- Since each of these steps represents a possible solution to this issue, check the display function after completing each step.
- If model-specific information is required to complete any of the steps in this solution, refer to the operating instructions supplied with the monitor. Manuals are posted on your model support page.
- Disconnect the computer and monitor from any surge protector or power strip and plug it directly into a known working wall outlet.
NOTE: If the display returns after completing this step, the problem is isolated to the surge protector or power strip.
- Verify the correct video cable adapter is being used, and that the adapter settings are appropriate for the desired display resolution.
NOTE: For information regarding connectivity between a Digital Video Interface (DVI) monitor and the Apple Display Connector (ADC) interface on an Apple Macintosh computer, please refer to the Apple website at http://www.apple.com.
- Ensure the monitor cables are correctly connected .
- Ensure the keyboard and mouse are connected correctly.
- Adjust the monitor brightness and contrast levels.
- Perform a monitor self-test.
- If possible, connect and use the monitor with a different computer.
NOTE: If the monitor functions properly, then the problem is isolated to the computer to which the monitor was originally connected.
- Troubleshoot the computer display configuration.
- Remove any hardware that has been added to the computer, including any added memory, internal or external drives, and any type (network, sound, video, USB, etc.) adapter card.
NOTE: Some Apple Macintosh computers may experience display problems if the battery in the computer needs to be replaced.
The troubleshooting steps listed above should resolve your issue. If you have completed all of the steps and the issue is not resolved, service may be required.  Go to Product Repair.