RCA being the old plugs used for consumer AV, right? Most old arcade monitors/setups used an RGBS (red, green, blue, sync, and of course ground) signal at 15kHz. That's what Jamma is wired for. IDK about Area 51, whether it was slightly higher resolution? 15kHz is 320x240p or thereabouts, 25kHz is somethingx384p and 31kHz is 640x480p. 31Khz VGA was normally wired as RGBHV through the HD15/DB15 plug we all know and love.
With the above in mind, what is your RCA video source? And is it outputting RGB of some form? And if so, does the resolution match your monitor's input range?
EDIT: wikipedia tells me Area 51 outputs video at 320x240p = 15kHz. So what is your RCA video source?