iMac G5 Video card fail Workaround/Fix

Discussion in 'PowerPC Macs' started by DaIceMan, Oct 18, 2010.

  1. DaIceMan macrumors newbie

    Oct 18, 2010
    As many of you know, the iMac G5 has had a bad history of defective electrolythic caps and video chip failures. Naturally I have stumbled across a coulpe of these, one with bad caps and the other with a bad BGA soldering on the NVidia Graphics chip. The symptoms of failed BGA soldering on the VGA chip are lines on the video while booting, with intermittent dots and change of shape, always in a vertical style pattern.

    Now I managed to fix the this with a hardware modification instead of refluxing the BGA which is a more complex operation by increasing the pressure of the heatsink on the GPU.
    What I did was unscrew the 6 screws holding the heatsink. With it removed you will notice 2 supports on the top that screw the heatsink on the NVidia chip, so these are not the 4 screws with springs holding on the CPU. The brass cyilinders in which the screws go in can be filed down 1mm until they are flush with the larger diameter part (so not all of it, just file it down to the larger part of teh cylinder). You can do this easily with a large metal file. Once this has been done remember to reapply silicon heatsink grease on the CPU: don't apply arctic silver as it conducts and if you exaggerate it will overflow onto the side components and short something on the CPU.
    When you screw the heatsink back on, be careful while you tighten the top screws: if you filed the 2 cilinders down correctly you should be ok. At first you can tighten them 50% of the way and check if your problem has gone. if it has, apply some hot glue to avoid it getting unscrewed.
    Good luck!
  2. raysfan81 macrumors 6502a


    Oct 6, 2009
    North Carolina
    That might work for a while, but like the iBook graphics card "fixes" it will fail again. The only way to fix it is to re-flow the solder.
  3. atod macrumors newbie

    Feb 15, 2011
    DaIceMan - I would try to email you from here, but I don't know how.

    Did your iMac display the display issues before (I'm assuming yes)? Is this fix working alone without smcFanControl? Have you seen any display problems since performing this fix?

  4. rtrt macrumors 6502a

    Jan 19, 2008
    smc fan control only works with intel afaik

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