S-Video conversion possible as plug-and-play solution?

Modding and Technical Issues

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Oge_user
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Re: S-Video conversion possible as plug-and-play solution?

Post by Oge_user »

You could try amplifying the Chroma and then 0,1uF/1uF bipolar capacitor plus 470/1000 Ohm resistor between VIC and TV in order to protect the VIC itself. And a 75 Ohm (Chroma to GND) resistor as a final touch.

Connecting chroma straight on TV was discouraged several times while testing with the C64 S-Video modifications for the purpose of protecting the VIC-II.

In case of straight connections of Chroma to TV the quality will strongly vary depending solely (IMO) on the quality of the inner circuits of the TV. On CRTs you can still get a good result with VIC>TV direct connection.


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RobertBe
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Re: S-Video conversion possible as plug-and-play solution?

Post by RobertBe »

I wrote:Using Eslapion's above solution as a starting point, Ray Carlsen just modded my main NTSC VIC-20 for s-video!
I was so pleased with the VIC-20CR that Ray modded for s-video that I'm having him mod my early (PET-key-style) NTSC VIC-20 for s-video.

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Re: S-Video conversion possible as plug-and-play solution?

Post by eslapion »

RobertBe wrote:I was so pleased with the VIC-20CR that Ray modded for s-video that I'm having him mod my early (PET-key-style) NTSC VIC-20 for s-video.
IMHO, the S-Video mod on older VICs brings the best results. Early VICs have better quality video amplifiers which produce less video noise.
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RobertBe
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Re: S-Video conversion possible as plug-and-play solution?

Post by RobertBe »

eslapion wrote:IMHO, the S-Video mod on older VICs brings the best results
Heh, I probably won't be able to tell the difference in quality from a s-video modded older VIC and a s-video modded VIC CR.
Have a nice trip in Canada!
Thanks! This is my fourth time to Victoria. Now it's time to get out of the hotel room and explore the shops, restaurants, and Chinatown. (Not necessarily in that order...) :)

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Re: S-Video conversion possible as plug-and-play solution?

Post by Boray »

eslapion wrote: IMHO, the S-Video mod on older VICs brings the best results.
I guess you ment later vics? Or do you mean an early model modded will bring the very best?
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Re: S-Video conversion possible as plug-and-play solution?

Post by eslapion »

Boray wrote:I guess you ment later vics? Or do you mean an early model modded will bring the very best?
I mean...
Early VICs have better quality video amplifiers which produce less video noise.
Which means the s-video mod will make biggest impact on late models. Biggest impact = best result.
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RobertBe
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Re: S-Video conversion possible as plug-and-play solution?

Post by RobertBe »

eslapion wrote:
RobertBe wrote:Early VICs have better quality video amplifiers which produce less video noise.
Ray wrote to me last night that the VIC I turned in for repairs has a board he's never seen before - one where the major chips are fully socketed. Since that is the case, it will be easy to add JiffyDOS and a R65C02 to it.

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Re: S-Video conversion possible as plug-and-play solution?

Post by mrr19121970 »

What board & REV number is it?
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Re: S-Video conversion possible as plug-and-play solution?

Post by RobertBe »

Ray says it's a "very early E version."

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Re: S-Video conversion possible as plug-and-play solution?

Post by Boray »

eslapion wrote: I mean...
Early VICs have better quality video amplifiers which produce less video noise.
Which means the s-video mod will make biggest impact on late models. Biggest impact = best result.
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Re: S-Video conversion possible as plug-and-play solution?

Post by mrr19121970 »

I second this.
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Re: S-Video conversion possible as plug-and-play solution?

Post by eslapion »

@mrr19121970 & Boray

Unfortunately that's not what I saw.

The S-Video mod improves the image resolution significantly but the VIC-20cr has a lot of unfiltered noise in its video signal mostly caused by the video amplifier's poor choice of components.

Since the S-Video mod still uses the onboard video amplifier for the luma+sync signal, the noise stays there. In the end, the older VIC-20s provide a better image quality without or without the S-Video mod. This mod providing an equivalent improvement on both machines, the 2-Prong PSU VIC-20s with S-Video mod are the ones giving the best image quality overall.
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Re: S-Video conversion possible as plug-and-play solution?

Post by Boray »

eslapion wrote:This mod providing an equivalent improvement on both machines,
Well, most CR machines suffer from severe graphics graininess which this mod cures.
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Re: S-Video conversion possible as plug-and-play solution?

Post by Boray »

Boray wrote:
eslapion wrote:This mod providing an equivalent improvement on both machines,
Well, most CR machines suffer from severe graphics graininess which this mod cures.
Is this only a PAL land problem???
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Re: S-Video conversion possible as plug-and-play solution?

Post by eslapion »

Boray wrote:Is this only a PAL land problem???
It's possible. I have a PAL VIC-20cr which doesn't have the S-Video mod and I noticed the color encoding does cause a serious polka dot pattern.

It seems the color encoding on PAL VICs is not phase alternating from one video jiffy to the next as it is on NTSC VICs.

However, this effect is caused by the way the video chip works, not by the video amplifier, so it should be the same on all PAL VIC-20s.
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