I started with the consoles forum but this seems more monitor specific.
I have hooked a DC to my D9200 with a Dreamcast VGA Cable.
(
www.jandaman.com/games.mvc?p=dcvgacable&Category_Code=DC)
The games are not very bright, especially Ferrari 355, even with the brightness pushed way up. I have tinted plexi in front of the monitor which makes the mame games (running on the PC) look nice but compounds the DC brightness issue. I have a AracdeVGA card in the Mame PC. For the PC I have the D9200 brightness set at 65-70 with the plexi in place. With the DC, setting the brightness above 200 still is not very bright (without the plexi). Soul Calibur looks decent. Ferrari 355 is still kind of dark. The DC connected to my regular PC monitor yields a much brighter image.
The two suggestion I've had so far are:
" You may need to get a video amp cable to boost the gain...like the one Ultimarc sells."
"Try adding a 220