Snes NTSC RGB - image issue with bright white

[Zapf]

I got bit by the RGB bug and went about buying all the shit I needed to set up my snes, genesis and sega saturn for rgb output. I have some minor issues though, and I am trying to figure out where the problem is exactly.

My setup-
US NTSC SNES, Genesis, Saturn
3rd party RGB SCART cables - Saturn and SNES bought from electric quarter, sega model two bought from pcenginesales on ebay.
RGB->YUV Transcoder - cvs 287, bought from ebay. Looks like a knockoff of the csy 2100
Component cable - monoprice rg6 component (quality stuff) - also tested with cheap phillips cable from walmart

My issues
-On the genesis, there is some noise appearing at the bottom of the screen in the sonic games (tested with 2, 3, knuckles) - just the bottom row of pixels seem to be flickering random colors at times. Not a real big problem to be honest, I didnt notice it in vectorman or virtua racing.
-main problem On the snes, I get this image tear on really bright white screens. This is from contra III, the Konami logo and the intro with the big explosion

EDIT: Also checked on super metroid - does it during the first large explosion while you are doing crystal flash

This happens only on my LCD (Sharp aquos 32 inch LC-32E67U) - I ran upstairs and tested on the component input of my older magnavox 27 inch crt, and it was fine.

So, is this solely a problem with my tv? I dont have this problem with the component out of my wii emulating contra III or any other game with the konami logo. I've tried with the official snes AC Adapter and with a third party one, and two different snes's. I'm using an ac adapter from sprint for the transcoder - it matches the voltage/amp requirements and worked well for another user on a different forum. I could try changing that out if anyone could recommend a source. Is there something I could adjust in the transcoder that could solve this? I know it has several variable resistors in there and from what I've read you can adjust three of the five for R, G, B color balance.



One more problem - could someone reccomend a good scart switch (pref with seperate audio out). I got this philex one http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... 0444002858 and while the 2nd and 3rd inputs work fine, the first one appears to be missing one of the fucking colors =((( (when using the switch, im using one of those sony male male scart cables I paid way too much for on ebay).

[Zapf]

Tried with another ac adapter - same issue. Could this be an issue with my snes rgb cable? Its one of those advertised to be compatible with pal gamecube, so I presumed it had the appropriate capacitance added to the r g and b lines for ntsc snes usage.

[viletim]

Tried with another ac adapter - same issue. Could this be an issue with my snes rgb cable? Its one of those advertised to be compatible with pal gamecube, so I presumed it had the appropriate capacitance added to the r g and b lines for ntsc snes usage.

That's important info. Compare the cable diagrams at:
http://members.optusnet.com.au/eviltim/ ... escart.htm

You need to open it up and remove the 75 ohm resistor (and possibly capacitor) on the composite video line.

One more problem - could someone reccomend a good scart switch (pref with seperate audio out). I got this philex one http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... 0444002858 and while the 2nd and 3rd inputs work fine, the first one appears to be missing one of the fucking colors =((( (when using the switch, im using one of those sony male male scart cables I paid way too much for on ebay).

I have one which looks identical to the picture in this auction. It's well built and works fine. It had Philips written on the box it came in, not that this really means anything...

[Zapf]

I just opened it up, and there is no 75 ohm resister or cap on the component wire - it looks just like that diagram says for a us snes =/

[Zapf]

buuuuuuuuuuuuut im readin the tiny text on the caps on r, g and b, and they only appear to be 100uf, instead of the recommended 220uf - is this a possible culprit?

[andy251203]

On my jamma SNES I use 220 uf caps and no resistors. The picture is a little dim, but it's not an issue on an Egret where I can just crank the brightness up. Never tried it on an RGB television.

[Zapf]

I got a new cable with the higher capacitance on the r g and b lines, and its workin great now. Got another problem though. I got a kramer fc-14 cheap and I want to start using that, but from what I've discussed with others, it needs its sync clean, so I will have to strip it from the composite line with an lm1881n chip.

Whats the best way of implementing the lm1881n circuit in my setup (3 consoles -> scart switcher -> kramer fc 14 -> tv) am I going to have to fashion some sort of scart -> db9 cable like in that gamesx tutorial, can I put this in a project box seperately (would be preferred if possible) with comp in / sync out, or is there another option.

[Zapf]

alright, I got the sync cleaner circuit assembled. It works with the "amplified" composite output from my scart switch, but not from the unamplified output or the composite lead from my scart -> 6 rca cable.

However, im gettin the same problems with snes again as I did in my OP =/ Its worse with the original cable, which makes me think it might be solved by some higher capacitance caps on r g and b.

[Zapf]

Ok, that actually worked. I think I used 470 uf caps (the next highest size at radioshack). I'm havin a hard time tellin the difference between it and my cheap converter though - maybe my tv isn't good enough to make make any improvements noticeable =/

I'll continue experimenting =)