Hi. I know there is a plethora of information regarding the C64 and s-video onliine but I've come to my wits end.

A few weeks back I set about building my own S-Video cable for my C64 (early 90's model). I duly built the cable but had horrible problems when sound played (the picture would jump around).

After fiddling around I improved the cable but I still got slight interference on the picture when loud sounds played so I gave up and ordered a cable from Ebay (lifes just too short).

It turned up today but gives an awful picture on my television. Looks like a hell of alot of choma noise. Added a resister (it was missing the one I had on my own lead) but that reduced the saturation but not the noise.

Undeterred I plugged the lead into my VCR. This gave a stable picture but quite bright with pixel patterning all over the screen. Looks good put the patterning is really offputting.

So I then tried a resister on the luma line, but that made no difference.

So I'm confused really. At one stage I had an almost working home made lead but the "professional" lead gives a noisy picture. It looks like the kind of stippling effect you get on Speccy games. Thing is its doing it on solid colours!

One weird thing I did notice is that you could disconnect the chroma line and still have a noisy colour picture. It's almost as if chroma information is bleeding through from somewhere.

Anyone have any idea? Having had a taste of what the C64 could look like (with my own lead) I'm keen to get the image looking as good as possible.

THanks.

Have you seen this thread?

Are you sure your C64 is OK?

Quickest way to find out is to try a different C64... and different TV.


Perhaps there's a power problem, when the SID draws power the VIC-II is affected. Could be a defective SID, perhaps poor connection due to oxidation on IC or socket... or the TV itself that has some defect.

You should also use the correct type of cable, 75 ohm for chroma and luma and 50 ohm for sound. Poor shielding can also result in interference being picked up.

So what kind of TV do you have?
Have you tried "just" composite video and checked if it's OK?

Composite is fine.

The TV is a Samsung which is usually fairly tolerant of most old systems but I don't run s-video off anything else. I usually plump for RGB.

I have a whole collection and the only thing it ever disliked was my Amiga which was fixed with a resister.

Clearly the problem is one of leakage but I am unsure how my homemade lead inadvertently cured this! I had a solid clear s-video signal but interference when sound played. Clearly I must have miswired it but somehow it convinced the TV it had s-video!

If I run the C64 through a Panasonic VCR first, I do get a solid picture. But I do get a strange pixel patterning which you can just about see on this photo:



I'm wondering if this is normal? Running through the VCR isn't the end of the world but the pattern is quite distracting!

The VCR is a fairly sophisticated Panasonic unit which is extremely tolerant of most video signals. I'm wondering if the pattern displayed is a side effect of the banding you see on the C64 combined with confusion over the 64's lack of interlacing?

Any thoughts? I do have another 64 somewhere which I can test at somepoint.

That pattern can usually be removed (has successfully been removed) by increasing the resistance on the chroma signal line.

In the end it's the VIC-II chip that isn't super-duper quality, it can differ a lot between different chips. It leaks chroma signal into the luma for example, nut much that can be easily done about it.

Perhaps you should get a Chameleon instead and enjoy emulator perfect picture...

Can't really go for a Chameleon as the whole point of getting the picture up to scratch is for the eventual arrival of a 1541 Ultimate.

I did play with adding more resistance to the chroma line, but it just reduced the colour without impacting the dots.

See if you can swap the VIC-II chip, is it in a socket?

Are you in PAL or NTSC land?

There are some PAL ones available here:
http://www.oldsoftware.com/CBMchips.html


Even then, some TV:s can't handle the C64, it's as simple as that.
My C64C looks great with S-video on my old 32" WS Panasonic TV, get the same pattern effect if I hook it to the 19" "WS" LCD TV (it's more like 14.4:9 than 16:9).

Well, I have my s-vid lead plugged into the back of my Magnavox DVD Recorder, which then connects to my oooold Hitachi TV via the F-connector, and the video is clear enough, but rolls like a bugger.

Any ideas Oge or others?

Curt

Your Hitachi TV should be capable of S-Video through SCART (if PAL). Have you tested that?

Cheers,
Oge
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I've just been able to display S-Video onto a TV (Triniton CRT) which refused to display C64 S-Video at all and thanks to a modification different than the 330 Ohm one.

The quality is not optimal, but it is an improvement compared to when TV only showed red shadows of the C64 startup picture. Let's see if this thing can be improved. Maybe there is place for other Chroma modifications.


Cheers,
Oge
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How much of a market do you guys think there is for a simple piggy-back solution to give you high quality S-Video?

This would be a board where you would remove the VIC-II chip and install it on to a low profile board that plugs into the original VIC-II socket, using machined tooled pins. There would be a simple 4 wire cable connection for Luma/Chroma/GND/GND. I could even make up adapter cables where you could attached a S-Video plug into the C64's case (after drilling a hole for it and perhaps a couple of holes to hold the connector in place).

You really need more than just a few simple transistors to get high quality video.

Id be be interested in just a bare printed pcb ready to have components etc fitted (so save on costs), however not sure if it would cure the problem, in the link above i made a dirty opamp for it - this was ok, but still not great on all tv's. Unless of cource the circuit you suggest is a better design? - that would be very handy

The circuit I have used in the past converts Luma/Chroma to either S-Video compatible or RGB component outputs. It's a video processor.

The part is a video processor w/RGB weighting. This will take luma/chroma and provide a balanced R/G/B or composite+sync and color (s-video) output.

A big side note to all of this is there are sellers out there that have cables made with the resisterin it.
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All I know is that I want to have some way to get my Acer 22" LCD to give a clear picture for my Commodore 64C's output.

That cussin' blue/tinted bar that always ends up on the very top of the 64C picture when I feed the S-video from it to this s-vid to VGA adapter ...

http://www.ebay.ca/itm/TV-RCA-...2c606df20e

... just plain drives me mad.

Curt

What do you know. I have that same product and when I feed my 40 column mode C=128DCR and my Commodore 64 video through it, it looks like total shit!

I would say your best bet is to get this cable. I bought mine from protovision but it was made by the maker(s) of the site I just gave you. It works fine on my LCD at home. I actually used it on some of the videos I did and I have one for my Commodore 64 Arcade Cabinet. The only thing that I was sorry to get was a Computer monitor with S-Video in. Basically, it doesn't have good up-scaling in it.
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Now, if I were only better with German!

True true mistermsk ... my only issue with all these cables is that I have purchased another 2 (I think it was 2) of those same kind of S-video cables from another guy in the UK who claimed that they were high quality, blah blah ... but still the problem exists with getting the VGA signal clear, y'know?

Is it all in the cable build, guys, or are the adapters the real issues?

If so, how does an everyday user (like me, LOL) actually know which ones to go with? Just dunno what to make of it all.

Curt D.