Odd image problem in 2D fighters using SCART

[genesisknight]

So after putting up with S-video shittiness on a plasma screen, I finally decided to leave all that crap behind me and opt for the SCART route. Since I"m in the US this lead to the following setup:

US NTSC Saturn -> RGB SCART cable from Rob Webb -> converter -> Plasma.

Here's the converter: cgi.ebay.com/SEGA-SCART-RGB-YPbPr-YUV-Component-Video-Converter-/220698773448?pt=LH_DefaultDomain_0&hash=item3362ac07c8

Needless to say this looks incredibly sharp and generally fantastic since Panasonic Plasmas handle 240p content very well.

But here's the deal - you know how in most fighting games (Street Fighter Zero 3, Vampire Savior, Waku Waku 7, Samurai Shodown IV) the screen 'shakes' during throws to indicate heavy damage? Well whenever this happens, the image on my screen 'jumps' - hard to describe, but it's like the screen jumps off the top or bottom end of the screen and comes back around in the blink of an eye. Very jarring.

Could this be due to my cable or converter? Anyone ever experienced this?

[Yart]

I have that same adapter. That's the exact same setup I use.

Yea I get that too. Still haven't figured out the problem. I find fooling with the power option on my adapter (I had to use a universal adapter since the product is from Europe) and fooling with the cables (both power and video) fix it if you set it right.

That, and some TVs just have trouble because from what I understand the Saturn in the US sends out a different voltage for the sync or something like that. Someone else will be able to tell you about that detail.

[genesisknight]

Huh, mine came with an AC plug that works here in the USA, but I know the type of universal plug you're talking about with the voltage switch. Perhaps I should look into using one of those. Glad to know it's not just me though.

Do you also experience somewhat of a greenish tint or desaturated reds?

[Yart]

I did, but that's the result of poor connectors on the device itself.

Fool with the cables, like I said. The jumpy picture is also probably a product of the green cable not being in right since that's where the sync goes through.

For months I thought my cable was shorting out but turns out the actual device itself is the culprit. You have to do a lot of playing with it unfortunately. :/

[zyrobs]

Your converter can't handle the video sync line. Try adding a resistor in there somewhere.

[genesisknight]

I really doubt I have enough electronics skill to add a resistor, I don't think, but I could try. Surely not just any resistor?

But at any rate it sounds like it's not the cable, it's the converter. (Although Yart you say the green cable is not in the right place which seems to contradict this?) That's good - at the worst I could just try a different converter.

[Yart]

No that's no contradiction. Play with the green cable and that flicker might go away.

[genesisknight]

I feel really dense; but do you mean the green wire in the SCART cable or the receiving port in the converter? And by play with it, do you mean adjust it, add a resistor, etc? Thanks.

[buckoa51]

You could also try using composite sync rather than composite video for sync, this helped a lot in my setup.

[Yart]

Yea buckoa's advice will help.

I mean green wire on the three prong side of the device. You know... the component video side that goes to the TV.

Just fiddle around with it, like you know how sometimes you have to play with the position of an RF cable to get a good picture? Same deal.

Do that with the other two cables and your colours should clear up too.

[genesisknight]

Oh, component plug, got you. Well, can't hurt to try. I'll report back in a bit. I don't understand buckoa's advice either - are those options on the TV, or a hardware modding thing?

[buckoa51]

Usually a hardware mod, what you need to do is swap pin 8 on the saturn end over to pin 1, so you are getting a pure sync signal rather than using composite video for sync (http://www.videogameperfection.com/scart.php#synctypes). Often easier said than done considering you can't get into the 10 pin end on most SCART cables, but depends on your SCART cable.

This works a lot better on some systems usually video-processors, though for some equipment you might need to put a resistor on too.

[genesisknight]

Found this: is this the mod you guys are talking about?

www.sega-16.com/forum/showthread.php?13966-Mod-How-to-make-an-NTCS-Saturn-work-with-an-EU-scart-cable

[zyrobs]

Jul 12, 2011 23:19:51 GMT genesisknight said:

Found this: is this the mod you guys are talking about?

www.sega-16.com/forum/showthread.php?13966-Mod-How-to-make-an-NTCS-Saturn-work-with-an-EU-scart-cable

No, that mod remove composite sync from NTSC models and replaces it with a +9v line so any idiotically wired Scart cables will also work on NTSC models. (PAL Saturns have c-sync replaced with +9v on the av out, and many scart cables use that for the voltage required to activate rgb mode)

The mod we are talking about is replacing the composite video line with pure composite sync, so you get no crosstalk from the composite signal (which causes the ghost rollover that is a common problem in scart rgb cables for saturn). The process for that would be removing the diode labeled EM8 (look near the av out, it's one of the lined up small blue/black boxes), and then connecting the points labeled TP4 to TP5 (on the underside).


Edit: I just read that you are using a panasonic plasma... the problem is definitely in your converter then, since I use a very similar setup with no sync problems. (pal saturn -> rgb scart from rob webb -> panasonic tx-p42g10e)
And if the screen shakes during high contrast jumps, then adding a resistor to the composite video line on the scart plug may help. Just open it up and solder a resistor to pin, I think it was 19 but you should look it up just in case. You don't need a strong resistor, but I don't know an exact value so you may need to try multiple types between 75 ohm to 500 ohm.