How to troubleshoot an incorrect display on the monitor

IMPORTANT:

• If model-specific information is required to complete any of the steps in this solution, refer to the operating instructions supplied with the product. Manuals are posted on your model support page.
• This procedure must be performed while logged in as Administrator or to an account with Administrator rights.
• Some monitors must be turned on after the computer is turned on.

1. Degauss the monitor by turning the monitor off, waiting a few seconds, and then turning the monitor back on.

   NOTES:

   • This may need to be done several times before a degauss is successful.
   • Some monitors may require up to 20 minutes between degaussing for an optimal effect.
2. Reset the monitor to factory defaults.
3. Configure the monitor in VGA Mode.
4. Verify the correct monitor resolution is selected in Display Properties.

   NOTE: If the monitor is a CRT (Cathode Ray Tube), it may be necessary to adjust the monitor refresh rate to eliminate flicker.

5. Ensure the color depth is at least High Color 16bit.
6. Remove any large electrical devices or speakers from the vicinity of the computer.

   NOTE: This includes devices plugged into the same power strip as the monitor.

7. If using a CRT (Cathode Ray Tube) monitor, turn off any fluorescent lighting.
8. Disconnect and reconnect the monitor to the computer, ensuring there are no bent pins or broken connectors.

   NOTES:

   • If using an available BNC connection for the monitor, ensure the 5 BNC connectors are in the proper order, red, green, blue, horizontal synchronization, and vertical synchronization.
   • For monitors which support both a BNC and a HD15 connection, ensure the monitor is configured to use the current connection type.
   • For monitors using both an analog and a digital connection, use only one connection type to the computer.
9. Wiggle the video cable where it connects to the monitor to ensure the cable does not have a short. If this causes the problem to go away and then come back, the monitor may need to be serviced.

   NOTE: If a video pass-through card is used, bypass the video pass-through connection and connect from the monitor directly to the video card. If the problem is resolved the video pass-through connection may need to be replaced. Contact the manufacturer of the video pass-through hardware.

10. Remove any video extension cables.
11. If available, perform a monitor self-test to ensure the monitor is functioning correctly.
12. Try the monitor in a different room. If successful, suspect an EMI (Electromagnetic Interference) or AC voltage problems in the original room. A line conditioner can be purchased from a local retailer to help resolve voltage problems.

    NOTE: A line conditioner is not guaranteed to resolve this issue.

13. Try the monitor on a different computer.
14. Perform a system restore  to a time when the computer was functioning properly.
15. Restore the video drivers.