24" iMac Screen Glitches - Suggestions?

Discussion in 'iMac' started by Nym, Feb 2, 2009.

  1. Nym macrumors 6502a


    Oct 4, 2006
    Porto, Portugal
    Hi everyone!

    I've been having some graphic glitches on my 24" iMac (late 06, 2.16 C2D, 1GB RAM, NVIDIA 7300 GT 128 MB) and I'm really starting to worry.

    I think that the problem started to happen around the time I installed Leopard on it. I even upgraded to 3GB RAM to make sure that that wasn't the problem but no go, I'm still getting the occasional glitch (well, sometimes it's more than occasional.

    I'm afraid that my GPU is toast because if that's the case am I suppose to just throw the iMac in the trash? Keep in mind I live in Portugal where there is still no official Apple Store and my 2 year waranty has just ended in October 08.

    What are my possibilities? I already had to replace the Superdrive (stopped working) and the hard drive (needle was clicking constantly on the HD) but it was all under warranty.

    I'm afraid this time it's "bye bye" to a 2000€ computer that is just 2 years and 3 months old.

    Here's a screenie so you can see what it's all about, this screenshot was taken just 15 minutes ago.

    Thanks in advance for any help.

    Attached Files:

  2. axphin macrumors newbie

    Feb 25, 2009
    More 24" iMac Glitches

    We have a few of these same spec iMacs around and we've seen this same video problem on about 2 or 3 of them. I just did a fresh install of 10.5.6 on one of them today and have been having major problems with video glitches, etc. I can even see the video glitches over Apple Remote Desktop, so it must be a software issue and not hardware. I also tried reinstalling the 10.5.6 combo updater but that didn't help.

    I noticed that there are two EFI/BootROM updates in SW Update. 1.1 and 1.2.

    1.1 Updates to IM61.0093.B01
    1.2 Updates to IM61.0093.B07
    My BootROM version is currently:

    I went ahead and installed both EFI updates, so we'll see how it goes (now running B07).

  3. harry454 macrumors 6502

    Sep 13, 2007
    yeah that is odd, usually stuff like that is about to die video, but it seems like software driver problem
  4. axphin macrumors newbie

    Feb 25, 2009
    No luck. Still reporting glitches after updating the firmware. I will try looking up the service manual since I am an Apple Certified Technician and have access to that data.
  5. petteri macrumors member

    Aug 4, 2006
    in the bin

    I had the exact same problems. I took the computer the Apple Store. I'm now waiting for the new mac mini.... :mad:
  6. djc6 macrumors 6502

    Aug 11, 2007
    Cleveland, OH
  7. axphin macrumors newbie

    Feb 25, 2009
    Interesting thread, but I think my situation is different. The glitches show up at the login window and also for different users logged into the machine whether or not they have a lot of icons. We do have some Mid 2007 iMacs that do exhibit the glitches in that other thread. But these glitches are from the 2006 iMac 24" (the white one).

    I read the service manual and it doesn't mention troubleshooting any display glitches but it does have some steps for troubleshooting the display if it is off or tinted another color. Zap PRAM, connect an external monitor with the mini-DVI port, check the internal video cable connections, replace the internal video cables and lastly to replace the lcd panel itself. I also read about replacing the video card itself which is not a quick repair. I may not have much of a choice but to try replacing some of the hardware.

    FYI, one of the iMacs that has the glitch problem DOES have an external monitor connected via mini-DVI and the problem exists on the external monitor as well.
  8. dtzens macrumors newbie

    Feb 25, 2009
    The problem I am having is very similar to this except a little more extreme.
    What happens to our iMacs is that yellow and green (mostly) triangles and polygons appear when there is moving images on the screen. It usually begins happening when zooming or panning in CAD programs like VectorWorks or SketchUp and then affects all other programs until restarted at least once. The occurrences are very intermittent. It is now happening on 3 of our 5 iMacs. The first occurrence was on a 24" Aluminum Intel iMac purchased in Aug 2007 running Tiger. Updating Tiger and Firmware didn't fix it.
    Below are some images of what happens:
    Also some movies taken with my phone of it happening on one of the newest 20" iMacs can be downloaded. Right-Click on the links and save them as .3GP, since I don't know how to embed a 3GP movie.
    20" Graphics Glitch 01 20" Graphics Glitch 02
    Here is a breakdown of the affected machines all are Intel Core 2 Duo:
    1) 24" Alum. | ATI Radeon HD 2600 Pro | purchased Aug 2007 | 1st glitches Feb 2008 on Tiger | glitches still on up-to-date Leopard but Firmware would not install.
    2) 20" Alum. | ATI Radeon HD 2400 XT | purchased Jan 2009 | 1st glitches Jan 2009 on up-to-date Leopard & Firmware
    3) 20" White | ATI Radeon X1600 | purchased July 2007 | 1st glitches Feb 2009 on up-to-date Leopard, no glitches running Tiger

