Andy Vandenberghe
Level 1 (33 points)
Mac OS X

Q: imac screen grey with vertical stripes

hi,

i have an imac 24' late 2009 silver, and sometimes the screen suddenly "switches off" and shows a grey screen with thin vertical lines about 1cm apart.  this happened twice this month now, usually when the mac was switched on for a few hours. What can it be ? is the screen broken ? Should i reinstall everything ?

iMac Intel Core 2 Duo silvery model, Mac OS X (10.6.7), 4gig ram, 500 gig HD

Posted on May 10, 2011 3:52 PM

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Andy Vandenberghe

Q: imac screen grey with vertical stripes

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  • by rkaufmann87,

    rkaufmann87 rkaufmann87 May 10, 2011 4:08 PM in response to Andy Vandenberghe
    Level 9 (58,956 points)
    Photos for Mac
    May 10, 2011 4:08 PM in response to Andy Vandenberghe

    You should run some diagnostics to see if you have a hardware issue first. Where I'd start is running Apple Hardware Test in Extended Mode. It isn't the best test available for testing hardware however it does uncover some problems. If you get an error code you can post it here or Google it to get a clue what it means.

     

    You can also do some basics such as restarting in Safe Mode and doing a SMC and PRAM reset however I don't think those will help from the way you are describing the problem. Resetting both the SMC and PRAM is simple though and it can't hurt.

     

    SMC RESET

     

    • Shut down the computer.
    • Unplug the computer's power cord and all peripherals.
    • Press and hold the power button for 5 seconds.
    • Release the power button.
    • Attach the computers power cable.
    • Press the power button to turn on the computer.

     

    PRAM RESET

     

    • Shut down the computer.
    • Locate the following keys on the keyboard: Command, Option, P, and R. You will need to hold these keys down simultaneously in step 4.
    • Turn on the computer.
    • Press and hold the Command-Option-P-R keys. You must press this key combination before the gray screen appears.
    • Hold the keys down until the computer restarts and you hear the startup sound for the second time.
    • Release the keys.

     

    Roger