Late 2009 iMac Graphics problem..

Discussion in 'iMac' started by Chubaka, Apr 13, 2016.

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  1. Chubaka macrumors newbie

    Joined:
    Oct 10, 2012
    #1
    Hello everyone,
    I have a late 2009 21.5 iMac which had a graphics problem (vertical stripes and later black screen) and eventually I had the graphics chip replaced.
    It worked for around a month then upon booting the screen shows the apple boot and right before login it goes black again. I tried resetting both Smc and NvRam but nothing.
    After a couple of visits to the technician I was told that unfortunately the whole graphics card is damaged and it has to be replaced. I looked around online and the cost is simply insane.
    Now, the weird thing is that when connected to an external monitor the iMac works fine. No chopping graphics I even play games. While connected, the display settings, shows only the external monitor and no other choice. Even more strangely, on occasion but very rarely , after a reboot , BOTH (imac's and external) monitor light up and the external works as an extension desktop .
    Keep in mind that at the time of the gpu repair I removed the cd drive and had an ssd and a second hard drive installed.
    Please help!!
     
  2. Samuelsan2001 macrumors 603

    Joined:
    Oct 24, 2013
    #2
    Could just be a loose screen cable....
     
  3. Chubaka thread starter macrumors newbie

    Joined:
    Oct 10, 2012
    #3
    Please keep in mind that the white screen with the apple logo and the progress bar show every time. It is only after that, that the screen goes black.
     
  4. Samuelsan2001 macrumors 603

    Joined:
    Oct 24, 2013
    #4
    Well if it is your graphics card as the technician said, not much anyone can do, pay to get it fixed or get a new computer seem to be your choices.
     
  5. Chubaka thread starter macrumors newbie

    Joined:
    Oct 10, 2012
    #5
    Samuelsan2001, that sounds correct, but my question is , since the monitor lights up -no backlight or any other screen issue- , and since it plays fine on the external monitor, what could possibly be wrong with the card itself.
     
  6. Samuelsan2001 macrumors 603

    Joined:
    Oct 24, 2013
    #6
    That's where my knowledge is a little sketchy, it could be that the integrated graphics are dodgy and that the external only uses the dedicated graphics chip or even the other way round. Without knowing the spec on the machine I can't even tell if that's a possibility, edit: took a look at the specs for that year and yes 2 graphics cards.

    Try using switchres x to turn off each card in turn and see what works (almost always the dedicated card that dies though) you should be able to turn off the Radeon dedicated card and use the integrated graphics only. To be honest they aren't to different spec wise, the dedicated is better but not vastly superior.
     
  7. Chubaka thread starter macrumors newbie

    Joined:
    Oct 10, 2012
    #7
    Well I did try Switchres X, but it only detects the Ati 4670 gpu (that would be the discrete one) as present and I get the same from the System Report--> Graphics . Is there anything else I could try?
     
  8. stuartak macrumors member

    stuartak

    Joined:
    Feb 21, 2016
    #8
    One thing to consider is if you removed your Optical drive to fit an SSD , did you fit a caddy for the SSD ? As one thing the optical drive case does is form a duct for the cooling air from the Optical fan onto the graphics card heat sink , without the ODD or a SSD caddy the air just blows round the inside of the Imac case and the graphic card overheats and at best rips out . I recently repaired a 27" machine where the owner had removed the Optical and fitted an SSD without anything to re-duct the airflow and the Graphics card ran 30C hotter than it should and kept failing. Fortunately it was not permanently damaged and I made a makeshift duct out of cardboard to re-establish the cooling air onto the heat sink.
     

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