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 a PC) look nice but compounds the DC brightness issue. For the PC I have the D9200 brightness set at 65-70. With the DC, setting the brightness above 200 still is not very bright (without the plexi). Soul Calibur looks decent. Ferrari 355 is still dim. Is this typical of the DC vga output? Is it the Dreamcast VGA Cable? Is there a way to boost the brightness?
-----Update-----
My brightness problem ended up being caused by a KVM switch and was made worse by the dark plexiglass I have in front of the monitor. The dreamcast does not work with two different belkin types of KVM switches I have. One makes it dark the other produces a blue tint. Without the plexiglass and the KVMs, I was even able to get the Lightgun to work.