Matrox Corona Installation And Hardware Reference page 66

66 Appendix A: Troubleshooting
When I run an application, there is no picture on my video
display. The monitor is blank.
The application you are running might be attempting to select
a resolution that isn't supported by your monitor. Check your
monitor's manual for supported resolutions.
The colors are wrong.
Incorrect colors indicate that either the cabling (for monitors
that do not have a built-in cable) or the monitor impedance is
incorrect.
Ensure that the red, green, and blue lines are connected to
the corresponding red, green, and blue monitor inputs (some
monitor input connectors are not in the expected order).
Make sure your monitor's RGB inputs are set to 75 ohms.
Several monitors have individual switches to set the
impedance of the inputs. Make sure that they are all set to
75 ohms.
On some PCs, you must run a setup program or set DIP
switches to select the main video adapter type. For most PCs,
you should select an EGA/VGA type. Refer to the user manual
for your computer.
Check the cable continuity.
The display is not centered.
Adjust the centering control of your monitor to position the
picture on the screen (refer to your monitor's manual).
The picture quality is poor, with a dim picture, poor
contrast, and poor sharpness.
The monitor might be improperly adjusted.
Adjust the brightness, sharpness, and contrast controls of
your monitor.
Ensure that the cable is correctly and completely inserted at
both ends.
Make sure that the RGB input switches are set to 75 ohms.