IBM 689912U Hardware Maintenance Manual - Page 41

Display If the screen is rolling, replace the display assembly. If that does not correct the problem, replace the video adapter (if installed) or replace the system board. If the screen is not rolling, do the following to run the display self-test: 1. Power-off the computer and display. 2. Disconnect the display signal cable. 3. Power-on the display. 4. Turn the brightness and contrast controls clockwise to their maximum setting. 5. Check for the following conditions: You should be able to vary the screen intensity by adjusting the contrast and brightness controls. The screen should be white or light gray, with a black margin (test margin) on the screen. Note The location of the test margin varies with the type of display. The test margin might be on the top, bottom, or one or both sides. If you do not see any test margin on the screen, replace the display. If there is a test margin on the screen, replace the video adapter (if installed) or replace the system board. Note During the first two or three seconds after the display is powered on, the following might occur while the display synchronizes with the computer. Unusual patterns or characters Static, crackling, or clicking sounds A "power-on hum" on larger displays A noticeable odor might occur on new displays or displays recently removed from storage. These sounds, display patterns, and odors are normal; do not replace any parts. If you are unable to correct the problem, go to "Undetermined Problem" on page 81. Service Information 31