Blank screen monitor a90f+ screen is blank when I turn on the monitor the green light appears then turns to an amber color and the screen remains blank.

Normally, monitors will show green (or other color) when there is a video signal available.
Amber is fairly common to announce 'I'm here if you need me.'

When you
When you power up your computer and the monitor screen remains dark, the problem can be either be associated with your monitor, or your computer power supply/video card/motherboard or CPU. Perform the following tests to isolate the problem to either the monitor or the computer.
1. Turn off you PC and monitor. Then verify that the 15 pin video data cable connectors are fully inserted into their receptacles on the rear of your PC and on the rear of the monitor and they are tightened down. (on some monitors the data cable is hard-wired to the monitor). Then make sure that both your monitor power cable is securely plugged into a working AC power receptacle. (You can temporarily plug a lamp into your AC power receptacle to make sure you have a good source of AC power).
3. Turn on the power switch on your monitor. The amber colored LED on your monitor should come on. Then turn on your PC. The fans in your PC start to run and continue to run and the LED on your monitor should change from amber to green.
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Now if the monitor led remains amber and the screen stays dark you either have a bad monitor or a problem with your video card, motherboard or processor.. Try using a different monitor. If that doesn't solve the problem, you need to have a PC technician test your computer.
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Best regards,
Yavacotech

Best thing to do, hook up another known working monitor to the computer and this will verify that the computer is working properly.

If you get video on the known working monitor when you turn on the computer then you know the computer has a problem.

I think the data wire may be disjoined in the Center. try to replace the data cable and reply me.

dos it work use a new monitor

just check ur lcd display cable and try to clean and c it it will cme

make sure that all the cables are connected FULLY.
blinking light means that there is no signal.

The monitor requires service The monitor is not receiving a signal from the computer

when i turn the computer on the light on the monitor blinks green but i cant get it to turn on..i have a black screen.

Self-Test Feature Check (STFC) Your monitor provides a self-test feature that allows you to check whether your monitor is functioning properly. If your monitor and computer are properly connected but the monitor screen remains dark, run the monitor self-test by performing the following steps:

1. Turn off both your computer and the monitor.
2. Unplug the video cable from the back of the computer. To ensure proper Self-Test operation, remove Analog (blue connector) cables from the back of computer.
3. Turn on the monitor. The floating 'Dell - self-test Feature Check' dialog box should appear on-screen (against a black background) if the monitor cannot sense a video signal and is working correctly. While in self-test mode, the power LED remains green and the self-test pattern will scroll through the screen continually.
   
4. Turn off your monitor and reconnect the video cable; then turn on both your computer and the monitor.

If your monitor screen remains blank after you use the previous procedure, check your video controller and computer system; your monitor is functioning properly.

Thanks
proton