I bought a used monitor to go with the Mac IIcx - a 12" RGB display and it just keeps giving me a snowy screen. I've tried setting it to different colorsync system profiles, resetting the PRAM, checked all my connections and cords, installed all the drivers in system 7.5.5, still get snow. The computer works with a 14" RGB "high-res" display. Is there some incompatibility I don't know about???