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Do TRS-80/Coco's have S-Video connectors on them?

punchy71

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Nov 16, 2011
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Do any of the Tandy TRS-80/Color Computers (model 1, 2 or 3) have S-video hook-up connectors on the back for hooking up to a TV set with S-Video connector on the back?

Thank you
 

deathshadow

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Coco 1 -- 1980
Coco 2 -- 1983
Tandy stops calling them TRS-80's -- 1984
Coco 3 -- 1986

S-Video - 1987

So... no.
 

eeguru

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Just because something is standardized, doesn't mean it didn't exist prior. And 1987 is the year the cabling standard was introduced.

S-Video is just standard definition base-band video with separate luma and chroma signals. Nearly all video dacs will produce separate luma and chroma signals then modulate and sum in the chroma component producing a base-band composite video signal before hitting the connector. JVC added the mini-DIN at the intermediate step in 1987. S-Video will be available somewhere on the trash-80 boards. You just need to review a schematic and find it. You may also have to electrically condition it depending on the video circuitry used. Separate luma and chroma will likely be fed into the RF modulator which is usually housed in a metal shroud.
 

eeguru

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No. Point taken. However the distinction still needs to be made that even though they do not have a connector, it doesn't mean you can't add one. Your reply was very absolute.
 

MikeS

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The reason I asked is because the Commodore 64 has one.
Really? The signals may be available, but do you actually know what an S-Video connector looks like?

If you're not just trolling (20 threads like this one in one month), why don't you start answering some of your questions by doing a little Googling and reading first, as one of the moderators suggested...
 
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dabone

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The coco1 has composite video available inside the unit that is fed into the rf modulator. It can be extracted with a small circuit, but the one I have tried throws the colors off. The coco2 has half the video circuit inside the modulator and has no composite available in the unit at all without adding a much more complex circuit.

coco2comp.jpg

The 3 has composite only.

As far as I know svideo is nowhere to be found because of the Motorola 6847 video chip, which was paired with the mc1372p to get the video output, and the mc1372p could be configured as rf or composite output according the the circuit.

The 3 uses a different video chip call a Gimie, it has the following.
Output to a composite video monitor or analog RGB monitor, in addition to the CoCo 1 and 2's TV output. This did much to improve the clarity of its output.

I've been trying for the last year or so to get good composite out of a coco 1 or 2, and I was finally given a coco2 that had the above circuit already installed. It works nearly as good as the output from my coco 3's.

Later,
dabone
 

eeguru

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As far as I know svideo is nowhere to be found because of the Motorola 6847 video chip, which was paired with the mc1372p to get the video output, and the mc1372p could be configured as rf or composite output according the the circuit.

Read the data sheet for the Motorola 6847. It produces a YCrCb output. It seems if you sum the chroma components you get S-Video.
 
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