Apple Mac Pro (Early 2008) - Manual (Page 73)

Chapter 4 Problem, Meet Solution 73
If no image appears on the screen
 Make sure the display and computer are turned on.
 Make sure the cables are connected properly to your computer and the display.
 If your graphics card has an internal power cable, make sure it’s connected to the
card and the logic board.
 Make sure your computer is not in sleep. Press the power button or any key to see if
the computer wakes.
 Make sure the display brightness and contrast are set properly. Use the brightness
keys on the Apple Keyboard. Some displays also have brightness and contrast
controls on or under their front edge or on the side.
 Reset the PRAM by restarting the computer while holding down the Command (x),
Option, P, and R keys until you hear the startup sound a second time. Then start up
using the software installation disc that came with your computer.
If the screen image appears dim or flickers
 Adjust the display brightness and contrast settings. Use the brightness keys on the
Apple Keyboard. Some displays also have brightness and contrast controls on or
under their front edge. Or you may be able to adjust brightness or contrast using the
Displays pane of System Preferences.
 Calibrate the display by choosing Apple () > System Preferences. Click Displays,
select Color, and click Calibrate. For more information on color and your display,
see Mac Help.