2009 20" iMac: ¿graphic chipset or screen issue?

Discussion in 'iMac' started by Siannath, Nov 2, 2013.

  1. Siannath, Nov 2, 2013
    Last edited: Nov 2, 2013

    Siannath macrumors member


    Nov 21, 2012
    Lima, Perú
    Hi everyone.

    My cousin has a early 2009 20" iMac, EMC No. 2266, Model No. A1224.

    He lives almost 1000 miles away from the nearest Apple Authorized Service Provider. Hence this post.

    He took his iMac to replace the HDD for a new one. The original one was failing.

    He took it to some computer-repair-guy that obviously never touched an iMac before. I'm saying that because, to open the iMac, he used some crowbar to open it from the back, resulting in all the case severly damaged. A total douche.

    Well, he finally accomplished to replace the HDD. But, since then, the iMac presents some sort of corrupted graphics issue.

    Let me illustrate the situation with some images and a video.

    http://d.pr/i/hnId (image)
    http://d.pr/i/HcrA (image)
    http://d.pr/i/OUi2 (image)
    http://d.pr/i/9ltG (image)
    http://d.pr/v/exaz (video)

    As you can see, there are some green vertical lines on the image. They are everywhere. They appears Lion, on Mountain Lion, even on the installers, even on the boot screen where you select from which drive to boot. Everywhere. So it is not a software related issue. It happens even on the Mavericks USB installer. It happens even on bootcamp Windows setup.

    If you look at the video closely, you will see that the green lines go alongside with the Terminal icon accordingly with the movement.

    I instructed him to use the Apple Service Diagnostics 3S132. The test fail SOMETIMES with the following output:

    72 [Video 2D acceleration test failed]

    There is not other issues. No system crashes, no unexpected reboots, no performance issues.

    So, I am thinking on these possible causes:

    a) A graphics chipset related issue. A hardware failure caused by inappropriate manipulation of the computer. These are graphic glitches, or image corruption, caused by a malfunctioning chipset.

    b) A screen related issue. The screen fails to properly show certain colors. The screen is damaged by inappropriate manipulation.

    c) ???

    So, well, what do you think is the most probable cause of this problem?

    I tell him to bring the computer to an Apple Authorized Reseller, but it is a long trip. He will do it, eventually. But, for now, he required my assistance. He wants to know if it is repairable and how much it could cost.

    Thank you everyone for your comments.

    PD: Sorry about any possible grammar errors or other typos. English is not my native language.
  2. bizzle macrumors 6502a

    Jun 29, 2008
    That test failure in ASD 132 is a bug in that version and not a real failure. I can say with nearly 100% certainty that the LVDS cable was damaged. I can say that with certainty because I've seen that issue many times after an inexperienced tech works on those iMacs.
  3. Siannath thread starter macrumors member


    Nov 21, 2012
    Lima, Perú
    Well, thats very interesting. It seems that the cable is relatively cheap (at least, compared with other options). It may save the long trip to a AUSP.

    Did you recon the graphic glitches?

    Thanks for your help! :)
  4. bizzle macrumors 6502a

    Jun 29, 2008
    It all looks related to the LVDS cable. Before ordering a cable I'd inspect the connector on the logic board for the LVDS connection to make sure no pins are bent and the connector on the back of the LCD. I've once worked on an iMac of a newer generation that has the same type of connector as the back of the LCD of the model you are helping with, but on the logic board side and the damage in that situation was the logic board because it was lifted and damaged. On the model you've got over there the issue is almost always the cable.

    The part number you want is 922-8828. I've used the cable from 2007 and 2008's on those models for testing and it does work as well, but you may as well buy the part that is specified if you want to be sure it's done right.
  5. Siannath thread starter macrumors member


    Nov 21, 2012
    Lima, Perú
    Thank you very much, kind sir :)

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