TV Typewriter II

[utuberangerbob]

A few pictures of my beautiful SWTPC TV Typewriter II. It's been in storage for maybe 30yrs and has lost a few keys, probably from having heavy things hastily stacked on top of it. I will be reviving her in the next month or so. The AC power zip cord has been cut off and will be replaced with a fused IEC socket in the rear. Still trying to find a better position for the power supply, but that bulky transformer doesn't leave many options. Should I go switcher? The BNC video connector will also be moved to rear. Right now, she's a pain to open because the wiring between chassis connections and boards is tight. Will make new wire harnesses with connectors to ease in future disassembly's.

The big problem...keys and key caps. I've struck out with internet searches, and consensus is they are unobtanium. I may try 3d printing some new inner body parts where the stems are broken, and finding any caps that will fit. But I'm not opposed to replacing them all with new key switches and caps.

 

[utuberangerbob]

Does anyone know why SWTPC TVT II boards were labeled DLS? I thought maybe it was for something like 'Don Lancaster Systems' but could not determine if there ever was such a company.

 

[Al Kossow]

If you look at the original articles, the follow-ons weren't designed by Don

Feb 1975 Radio Electronics

Feb 1975 Radio Electronics

The company that made them was in Oklahoma City. I'm digging for their name
Somewhere I have a prototype blank board that someone who used to live there gave to me

 

[utuberangerbob]

Yes, I knew that, but couldn't think of any other reason for the DLS. I read about an engineer at SWTPC thinking, 'hey, we could make this better'. But maybe they still had to license it from Don? Another possibility is that it was the name of the board fab shop, but why wouldn't SWTPC put their name on it as well?

 

[Al Kossow]

pics of the board http://bitsavers.org/pdf/southwestTechnicalProducts/CT-64 main_top and main_bot
has the initials dov/jpv on it

 

[Al Kossow]

the articles were written by Ed Colle

Radio Electronics February 1975

 

[utuberangerbob]

More mystery. I can't find the article I read about the development of the TVT II, but I seem to remember that the designer was Ed Colle, which doesn't line up with those 'initials' either.

 

[Al Kossow]

ah.. I also see the confusion. what you have is the CT-1024

 

[Al Kossow]

from the tvt wikipedia article
Daniel Meyer of SWTPC enlisted Ed Colle, an engineer who had worked at Datapoint on terminal design, to design the new TV Typewriter. The SWTPC CT-1024 Terminal displayed 32 characters by 16 lines without scrolling. It used common TTL parts and 2102 static RAMs. The boards were laid out with very loose part spacing and wide traces to make it easy to assemble. A complete set of option boards was offered including a serial interface. The keyboard was based on Don Lancaster’s design. The rest of the terminal was done by Ed Colle.


sigh... I was confusing SWTP with PAIA. there was an Oklahoma City hobby computer group, and a member gave me this along with some PAIA boards.

 

[utuberangerbob]

Well, son of a gun, looks like it is a CT-1024. The picture of the TVT II in RE looks almost exactly like mine, except you can just make out only two rows of connectors at the back of the motherboard in the picture. My motherboard has three rows with four boards.

Edit: Still a TVT II? "In 1975 SWTPC introduced the TV Typewriter II (CT-1024)."

 

[syzygy]

From the CT-1024 'manual'

For those readers interested in finding out more about the circuitry in the
unit, it was printed as a construction article series starting in the February 1975
issue of Radio-Electronics Magazine (TV Typewriter II page 27). If you do not have
a copy of this magazine, you can probably find one in your local library. The
CT-1024 (TV Typewriter II) is totally different from the TV Typewriter I printed in
an earlier issue of Radio-Electronics Magazine. The two were designed by different
individuals and their option boards are not interchangeable with one another. We
are no longer supplying any of the parts for this older TV Typewriter I.

The collected RE articles are here and you can see the D.L.S on the artwork for the boards on (almost) all of them.

Also from here,

This brochure was written in late 1975. SWTPC generally did not put dates on the documents but this was an exception. It has the notation CT-01 Oct. 1975, however later versions of the brochure that included a newer keyboard (KB-5) also had the Oct. 1975 date. Getting the date right was not a priority.

Cool stuff, it was a pleasure to be around while all this was going on, even if I was only an (mostly) observer.

Yeah, seems like the D.L.S was unrelated to Don Lancaster.