Troubleshooting
Check the following before calling for service.
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Is the power cord of the display connected?
Is the power indicator light on?
Is the power on and the power indicator green?
Is the power indicator amber?
Do you see an "INPUT SIGNAL OUT OF RANGE" message on the screen?
Do you see a "NO SIGNAL "message on the screen?
Check and see if the power cord is connected properly to the power outlet.
Press the Power button.
Adjust the brightness and the contrast.
If the display is in power saving mode, try moving the mouse or pressing any key on the keyboard to bring up the screen.
Make sure if the power is on. 
Try to turn on the PC.
This message appears when the signal from the PC (video card) is out of horizontal or vertical frequency range of the display. Typically this issue can by resolved by restarting the PC with the display connected.
This message appears when the signal cable between your PC and your display is not connected. Check the signal cable and try again.
Do you see a "CONTROLS LOCKED" message on the screen?
Do you see
“CONTROLS LOCKED” when you push MENU button?
You can secure the current control settings, so that they cannot be inadvertently changed. You can unlock the OSD controls at any time by pushing the MENU button
and 
button for 3 seconds: the message “CONTROLS UNLOCKED” will appear.
A10