3 x 4517) ; I'm sure a smarter solution does exists  Maybe some of you have have a smarter idea (?)

Attached is the original schematics (Popular Electronic Aug 74)
together with a few pic of my set-up
adri
 

Offline adritenTopic starter

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Re: The Scopewriter
« Reply #1 on: May 17, 2021, 04:44:04 pm »
apologize for the pic upside-down   :phew:
 

Offline adritenTopic starter

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Re: The Scopewriter
« Reply #2 on: May 17, 2021, 04:52:05 pm »
my set up
 

Offline jfiresto

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Re: The Scopewriter
« Reply #3 on: May 17, 2021, 07:37:46 pm »
I think I still have the LSI parts for that project. Just as I was going to use them, I got a stylish, surplus Olivetti TE300 teletype:

-John
 

Online Benta

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Re: The Scopewriter
« Reply #4 on: May 17, 2021, 07:51:09 pm »
I think I still have the LSI parts for that project. Just as I was going to use them, I got a stylish, surplus Olivetti TE300 teletype:

Cool!! Communication at 50 baud. Those were the days!   :)

 

Offline adritenTopic starter

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Re: The Scopewriter
« Reply #5 on: May 17, 2021, 08:01:44 pm »
beautiful  ^-^
1960 ?

adri

 

Offline jfiresto

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Re: The Scopewriter
« Reply #6 on: May 18, 2021, 02:47:41 pm »
I think it was made in the late 1960s. Olivetti still supported the model when we got them in 1978–9. It was pretty high tech for a mechanical, 110 baud teletype. It had a full RS-232 interface and a fair amount of electronics, perhaps to power it up and down when it received new data.

It was big change from the 60 words per minute Baudot printer I was bringing up. If I remember correctly that one had a 45.45 baud rate, 1.42 stop bits and a 100V, 60mA current loop interface which could probably work over a line running across the next couple time zones.
-John
 


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