iMac acting up. Garbage on screen.

Discussion in 'iMac' started by mdgolom, Jul 17, 2012.

  1. mdgolom macrumors 6502

    Oct 26, 2006
    My early 2009 iMac (2.93ghz 24") has started to act up lately.

    It first started with the mouse not working. It's almost as if the left mouse button wouldn't work. I was able to right-mouse click and it worked. I swapped mice and that didn't help. For the most part if I put the computer to sleep using then power button the pushed it again the mouse would start working.

    It took a turn for the worse last week and started showing random clusters of single pixels. Also I would see issues where the screen wasn't refreshing completely and I would see blocks of the screen that didn't belong. Most of the time when this happened the system would freeze. The mouse pointer would move but I couldn't get a response to anything until I powered off the machine. Twice when this happened I also got a kernel panic. It seems to happen more when I have external drives attaches which lead a friend to think it might be power related.

    Since I have a good clone of the HD, I went ahead and reformatted the drive and reinstalled 10.6, 10.6.8 and then 10.7. Even after this I am still having problems.

    I'm guessing the problem is the video card or logic board, but I'm curious if anyone has seen this problem before. If it's the video or logic board, I'm not sure it's worth fixing.

  2. TurnTronics macrumors member

    Jun 15, 2012
    Cincinnati, OH
    From my experience working on 1000s of iMacs over the years, it sounds like a GPU/Logic board issue. Your best bet would be to take it to the Genius Bar and have them diagnose.

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