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Originally Posted by Whirled One
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?
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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).