Just the other day at a Goodwill store I stumbled on this rather interesting "modern" Zenith.
I don't see very many Digital System 3's as it is, and this is the first time I've ever seen one with a screen size smaller than 27". This must have been one darn pricey 20" color TV, that's for sure... It even has a wood cabinet, and the built-in speaker system is well above average for a TV of this size.
It's an SE2035H made in September 1988. Set appears to be in good working order, but I haven't fully checked it out yet. Interestingly, it looks like this set may have originally been a hotel TV, as it is marked with "RM 3204" in marker on a couple places on the back, but I'd think a Digital System 3 would have been a darn expensive set for hotel use (perhaps some sort of luxury suite or something..?)

Questions:
- Did Zenith make very many Digital System 3's in smaller sizes like this..? Seems kinda odd to see such a 'high-end' chassis on a 20" TV.
- The input menu includes a selection for S-Video, but the back panel doesn't have an S-Video jack. Was an S-Video connection available through a breakout box that connected to the RGB port or one of the other edge-card connectors on the back? (What are the pin-outs on those things anyway..? For that matter, Is the RGB input just TTL-level digital (like for CGA/EGA displays) or is it analog?)
- When was the Digital System 3 line introduced/discontinued..? It was introduced in 1985, wasn't it? Did they continue making them all they way until the Closed-Caption decoder requirement in 1993 (which was different from the 'world-standard' Teletext system decoder used in these sets), or did they discontinue the Digital line before then?

Questions:
- Did Zenith make very many Digital System 3's in smaller sizes like this..? Seems kinda odd to see such a 'high-end' chassis on a 20" TV.
- The input menu includes a selection for S-Video, but the back panel doesn't have an S-Video jack. Was an S-Video connection available through a breakout box that connected to the RGB port or one of the other edge-card connectors on the back? (What are the pin-outs on those things anyway..? For that matter, Is the RGB input just TTL-level digital (like for CGA/EGA displays) or is it analog?)
- When was the Digital System 3 line introduced/discontinued..? It was introduced in 1985, wasn't it? Did they continue making them all they way until the Closed-Caption decoder requirement in 1993 (which was different from the 'world-standard' Teletext system decoder used in these sets), or did they discontinue the Digital line before then?

I repaired one of those 20" sets about 10-12 years ago. It had bad soldering on the main board. Does the control panel on the door work on yours? If it does, treat it like glass because once the hinges break, the flex cable won't last long. It was really frustrating because the auto color button was one the door which made it impossible to turn off the auto color. With the auto color turned on, there was no way to turn the color down to a reasonable level.

Thanks to owning a Digital system 3 for several years, I became quite an expert on it. I've fixed quite a few over the years too.

The chip set used in them didn't have any method of accepting S-video, so they used the RGB input with an outboard NTSC decoder to simulate an S-video input. I've never seen one of these optional adapters in person, but it was mentioned in the manual.

It's an analog RGB input, but when I was playing with it I came to the conclusion that it required a much larger signal than your typical .7v p-p RGB input. Based on how dim the picture was, I would guess it needs 3-5 v p-p. I still would like to see one of these sets working with RGB from a DVD player.

I think you have the years about right. I would have guess 86-92 or 93.

They work well when they are working, but they aren't that reliable. Of course it has Zenith's famous bad soldering. There are also too many connectors, wires and plugs to have bad connections. Then there are all the socketed ICs and the leaky caps. Finally, the numerous custom signal processing ICs on the main board aren't very reliable. I saw several sets with a bad, or intermittent signal processing IC (that's almost unheard of with other TVs).

Having said that, if I saw a 20" set like that, I'd probably buy it. The set's novel design makes it interesting to me. I wouldn't be surprised if this is one of the few 80's TVs that became collectible in the distant future. It was one of Zenith's last innovative products (certainly their last innovative TV product).

Hallo! I bought a zenith digital system three I think early 90s. It's a console 27" and it's branded Heathkit model GR 2701. Since I live in Italy i never had the chance to use it. I tried in several ways to modify the digital circuitry to allow the set to turn on. It is one of the few sets it needs to "sense" the 60 hz frequency to turn on. I connected it via a power transformer stepping voltage from our 220v to your 110v but nothing happened. I had to supply a square wave 60 hz generator to the digital module to get the set on. It now switches on but picture is b/w and rolls vertically. I think this is because of the different tv system. Anyone there could tell me if the set is adaptable via "sevice modes" to other tv systemsand where is it possible to get a spare digital module?
Best regards
Marco

I repaired one of those 20" sets about 10-12 years ago. It had bad soldering on the main board. Does the control panel on the door work on yours? If it does, treat it like glass because once the hinges break, the flex cable won't last long.

