BTW if you mess up and get to where you can't see the screen to fix it, just hold the MENU button for 5-seconds, while unplugging the unit, keep holding for 5-seconds while it is unplugged and while still holding it, plug back into the power for 5 seconds, and it should revert to base settings of 480p full-screen.
Also, as stated in the update on the original post, if you leave the unit unplugged for too long, it can loose your custom settings, so is probably good to jot them down on paper.
When you click MENU, you will see a bunch of options, and here are the suggested ones to adjust and settings:
Contrast: 50
Brightness: 48
Color:
Red - 38
Green - 46
Blue - 48
Size: Panoscan (4x3)
*Note - if you want to force widescreen select "Full" here, as your TV might not be able to override it with the normal controls since the box pads the sides with black to achieve normal width while in 4x3.
Output: 1080p, 1080i, 720p, 480p as you wish in 60Hz (NTSC) or 50Hz (pal)
Why is the all the color stuff necessary? Good question. All I can figure is that the original NTSC1953 colorspace the Dreamcast works in is getting lost when it goes through the box to HDMI and your TV is assuming it to be sRGB.
Anyway, hope this is helpful
