Homebrew PCBs

Tom,

Your description of the modified TV for use as a monitor triggered my 
memory.  Although I didn't build the TVT, I used the  handbook to modify 
a small screen TV for use as a monitor.  Yes, it had a hot chassis.  I 
used it with a computer board that I read about in Radio Electronics. 
The CPU was the Signetics 2650. I bought the board from Central Data and 
stuffed it myself. It came with the ROM listings in a poorly printed 
book.  I manually programmed a 4K X 8 PROM. Much to my amazement, got 
through it with no errors and the computer worked.  I remember one quirk 
of the monitor.  Alternating lines of text angled to the left and 
right.  I wanted to troubleshoot the system, expecting that there were 
some sync issues, but with the monitor having a hot chassis, and the 
scope having a grounded chassis, I didn't try.  The board came with a 
version of BASIC on an audio cassette. That was loaded from a modified 
audio tape player. Soon enough, the system was replaced by a Commodore 
64, and the 2650 board relegated to long term storage bin in the sky.

(Another) Harvey

On 3/19/2016 10:12 AM, 'Tom Crawford' ah983@... [Homebrew_PCBs] 
wrote:
>
> This TV Typewriter thread has triggered some interesting thoughts, 
> that might be of interest.  I recall building one of these, so took a 
> look through my project files (I keep stuff way too long...)
> Found a picture of what I built, dated May, 1980. The photo note says 
> it was a CT-1024, actually, not an original TVT.  Photo includes a 
> large aluminum box I hand-built from flat stock to hold all the 
> electronics, power supplies and connectors, and a separate Keyboard, 
> with a cable connection to the box.  I made all the PCBs myself from 
> the plans, and soldered a wire into every via of the set of 2-sided 
> boards.
> Behind is a modified BW TV to use as a CRT (prob. hot chassis, as I 
> remember!  I hope I had a polarized plug wired correctly to it!).  
> Sitting next to it on the table is a home-made \u201cPennywhistle\u201d 300 baud 
> acoustic coupled modem.  The phone handset cradles were made from 
> cut-down soup cans, lined with weather-stripping foam.
> After looking at the photo, I realized I had seen that big aluminum 
> box recently, so after some poking around my workshop, I found the 
> entire CT-1024, and it\u2019s keyboard!  (The modified TV and Pennywhistle 
> I knew were gone, replaced quickly with a safer and clearer surplus 
> CCTV monitor, and a faster 1200 baud direct connected modem...)  I\u2019m 
> tempted to plug it in, and see what happens, but I don\u2019t really need 
> another project.  Maybe someone else wants to try...?  I also took 
> some new pictures, including the insides and the circuit boards, I 
> will see what\u2019s involved in posting them, if anyone is interested.  
> Sorry, don\u2019t know what type of PCB material I would have used at the 
> time [g].
> This device replaced a modified IBM Selectric (From a \u201cComputyper\u201d 
> device, as I recall), which never did work very well.  Used for some 
> online BB access locally, and with my first microcomputer, a 
> \u201cTek-1802\u201d (RCA 1802 cpu, ram, hex keypad, 7 segment displays...)
> I moved on fairly quickly to a hand-built \u201cBig Board\u201d (Z80, 64K RAM, 
> 80x24 display generator, 2x 8inch floppy drives (cost a fortune, even 
> surplus!), running CP/M.  Used this for \u201cserious\u201d software development 
> in C.  Was followed by a hand-built clone Apple II with floppies, then 
> my first purchased IBM PC....
> fyi,
> Tom Crawford
> *From:* mailto:Homebrew_PCBs@yahoogroups.com
> *Sent:* Friday, March 18, 2016 5:01 PM
> *To:* Homebrew_PCBs@yahoogroups.com 
> <mailto:Homebrew_PCBs@yahoogroups.com>
> *Subject:* Re: [Homebrew_PCBs] TV Typewriter: Custom G10 copper clad
>
> I built one to replace my clunk model 45 Teletype, eventually I 
> replaced it with a Televideo 950.
>
> On 3/18/2016 3:37 PM, 'Brad' unclefalter@... [Homebrew_PCBs] wrote:
>>
>> Also on the original front \u2013 I don\u2019t think anyone harboring an 
>> original TVT project would be willing to give it up for less than 
>> lots of money, given how rare and important historically they are. So 
>> that\u2019s why I\u2019m not holding my breath there.
>>
>> *From:*Homebrew_PCBs@yahoogroups.com 
>> [mailto:Homebrew_PCBs@yahoogroups.com]
>> *Sent:* Friday, March 18, 2016 10:35 AM
>> *To:* Homebrew PCBs mailto:Homebrew_PCBs@yahoogroups.com
>> *Subject:* Re: [Homebrew_PCBs] TV Typewriter: Custom G10 copper clad
>>
>> Yeah
>>
>> And besides, there are scant few folks around in hobby electronics 
>> nowadays that have ever actually
>>
>> laid eyes on a finished (or unfinished) Lancaster TV Typewriter. It 
>> is totally obsolete by todays standards and state
>>
>> of the art.
>>
>> And, as Lancaster envisioned, the thing was to be enclosed in a kind 
>> of wooden desk-top enclosure, so
>>
>> nobody sees the circuit boards anyway.
>>
>> Too bad that a search can't somehow be made on the internet, 
>> inquiring if there is some
>>
>> "old-timer" (like me) that has a Lancaster TV Typewriter in a dusty 
>> pile of forgotten projects,
>>
>> and that way, you could get the "real" item and bring it back online.
>>
>> These are just suggestions.........now, don't everbody jump on me 
>> with snide remarks.
>>
>> Regards.
>>
>> Roland F. Harriston, P.D.
>>
>> ***************************
>>
>> ------------------------------------------------------------------------
>>
>> *From: *"Stefan Trethan stefan_trethan@... [Homebrew_PCBs]" 
>> mailto:Homebrew_PCBs@yahoogroups.com
>>
>> Snip:
>>
>> Most people are going to look at you as if you are crazy for wanting 
>> a specific colour and weave of material. That is because you are 
>> crazy of course, and nothing to worry about.
>>
>> It will not help your quest at all, but consider buying double sided 
>> laminate (with copper on both sides). I found it much easier to 
>> obtain and just etch one side away completely for single sided 
>> boards. Of course it makes impossible to see the inside.
>>
>> Also mind that in any case the copper on the other side will severely 
>> change the colour you see, even if the seller provides a photo of the 
>> board side. The copper layer is actually a dark red underneath, 
>> completely different colour from the shiny top surface.
>>
>> ST
>>
>> ------------------------------------------------------------------------
>> Posted by: "Brad" mailto:unclefalter@...
>> ------------------------------------------------------------------------
>>
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>
>
> -- 
> Cecil - k5nwa
> http://thepartsplace.k5nwa.com/
>