Thanks for the reply, Andy! Sorry for the late response-- Real Life kinda got in the way the past several days. I think I've seen that style of control panel door on slightly earlier models, but this one doesn't have a hinged door. Actually, it's kinda cute how Zenith "hid" the control panel on this TV. There's a black trim stripe below the CRT bezel. On the left-hand side, there's the Zenith / Digital System 3 logo along with the remote sensor and a stereo indicator. The rest of it appears completely black except for a small square on the right-hand side that says "OFF-ON" in white letters. You see, about half of the "trim stripe" is actually a membrane keypad, but aside from the power switch, the 'buttons' are invisible when the TV is off. When you switch on the set (either by pressing the "OFF-ON" part of the strip, or via the remote control), a green backlight comes on behind the keypad, thus revealing the rest of the control buttons. I've seen a 27" version from about the same year that had a similar control style, but I think the few 1990's versions I've seen had regular pushbuttons instead similar to the regular System 3 and Sentry 2 sets (though I think the buttons were backlit on the Digital System 3's)


By the way, I think you're more likely to be right about the introduction year for these sets. Turns out I goofed-- I was thinking of a Zenith brochure I had that I thought was for 1985. I just found that brochure again, and it turns out it was 1987 instead. However, I can't tell from the ad copy whether or not this was actually the first year for that line. In any case, it does seem odd though that given that the Digital System 3 was Zenith's ne-plus-ultra TV line at the time, it appears that they only offered it in two models, and both are essentially identical 27" table models differing only in cabinet finish (choice of wood veneer or black), whereas the Advanced System 3 and regular System 3 sets were available in a wide variety of console- and table- models in various cabinet styles and colors.

By the way, is there any way to actually use the Teletext function of these sets these days..? Were there ever any videocassettes recorded with the Zenith-style Teletext signals in the vertical-retrace interval in the years before Closed-Captioning became popular..? (I know that the Teletext system used on these sets is different and more complex than the seldom-used "Teletext" mode that's part of our current Closed-Caption standard)

Zenith's promotional description of the Teletext feature is somewhat amusing from today's perspective. For example: "Zenith Digital gives you a subscription to the ultimate TV magazine via World System Teletext. Teletext is an electronic newspaper you read on TV. Get the latest sports, news, weather, or business information at the touch of a button." Zenith also offered an optional thermal printer as an accessory. "Prints Teletext 'pages' while you see them on the screen. Recipes, coupons, news stories, or any Teletext broadcast can be printed and retained for future use."

Well, we can do all that and more today, but it doesn't involve the TV. :) Well, not unless you're using a WebTV or similar device. :)

... the 'buttons' are invisible when the TV is off. When you switch on the set (either by pressing the "OFF-ON" part of the strip, or via the remote control), a green backlight comes on behind the keypad, thus revealing the rest of the control buttons.

By the way, is there any way to actually use the Teletext function of these sets these days..? Were there ever any videocassettes recorded with the Zenith-style Teletext signals in the vertical-retrace interval in the years before Closed-Captioning became popular..? (I know that the Teletext system used on these sets is different and more complex than the seldom-used "Teletext" mode that's part of our current Closed-Caption standard)

Zenith's promotional description of the Teletext feature is somewhat amusing from today's perspective. For example: "Zenith Digital gives you a subscription to the ultimate TV magazine via World System Teletext. Teletext is an electronic newspaper you read on TV. Get the latest sports, news, weather, or business information at the touch of a button." Zenith also offered an optional thermal printer as an accessory. "Prints Teletext 'pages' while you see them on the screen. Recipes, coupons, news stories, or any Teletext broadcast can be printed and retained for future use."

Well, we can do all that and more today, but it doesn't involve the TV. :) Well, not unless you're using a WebTV or similar device. :)

Neat, I guess the one I saw was an earlier model. That's good because your set has menus and no door to break off.

Zenith made a lot of strange (poor) decisions and I guess this was one of them. If they had been smarter, they might still be with us. My last Digital set was a 46" projector. It had a lot of nice features such as being able to route the output of your cable box to you VCR. Amazingly, it had no way to turn off the internal speakers despite having external speaker jacks and a built in Dolby surround decoder. This also made it impossible to use with an external amplifier even though it also had line level audio outputs.

The last time I saw any teletext in the US was probably 10 years ago on TBS. Even then, it was no longer being maintained (all the pages were out of date and the time wasn't even correct). You can't record teletext on video tape because the resolution isn't good enough.

Teletext was (and still is) very successful in the UK and Europe. You may laugh, but it really does all the things in that ad and it did it 10 years before the web even existed.

