Re: RGB->NTSC

[lius@gandalf.rutgers.edu (S. Liu)]

irsman@iastate.edu (Ian Schmidt) writes:

>>Would anyone know how to construct a cable from the RGB output of the
>>IIGS to an NTSC monitor? I guess this is what's built in to the IIGS,
>>but I need an external cable. 

>This isn't a matter of a cable; you need circuitry to correctly combine the R,
>G, B, and sync signals into a properly-timed composite color signal.  Motorola
>makes a chip that does this; indeed, this is what Apple did to get composite
>output on the GS.

>I guess my question would be, why do you need to do this externally as opposed
>to simply using the GS's own composite out?

Actually, my problem is a defective Video Overlay Card. I purchased it a fwew
weeks ago. It outputs full color overlays through the RGB port, but the
overlays are grey through the NTSC jack. I need the card pretty fast for 
a video project, so I'm stuck with this one.

I was hoping for a quick cable or schematics so I could just record off the R
RGB signal. I'm not sure why the overlays don't come out in color, while the v
video picture does, through the NTSC jack. The Control Panel is set to color,
and everything works perfectly on the monitor.

Well, any help appreciated,
Steve