Naomi + Sega 838-13683-02 JVS I/O video issues

[pzlate]

So I dunno what's up but on my CRT I will get these dark horizontal bars across the screen around big images like the CVS2 logo or capcom logo. Also my capture card can't capture the RGBS signal directly, with a sync cleaner I get an unstable picture.
here's a video, you can see the darkened area on the title screen.

I have a 1K ohm pot on my sync line and pots for RGB also. I have no issues with my supergun video output with my CPS3, can capture directly off jamma RGBs without a sync cleaner.

Do you think I need to increase the ohmage on the sync line or maybe some caps need replacing on my JVS i/o?

e: So I tried running it at 31Khz through my i/o to my capture card. Sync is fine at 31Khz, and I don't need a sync cleaner but I still get the darkened bars around bright things/logos etc. This makes me thing it's definitely I/O related, I just dunno what it could be.

 

[skate323k137]

If anything I would use less resistance on the sync line. I usually only use 220 or 330 ohms. Typically I use 220 ohms on all 4 signals (R G B and Sync) Honestly though sync looks stable so I'm not sure where your issue lies there. Does your capture card accept VGA? You may be able to just split the VGA out from the NAOMI to your capture card, and to another display (or the IO) if that's needed. Basically try to avoid having the IO amp the video just for you to try to knock it back down, when you already have a VGA source to begin with. I have a WWF NAOMI cabinet with 2 monitors and sega just wired VGA split directly to both monitors from the factory (no circuitry aside from just splitting it).

 

[pzlate]

Well I need 15Khz RGBS for my Sony BVM, I've tried two extron boxes to combine the sync but never had any luck with them. I'd still like to get rid of the dark bars around things from the i/o even if I do go the splitter route. My capture card is the internal version of the xcapture-1 the SC512. Supports RGBs and RGBHV.


e: Oops my JVS I/O isn't the Rev B it's this one with surface mount caps. the Sega 838-13683-02

http://wiki.arcadeotaku.com/images/c/c3/Sega-io-838-13683-02-pcb.jpg

In the mean time I just set up a VGA CRT for 31Khz. Naomi looks a lot better in 31Khz anyway, and I won't have to mess with my Horizontal/Width adjustments.