¿Using a SNES as a RGB to NTSC converter?

[master higgins]

Hi, sorry if my first post is a question, but I've been wondering if one can use a SNES to convert from RGB to NTSC. With my graphics card i can output resolutions with 15khz of horizontal frecuency and 60hz vertical frecuency, so the frecuency incompatibility is solved. What I want to know is where to solder the red, green, blue, sync (be either composite or splitted into horizontal and vertical) and the ground for the red,green,blue and sync signals.

I know that the SNES has an IC which does this, some talk about the CXA1145, but in my SNES I only found a BA6994AF IC. It has the same amount of pins than the CXA1145, so I assumed (the risk) it had the same pinout. I tried connecting the red (pin 1 vga), green (pin 2 vga) and blue (pin 3 vga) signals to pins 2, 3 and 4 of the IC respectively. Pins 13 and 14 of the vga cable were connected to pin 10. Pins 6 (vga red gnd), 7 (vga green gnd), 8 (vga blue gnd), 10 (vga sync gnd) of the vga cable and power supply gnd were connected to pin 24 of the IC. I made bridges between pins 15 and 17 and between pins 16 and 18 of the IC, to make the Luma/Croma conversion to Composite video. Then i connected pin 19 to +5V. Finally, i connected an RCA plug with the positive ending to pin 20 of the IC and the gnd ending of the plug to pin 24. The result was a black & white image with some interference.

If someone knows where to input these signals in some of the IC's of the snes board I would appreciate it infinitely :):)!!!

PS: I noticed that turning the SNES on without a cartridge inserted and the console connected to the TV through RF shows a progressive video output (OK, it's just a black screen, but when you put some of the TV menus, like volume or color/tint/brightness/etc, you can appreciate scanlines in the letters, so it still outputs video to the TV