By the way, is there any way to actually use the Teletext function of these sets these days..? Were there ever any videocassettes recorded with the Zenith-style Teletext signals in the vertical-retrace interval in the years before Closed-Captioning became popular..? (I know that the Teletext system used on these sets is different and more complex than the seldom-used "Teletext" mode that's part of our current Closed-Caption standard)

Zenith's promotional description of the Teletext feature is somewhat amusing from today's perspective. For example: "Zenith Digital gives you a subscription to the ultimate TV magazine via World System Teletext. Teletext is an electronic newspaper you read on TV. Get the latest sports, news, weather, or business information at the touch of a button." Zenith also offered an optional thermal printer as an accessory. "Prints Teletext 'pages' while you see them on the screen. Recipes, coupons, news stories, or any Teletext broadcast can be printed and retained for future use."

Well, we can do all that and more today, but it doesn't involve the TV. :) Well, not unless you're using a WebTV or similar device. :)

I have a Zenith Sentry 2 19" TV with two teletext modes. I have never once seen anything in either mode since I've had the set except a blank black box overlaid on the picture, even on TBS. My set was made in 1995. When was TBS experimenting with teletext, and what was being carried in those experiments? I'm thinking perhaps my set was made after TBS discontinued its teletext service.

I agree with your statement about now being able to do all that teletext offered, and much more besides, with a computer and an Internet connection; one can do more yet with a fast broadband connection and an equally fast computer. Heck, with the webcasts and Netcasts available on the Web today, not to mention video podcasts offered by NBC (via msnbc.com) and possibly other networks (I think ABC also streams on-demand news via the Internet, which is why they changed the name of their nightly world news program to "World News" from "World News Tonight" a month or so ago), you don't need a TV to watch the news (or NBC's signature public affairs program Meet the Press) anymore; just call it up on your computer, any time. I often watch NBC's video podcasts when I miss the news on TV for any reason, and like it.

Teletext probably would have taken hold in this country, IMHO (at least until the Internet age got fully underway), if it had had such capability as I described above when it was introduced.

Was Zenith the only US television manufacturer to put teletext decoders in their sets, or were there other makes with this feature as well? Also, what was the purpose of two teletext modes in Zenith TVs? Were there two different teletext standards being tested in this country in the early to mid-1990s? :dunno:

My RCA CTC185 TV (and very likely other recent-model RCAs, not to mention their flat-panel LCD/plasmas and projection sets) has two closed-caption modes, CC1 and CC2. ABC's World News is closed-captioned in Spanish as well as English, with the English captioning on CC2 and the Spanish captions on CC1. Also, I think NBC captions certain of its programs (but not their Nightly News, at least not yet) in English and Spanish. The Tonight Show with Jay Leno is captioned in both languages, available on modes CC1 and CC2 on RCA TVs; it wouldn't surprise me if this is done the rest of their late-night schedule as well. The Spanish captioning is probably greatly appreciated in areas of this country with large Spanish-speaking populations, such as California, Texas and Arizona. It could be very popular here where I live as well (Lake County in northeastern Ohio), as there is a small population of Spanish-speaking folks in a town about ten miles east of me, and another in a town five miles south of here, not to mention elsewhere in the county and in the greater Cleveland area besides. This was likely why channel 61 in Cleveland went from home-shopping to Univision a couple of years ago, although I think this is just because most major US cities have one or more Univision affiliates, to accomodate the increasing numbers of Spanish-speaking immigrants in our major cities these days.

I have a Zenith Sentry 2 19" TV with two teletext modes. I have never once seen anything in either mode since I've had the set except a blank black box overlaid on the picture, even on TBS.

That's just the closed caption teletext mode which is completely different from the Digital system 3 teletext. The teletext we're talking about is interactive and capable of crude graphics.

That's just the closed caption teletext mode which is completely different from the Digital system 3 teletext. The teletext we're talking about is interactive and capable of crude graphics.

What is the difference between the closed-caption teletext in my set and the system in the Digital System 3 receivers? I read your reply and understand what you're saying, but I'm baffled :dunno: as to what the teletext decoder in my set was even there for if there was never anything to watch in either mode, even, as I said, on TBS in the '90s. There are two closed-caption modes on my set as well, the second mode (Caption 2, exactly equivalent to CC2 on my RCA set) probably being used for carrying alternate language captioning as is being done extensively by ABC for their news and prime-time shows; but the teletext decoder still is as useless as ever these days. Was there ever anything really useful being carried via teletext in this country when TBS was conducting its experiments, and did any other network or local station do anything along these lines?

