Neo geo cd RGB + rgb newbie

Started by geodeath, August 19, 2004, 05:43:16 PM

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geodeath

Hello everybody.
I just bought a japanese NTSC neo geo cd (toploader).
Since i live in Europe, Greece, i need a different ac adapter (thats easy) and an rgb cable so i can view everything in color. Is the neo geo AV port pins really the same as the neo geo cd?

then, which pins should i connect for the cable to work?

There are Audio, GND, VID, RED, GREEN, BLUE, SYNC, +5v..

which of these all are needed for the cable to be compatible to a TV? (not a vga monitor).
thanks!
george
:ph34r:  

NFG

To answer this question, you need RGB, Sync + Gnd.  Any other signals - audio, +5v, or video instead of sync - depends on your display and your needs.

To answer the question you emailed me:

You're confused.

The Genesis2 has a 9-pin miniDIN for RGB, the NEO CD has a 4-pin miniDIN for S-video (An international standard plug).  The RGB connector on the NeoCD (And Neo cart) is an 8-pin DIN (not mini) that is ALMOST the same as the Genesis1 - the top pins, 6 + 7, are spaced differently.  One is round, like a vertical C, the other is more U shaped.  They use the same pinout, but because of this pin spacing difference you'll have to either bend these two pins or make a different cable.

geodeath

I just need the cable to be compatible with a euro scart TV.
nothing more.

So i ll need Red, Blue, Green, video, Gnd and  audio only?

i dont know, but i guess that the +5 and the sync signals are for the vga only.

Maybe you should add this info to the rgb primer too?

NFG

As I said, whether you need the Video or Sync depends on your display.  Whether you need the +5v depends on your display.  SCART isn't a solid standard, there's a lot of variation between models and implementations.  There are lots of topics on these forums discussing this, I suggest you search for SCART and see what you get.

geodeath

I made an rgb cable that works in a certain television, but it does NOT go into rgb mode by itself, instead i have to go into av mode to see the console signal, but its rgb clear.

The same cable however does not work at all in another television 9sound works though), but when i switch the console off, it DOES show something for a fraction of a second.

I am thinking about switching the composite video for the sync signal, but if i do this, i am afraid i will come across a tv that wont work with this either. So, what do companies that make such cables do? I could use a switch for these two signals, but how does company cables work?

geodeath

After some testing, i found that no matter what kind of combination between composite video or composite sync or +5 (cause as you said its all a matter of display) i still wont get real rgb (the tv wont switch by itself unless +5 is connected and no color at all with some combinations).

The only thing i havent done, is to solder the RGB grounds to the ground pin. Is this needed? Sorry if its  a dumb question but i have to ask it after all this testing.
thanks
George

NFG

As a general rule, all grounds should be connected.  Some devices use this as a sensor to determine the input type, some don't.  There's no reason NOT to do it, but there's a good argument to be made against leaving them disconnected, so do it.

Quoteit DOES show something for a fraction of a second.
This is common when your RGB lines require capacitors, for example with the PAL GameCube.  Slap some 220uf caps in each of the RGB lines and live happy.

Yes, some TVs require voltage on proper pin to enable SCART mode, some don't.  Wire it up, live happy.

geodeath

I just followed the neo to scart cable schematic in the hardware book.
some guys in a neo geo only forum told me i need a 100ohm resistor in order for the +5 to drop. They say its important for some tvs and stuff. First thing i will test is the grounds. Then, probably the resistor. Then the capacitors. I ll keep posting, thanks for the input. all input are valuable. :D  

geodeath

#8
Well, after soldering a 100ohm resistor in the +5 line, my tv showed the signal correctly, and it switched to scart by itself. But, after soldering all cables together (i just had them twisted around just to see how they work) it still wont work.

I also used a single 220uf capacitor on each RGB line and it still wont display.
If ANYONE did such a cable succesfully, i would really LOVE to hear what they ve done. The tv is 100& compatible, i own a lot of consoles i use rgb cables with, with no problem at all.

I am almost ready to quit making this @#%$!# cable. I just cant figure HOW can something work only once when i tried the pins one by one with a multimeter for continuity.

Darkman

I didn't make an RGB cable for Neo Geo, but I did make one for my Dreamcast. The trouble was that none of my TVs worked well with 5V on SCART pin 8. I also needed to solder a resistor between SCART pins 8-16 to get any video at all. Furthermore, I found using composite sync to give good results with autoswitching.
I also had problems with audio not working when the cable was fully assembled. Probably shorted the wires with ground. My advice - solder everything carefully, cover problematic spots with electric tape to prevent shorting.

geodeath

After crashtesting the cable i finally did it as i should, but now the picture is rolling and the audio missing. Some guys on a dedicated neo geo forum, said that pin 8 is not nessecary at all, and i noticed no difference connected or not. the autoswitch works fine, its just rolling. They said that rolling is a problem of sync, so i should try the sync or video pin again.

thanks