Electronic Systems 106 kit TV Typewriter

This is an Electronic Systems Number 106 TV Typewriter board in operation.

I picked up two of these at an electronic supply and surplus store sometime in the early 1980's for around $20 as I recall. I recently "found" them on a top shelf in my garage and decided to see if I could make them work again. I had never actually tried them after I bought them because I had no data or a schematic for them.

They were in horrible condition, cut traces, missing chips, even one chip with a pin folded under. I had to replace two sockets on this one as they were such cheap quality sockets that the pins had broken. This one is still slightly intermittent so I will probably have to clean every chip socket and touch up more solder joints. I already have over 30 hours into this one. The 9 key thing on the right is something I made for the cursor up, down, right, left, page up, page down, home, EOS, and EOL keys as the keyboard is a basic as it gets.

As a matter of fact, the keyboard is the reason I have these two TV Typewriter boards. I had wire wrapped the Ed Colle TVT version 2 on perfboard and needed an ASCII keyboard. I went to Ancrona Electronics, a local parts and surplus store that was at 4518 E Broadway in Tucson at the time and bought their George Risk Industries 756K demo keyboard and case.

It was a kit they had assembled but was missing the letter "A" keycap and the case was really for a different model keyboard so the owner let me have it at a substantial discount. You may notice a sideways "M" key for the "A" key.

While browsing their surplus shelves, I found the two assembled TV Typewriter boards.

A shot of the output on my vintage 9 inch RCA B&W monitor. This and the Sanyo model were commonly used for these as well as early Apple 1 & 2 computers. I do have a Sanyo monitor but the RCA has better brightness. We used these for security camera monitors where I used to work and when they upgraded to a new color security system, I snagged a couple of the monitors before they got tossed out.

A close up here of the actual pcb. That thing you see in the 2513 character generator socket is an adaptor to use a AT28C16 EEPROM with the CG data programmed into it. One of the boards was missing it's 2513 chip and I was using my adaptor and AT28C16 in case I blew something up. In case you haven't looked, genuine 2513's are going at stratospheric prices these days.

Most of the chips on both boards have date codes in the 74XX to 78XX range so I am guessing this thing was assembled in early '78.

The ribbon cable draped over the board is from the GRI keyboard. The twisted pairs is from the 9 key keypad I made. The red/black/yellow/orange wires run off to an old Control Data power supply that I have which is capable of +5V, -5V, +12V, -12V, a 10 volt AC supply and a +20V supply. An RCA cable connects it the video monitor.

One thing you might notice about the board, Both long edges have about an eighth of an inch shaved off. When I got these boards, they were mounted in a large aluminum chassis and they had been trimmed so both fit side by side and completely filled the chassis.

What did I do with the wire wrap version of the Ed Colle TV Typewiter? It's stored in a closet in my shop. It was part of a CCTV TV educational channel at the hospital where I worked. I also built the Don Lancaster "Put the Time on you TV" project as wire wrap and it occupies three cards in a Vector cage. One card is the sync generator and video mixer, another is the actual time display card, and the third is a clock. The sync generator circuit uses a MM5321 sync generator chip that made industry standard NTSC sync. The time and TV Typewriter boards both synced off this circuit to generate a standard TV display with the time at the top and text scrolling up from below. It had information about patient services and phone numbers of various departments.

The time was derived from dividing the 60Hz power line into seconds and counting minutes and hours, etc.

A link to the Youtube video showing that part of the project: CCTV_Control

As part of this TV channel, we had two commercial VHS tape players that had wired remote controls. I used another wire wrapped logic card to start the machines at specific times using the clock card. Then I had DTMF "touchtone" sequences recorded on one channel of audio which was detected by another card with phase locked loop tone decoders and switched the machines on and off the air and stopped them. When they weren't running, the time and TVT was displayed. For audio, I initiallaly used an FM tuner tuned to a soft music channel. When ASCAP, BMI, and SESAC got testy about using music for commercial purposes, we contracted with a local "Reading books for the blind" service to use their audio.

This ran for about 8 years until we got cable TV for the patients and I removed it and kept everything except the VHS players. I will take some photos of them in action and post them eventually.

Ironically, everthing this massive collection of TTL logic could do is now possible with a $10 Raspberry Pi running Linux. I have built a video player with a Pi which with a little additional Python could do all this!

For more information about this particular TV Typewriter, please visit the deramp.com webpage. I am deeply indebted and grateful, for without his webpages, I could not have gotten this thing working.

Last Updated - 08/22/2021