Planning to build NTSC SNES RGB cable

[mesmer]

Hi All, I'll be building a cable to connect my NTSC SNES up to my cab soon. Just wanted to run it by you all to make sure I'm not missing anything.

My monitor is a Nanao MS-2930. It has an HD15 port input and is selectable via dip switch between 'jamma' input levels and 'vga' 75ohm-terminated levels. My goal is to build a vga box like device, similar in shape to a dreamcast one. I'll get a normal snes av cable to sacrifice for the connector, hopefully I can find one with all the pins. I plan on putting 220uf electrolytic caps on the RGB lines, pins 1, 2, and 4 on the SNES side, + towards console. I'll run csync directly from pin 3 on the snes to the hsync pin 13 on hd15.

I know 'PC / VGA'(DC) is not the exact same spec as 'SCART RGB'(AC coupled) However, I'm using coupling caps on my PS2 RGB connection, also the dreamcast vga box has them, and they both work fine on my monitor.

I know the SNES2 does not do RGB, but I heard (here or somewhere else?) that some of the later SNES1 models did not do RGB. Something about weather 'eject' on your eject button was printed or molded. Anyone know about this?

Thanks

[bryan_c]

You might be thinking of this post?

The eject button can tell you if you have one of the earliest models (which should output RGB) or not. The latest models allegedly don't support RGB (according to kamiboy in the XRGB-3 thread).. The revisions in between I'm really not sure about, but you'd need to crack open your system to tell these middling revisions from the later ones.

[mesmer]

Thanks! I'll try to crack open my system before I buy the stuff.

[SGGG2]

SNES2 can be modded for RGB and has a much sharper signal.

http://www.gamesx.com/rgbadd/snes2rgb.htm

[RGB32E]

I've performed the SNES2 rgb mod and it outputs a brighter and sharper image than my oldest/original SNES, but not as good as a later model SNES (with modeled eject lever).

Also, as discussed with Lawrence, the SNES2 RGB mod only needs a series 75 ohm resistor between the rgb outputs on the encoder chip and the SNES av output connector to work. A small cap to ground could be added but the linked circuit shows none of this!

SNES2 can be modded for RGB and has a much sharper signal.

http://www.gamesx.com/rgbadd/snes2rgb.htm

[mesmer]

I couldn't find an AV cable locally that had all the pins, so I went ahead and ordered the SCART cable from play asia. I'll just replace the scart connector with an hd-15 and audio connectors.

I didn't realize I need a security bit to open up my SNES. It's the later molded button one, hopefully it has RGB. Maybe I'll try the melted pen trick.

[Jockel]

Maybe I'll try the melted pen trick.

I can't recommend that. Worked a few times for me, but when the pen breaks off, you're pretty much fucked.
Trust me, that money on a gamebit is well spent.

[ZOM]

What Jockel said.

But if you really can't get a gamebit, and happen to have a spare "cheap" flat screwdriver at hand, you can just file down the center part until it forms a "fork" - and there's your gamebit.

Also, just a heads up, you might have come across fancy looking security-bit sets of almost all sizes in shops... yeah, the reason I used italic text is of course because exactly the size you're looking for is nowhere to be found in such a set. (Unless it's specifically sold as a game-bit set)

[mesmer]

Ah ok, won't waste my time with that then. I'll just build the cable and hope it works. If it doesn't I'll just trade it in for another one.

[mesmer]

I built the cable successfully a while back and took pictures, better late than never:

Ended up buying this cable: http://www.play-asia.com/paOS-13-71-24-49-en-70-64.html I couldn't find a normal AV cable locally that had all the pins. I had hoped that buying an RGB scart cable would save me from opening up the SNES connector side, and just re solder the SCART side. After testing with the multi meter, I found that the cable did not use the SNES pin 3 for +12v, which I wanted to use for CSYNC on my ntsc snes. I guess it is made to be compatible with the PAL N64 which does not have +12. So I had to open up the SNES connector side, this was a chore:








Much worse than expected. Ok here it is all soldered up:





Some parts:


Testing:



It's alive:



(Sorry not a shmup =)

It's a late model SNES1, but does do RGB:


Some more of the cable:




I was going to put in in a project box, but got lazy, and just trimmed the legs, and covered the exposed parts w/ hot glue.
Still haven't done the pad-hack, need to find some cheap controllers