iMac 24 inch with chime but black screen

Discussion in 'iMac' started by Poeter, Jun 17, 2014.

  1. Poeter macrumors newbie

    Joined:
    Dec 13, 2011
    #1
    Hello everyone,

    I have a iMac 24-inch 2009 3,06ghz version. When i press power screen stays black. I hear a chime fans etc.
    Only led1, led2, led3 are green. led4 stays off, tried another working lcd but it won't help.

    Any ideas, what can i do, what can i try?
    Someone with board level experience here?

    Help:confused:

    Regards Peter
     
  2. Altemose macrumors G3

    Altemose

    Joined:
    Mar 26, 2013
    Location:
    Elkton, Maryland
    #2
    GPU or LCD cable failure seems to be the cause. You can get Apple to do a full diagnosis at a Genius Bar as anyone on the Internet can just guess at what the problem is.
     
  3. Intell macrumors P6

    Intell

    Joined:
    Jan 24, 2010
    Location:
    Inside
    #3
    LED 4's failure to light means that the GPU and LCD are not communicating. If you want Apple to fix that, you have until October of this year. After that it will be a "Vintage" product and they won't service it unless it was bought in California and you are having it serviced in an Apple Store in California.
     
  4. Altemose macrumors G3

    Altemose

    Joined:
    Mar 26, 2013
    Location:
    Elkton, Maryland
    #4
    Is that more commonly a bad cable (perhaps due to removal) or a bad GPU? OP swapped the LCD so I doubt that is it!
     
  5. Intell macrumors P6

    Intell

    Joined:
    Jan 24, 2010
    Location:
    Inside
    #5
    The GPUs in that iMac, the NVIDIA GeForce 9400M, GeForce GT 120, GeForce GT 130, or ATI Radeon HD 4850, aren't known for failures. LED #3 indicates that the GPU and logicboard are communicating. That reduces the chance that the GPU is the problem. The cable could be the problem depending of if the LCD was ever removed before it started presenting this problem.
     
  6. Altemose macrumors G3

    Altemose

    Joined:
    Mar 26, 2013
    Location:
    Elkton, Maryland
    #6
    I only ask because the connector on the cable could have been damaged by accidental inappropriate handling while removing the display.
     
  7. Intell macrumors P6

    Intell

    Joined:
    Jan 24, 2010
    Location:
    Inside
  8. Poeter thread starter macrumors newbie

    Joined:
    Dec 13, 2011
    #8
    I have 3 imacs here, all the same issues.
    I have one working imac as well. In this imac the lcds work.
    So it must be logic board and not gpu since i ruled that out already.

    So i need a logic board fix for led4 and i don't know where to start.

    Regards, peter
     
  9. Intell macrumors P6

    Intell

    Joined:
    Jan 24, 2010
    Location:
    Inside
    #9
    LED 4 doesn't indicate a logicboard failure, that's LED 2 and 3 both of which are lighting up correctly for you.
     
  10. Poeter thread starter macrumors newbie

    Joined:
    Dec 13, 2011
    #10
    I have a working iMac, on that iMac i have tried the LCD Screen and LVDS Cable and temp sensor. On that iMac all the screens work.

    On the other iMacs LED4 stays off.

    Don't know what to do anymore...

    Regards, Peter
     

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