The teletext service must have been close to a dud in this country, as I think Zenith stopped including the teletext decoders in their TVs before the end of the decade of the 1990s, say about 1997 or '98 if not earlier. If these TVs had been built to European TV standards the teletext decoder would have been very useful in those countries (since Europe made much more extensive use of teletext than was evident here), but it was a miserable flop in the US. Zenith should have, IMHO, left the decoders out from the beginning.

Theclosed caption text mode is just a simple text display that could be used for somthing like a news ticker. Teletext allows you to load pages of information on demand and to link to other pages. You can get things like TV listings, weather reports and airline arrivals.

Go to this page and click on Index. It will open up a window displaying exactly what you see on a teletext TV. You can then interact with it like you can on the TV by clicking on the numbers (normally you type in the number on the remote). Keep in mind that this was around in the early 80's.

http://www.ceefax.tv/

Teletext does not survive recording on VHS, but it does survive at least to some extent on S-VHS recordings. I seem to remember a teletext history site asking for any and all old S-VHS tapes they could get their hands on so they could capture the teletext data.

There were some VHS VCRs that could record teletext, but they did it by building a teletext decoder into the VCR and recording it as video. As such the interactive features were obviously lost. I think they were only really intended to be used for recording captioned programs with captions.

It could also be included on Laserdiscs for captioning, but I doubt many Laserdiscs actually used it. Some high end TVs sold here actually included CC decoding purely for displaying the captions on some prerecorder VHS and Laserdiscs (We have only ever used Teletext for captioning analog TV broadcasts).

Somewhere around here I have a PC teletext decoder card. In the pre internet days they were often used to capture stock price information. Data services were subscription based, but teletext was free.

I remember seeing an article in Radio Electronics on how to build a WST decoder. Never could find the needed board though.

I did see a NABTS demo at the CES in the 80's, and it was a CBS page (or a canned simulation) having caught my eye.

Anyone remember when Panasonic had their component "Profeel" wannabe sets equipped with RGB connector boxes on them for this express purpose.

Video on my parents C band dish sometimes contained the telltale boxes in the VBI.

Theclosed caption text mode is just a simple text display that could be used for somthing like a news ticker. Teletext allows you to load pages of information on demand and to link to other pages. You can get things like TV listings, weather reports and airline arrivals.

Go to this page and click on Index. It will open up a window displaying exactly what you see on a teletext TV. You can then interact with it like you can on the TV by clicking on the numbers (normally you type in the number on the remote). Keep in mind that this was around in the early 80's.

http://www.ceefax.tv/

Thanks, Andy. I just looked at the ceefax.tv site and saw their teletext pages. Very interesting. Had a bit of trouble getting it to work at first (server reported "object not found"), but the problem was simply that I did not have Java enabled on my computer. Once I enabled Javascript, the pages showed up just as they should.

Ceefax seems to be almost exactly equivalent to the on-screen program guides on today's RCA Guide Plus+ TVs and Motorola digital cable boxes here, except for the news services, which Guide Plus+ and digital cable do not have in their on-screen listings. I believe that teletext could have been extremely useful in this country for just that purpose; it could have provided over-the-air TV viewers with program guides, weather forecasts, etc. years before digital cable.

What kinds or types of programming were on TBS's teletext tests in the early 1980s? Were the tests conducted nationally or only in the metro Atlanta area over Turner's WTBS channel 17? If the latter, that would explain why teletext equipped TVs located anywhere else in this country did not display anything in teletext mode at any time.

Back in 1981 I was working at the old RCA Sarnoff Labs in Princeton NJ, bsck when RCA was a real company that owned itself. We were kicking around the possibility of teletext reception in the USA. The teletext "carrier" frequency was to be 2.86MHz, or more precisely 4/5 the chroma subcarrier frequency. We did field tests of teletext reception, and pretty much found that everyone with a rooftop antenna could expect to get it, but forget it with rabbit ears. One task I had to do was create a psudeo-random teletext pattern generator to feed a French made Bit Error Rate teletext meter. One big problem was that all the documentation was written in French. I eventually figured out how to do it, by visiting another lab at WCBS-TV where they had a generator, and I looked with a scope at the preambles and so on. We already had a homebrew teletext generator, so all I had to do was add an extra circuit board with parallel to serial chips (for the preamble bit pattern) and a bunch of logic to create the psudeo-random pattern. A bunch of shifts and XOR gates, and lots of glue counters to tell it when to start and stop. Today you'd program an FPGA chip.

I once suggested that a teletext equipped TV set could make a great computer monitor (this was back in the old 8 bit days of Commodore 64 computers and Atari 2600 game machines, that used TV sets on channel 3 and you had fuzzy characters on the screen). Just have the computer "fake" a TV channel with teletext signals encoded on it. I don't think anyone ever actually did that.