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Mac Tech
Mac Tech, Apple Specialist
Category: Mac
Satisfied Customers: 1597
Experience:  7 + Years Supporting Apple Products
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I have an Apple 24 Cinema HD monitor. The monitor is attached

Customer Question

I have an Apple 24" Cinema HD monitor. The monitor is attached to my 15" Macbook Pro.

All of a sudden the monitor display is black. However, when I open the laptop, the monitor's display opens.
Submitted: 6 years ago.
Category: Mac
Expert:  Mac Tech replied 6 years ago.
Hi, and thanks for using JustAnswer.

Add this page to your Favorites/Bookmarks first, so as to get back to me anytime later on, if needed.

Did this occur while you were using your Mac, or did it go to screen saver and/or did you reboot and the monitor was dark?
Customer: replied 6 years ago.
The computer was in sleep mode. When I went to "awake" it, the monitor display stayed black. The on light of the monitor keeps pulsing.
Expert:  Mac Tech replied 6 years ago.
If your display goes black you can go to the prefs and click "detect displays". You can also select show display on menu bar in the display prefs and you can do it from there.
Customer: replied 6 years ago.
That does not solve the problem.
Expert:  Mac Tech replied 6 years ago.
What version OS X is running on your MBP?
Customer: replied 6 years ago.
Expert:  Mac Tech replied 6 years ago.
Please unplug the power cable from the back of the Cinema display, and plug it in again while the laptop is on (do not remove any cables from Cinema display connected to the laptop).
Customer: replied 6 years ago.
Expert:  Mac Tech replied 6 years ago.
You're back up and running now?
Customer: replied 6 years ago.
Expert:  Mac Tech replied 6 years ago.
After performing the following, if the display still does not come alive, go to preferences and detect display.

  1. Shut down the computer.
  2. Locate the following keys on the keyboard: Command, Option, P, and R. You will need to hold these keys down simultaneously in step 4.
  3. Turn on the computer.
  4. Press and hold the Command-Option-P-R keys. You must press this key combination before the gray screen appears.
  5. Hold the keys down until the computer restarts and you hear the startup sound for the 2nd time.
Release the keys and let the computer start up.
Customer: replied 6 years ago.
I will get back to you.
Expert:  Mac Tech replied 6 years ago.
Very well. Please let me know how this goes. Thank you for your patience.
Customer: replied 6 years ago.
It did not work. I had to take it to Apple.
Expert:  Mac Tech replied 6 years ago.
Thank you for your reply.

Was the issue with the External display OR your Macbook?