S-Video Checkerboarding and Jailbars - why it happens and how to fix it

[@alleycatjack4562]

Awesome video. Great example of analog video cross talk and how to sniff out the issues and improve.

[@carraror]

The most thorough explanation on the subject: thank you!

[@geofftottenperthcoys9944]

You look like you escaped from the 70's at the start of the vid!

[@JacquesMartini]

It's all part of the role! RETRO!!!!

[@JacquesMartini]

What the heck? Get some pieces of RG174 and be good! You try to solve em EMI issue with bell wire! GENIUS!

[@fortmax8370]

I had a 3rd party SNES/N64/GCN cable with both composite and S-Video cables that had the same checkerboarding on the S-Video, but for a different reason: they hooked the S-video's luma to the composite pin because it'd save them a connector.

[@TheRetroChannel]

Ugh yeah so many dodgy cables out there and using composite as luma is a recipe for maximum checkerboarding

[@JacquesMartini]

What an irony! Using a S-video signal for better isolation of luma and chroma information messes up the result due to crosstalk and cheap design. Well done! Sounds EXACLTY like commodore engineering style!

[@TheRetroChannel]

They did learn their lesson once they got to the shortboard C64. There's ground traces running in between luma and chroma on those boards. Unfortunately the crappy RF modulator and VIC-II introduce crosstalk and makes their efforts on the PCB practically useless

[@DaveDoc1984]

Great video as always mate. The information is very useful and its something I have wanted to tackle with my C64 for a while. I also have a Japanese MegaDrive that exhibits Jailbars when used with an RGB Scart cable. The cable itself is decent one from a reputable Retro Console Accessories seller.

[@TheRetroChannel]

I hear some megadrives are prone to it. Look into the triple bypass mod

[@josephlunderville3195]

Have you tried using a ground wire just twisted around the luma bypass wire instead of going all the way to a coax wire? It would be a lot simpler/cheaper and I've had good luck with it for longer digital runs.

[@rimmersbryggeri]

Giana sisters. You have some digital inteference from mister Benchley on the digital video, is there an RF mod for that? 🤣

[@vk3hau]

23:42 that’s a Red Back Spider egg sack.

[@herbertwongsanimations6266]

When I have my SNES connected via s-video to my 68cm crt TV it's fine. When I have it connected through a s-video switch box it gets checker board. It's like looking through a fly screen.

[@danieltornqvist6062]

Couldn't you isolate the wire by ising sole metal or aluminium tape under where the cable go? Might not be as good as a isolated cable. But I'd be curious to aee if it made any difference. Nive fix as always!

[@TheRetroChannel]

Could make a difference, but then you've gotta be careful of exposed vias

[@josephlunderville3195]

Remember to ground the metal tape at both ends, also!

[@JacquesMartini]

Yeah, a mV measurement with three digits after the decimal separator! Thats real engineering! 😂

[@SeanChYT]

On my C0pperdragon analog-only systems, I have jailbars on composite, but not with S-Video. I really want to get rid of it on Composite too as it is pretty bad (worse than with stock RF mod). Have tried one of those boards you put inbetween the VIC-II and the socket with pots to turn, but I couldn't get it to improve the picture.

[@TheRetroChannel]

Isolating the luma from the VIC-II to the RF mod may help. Same as I did in this video, cut the trace at both ends and run a shielded wire. If you do this, I'd experiment with connecting one end of the shield to ground, and both ends. From what I found it made no difference so I just connected both ends, but it may make a difference for you. And yeah, lumafix is useless IMHO, it doesn't address the root cause of the issue

[@SeanChYT]

@@TheRetroChannel Thanks for the advice. I will give it a go.

[@gljames24]

Those are Magenta and Cyan literally, not purple and blue. Purple is close enough, but cyan is as far away from blue as yellow is to red.

[@SireSquish]

What would happen if you tied pin 13 to ground with a 1k resistor?

[@JacquesMartini]

You call this a tip? THIS is a soldering iron tip! 😂

[@wilburt6131]

You're only supposed to ground one end of a shielded wire

[@TheRetroChannel]

Yeah, I've read conflicting reports about this. And I did experiment with only connecting one end and both ends and found it made no difference. I understand it could create a ground loop, but we're talking about nearby grounds anyway and not two separate pieces of equipment

[@josephlunderville3195]

That's only true if the other end goes to an isolated appliance -- typically within a board where there should be a shared ground running round anyway you'd ground both ends (and if there are components on the board at both ends of the link I'm pretty sure you MUST ground both ends or you risk making an antenna loop)

[@shangrilai1990]

🍪

[@TheRetroChannel]

Oof 🥈

[@shangrilai1990]

@@TheRetroChannel 🙏Forgive me oh Retro one