    Any one have any ideas. Apple had me run the "Extensive" Hardware Test on the new 20". No problems reported, surprise. So I ran it on looping mode for about 16 hours and still no problems found.
    Here is the System Info from the newest 20":
    Hardware Overview:
    Model Name: iMac
    Model Identifier: iMac8,1
    Processor Name: Intel Core 2 Duo
    Processor Speed: 2.4 GHz
    Number Of Processors: 1
    Total Number Of Cores: 2
    L2 Cache: 6 MB
    Memory: 4 GB
    Bus Speed: 1.07 GHz
    Boot ROM Version: IM81.00C1.B00
    SMC Version: 1.29f1
    ATI Radeon HD 2400 XT:
    Chipset Model: ATI Radeon HD 2400
    Type: Display
    Bus: PCIe
    PCIe Lane Width: x16
    VRAM (Total): 128 MB
    Vendor: ATI (0x1002)
    Device ID: 0x94c8
    Revision ID: 0x0000
    ROM Revision: 113-B2250H-259
    EFI Driver Version: 01.00.259
    Resolution: 1680 x 1050
    Depth: 32-bit Color
    Core Image: Hardware Accelerated
    Main Display: Yes
    Mirror: Off
    Online: Yes
    Quartz Extreme: Supported
    Built-In: Yes
    Display Connector:
    Status: No display connected

    We have two more 20" iMacs that we bought in Jan 2009 (the same time as the other 20"). These have so far not experienced any glitches. I would return the latest one if I knew it wouldn't happen to it replacement.

    Someone Please Help!
  9. rfrankl macrumors 6502

    Apr 15, 2006
    I started having similar type glitches on my late 06 24" iMac. If I turned up the fan speeds, they didn't happen as often. Slowly though they started to happen again, and since I had AppleCare, I said why keep waiting and just get it fixed. It was the video card, and they just replaced it last week and I am good as new. On the 24" models, the video card is not one with the logic board.
  10. lorem3k macrumors newbie

    Feb 25, 2009
  11. dtzens macrumors newbie

    Feb 25, 2009

    How do you turn up the fan speeds on the iMac? That seems to be worth a try for the two iMacs that are no longer under warranty.
    Also sounds like it would be a good idea to get the AppleCare on the two 20" iMacs that this hasn't happened to yet incase it does happen 11 months from now.
  12. PeterQC macrumors 6502a


    Jun 30, 2008
    I don't think it's software. Whatever you will do would most likely not help. I think your Graphic card is shot. You'll need a new logic board for that, which unfortunately cost a fortune.

    Are you sure your 2 years warranty is over? Was it over Apple care? if yes then you have 3 years of coverage, not just 2 (from the day your purchased the computer). If you're still under Apple Care, I believe you can call Apple Brazil to get a box to send them the defected computer so they can repair it, At least it's how it work in US and Canada.
  13. rfrankl macrumors 6502

    Apr 15, 2006
    I turn up the fan speeds using SMC Fan Control. Free program you can find easily.
  14. axphin macrumors newbie

    Feb 25, 2009
    I ordered a new video card and cables for the glitchy 24" Late 2006 (white) iMac.
    Will post back with results.

  15. dtzens macrumors newbie

    Feb 25, 2009

    Where did you order the new Graphics Card? Is it extraordinarily expensive? Man with all the display problems I am reading about in forums, I really wish we would have built a couple of Hackintoshs with some decent Samsung LCDs. We would have been ahead several hundred dollars with better hardware just not as pretty.


  16. axphin macrumors newbie

    Feb 25, 2009
    I ordered the part as a Repair from Apple Global Service Exchange. Like I mentioned before I am an Apple Certified Mac Tech, so I can do qualified repairs on Apple hardware.

    For more info:

    And the part price was a little over $100 I think.
  17. axphin macrumors newbie

    Feb 25, 2009
    Repair complete. I replaced the video card and so far so good. No glitches after running for about 24 hours. If it holds for a few more days I'll go ahead and order another new video card for the other glitchy 24" iMac (Late 2006) that is giving us trouble.

    FYI, I replaced the LVDS cable as well just because it was so cheap. I didn't have time to see if just the LVDS cable fixed the issue, but I really doubt it could be the problem here. Next time I'll just replace the video card.

  18. axphin macrumors newbie

    Feb 25, 2009
    I finished the repair of the 2nd 24" Late 2006 (White) iMac and it seems to have fixed the problem again. I replaced the video card and all is well. I did notice a small difference between the replacement video card and the bad video card (on both repairs). It looks like they replaced a capacitor or a chip (not sure what it is) on the replacement video card. The sticker placed on it has a number that is one higher than the bad board. The bad board is 3021 and the good board is 3022. And the newer chip is about twice as big as the bad one. Other than that, the video cards look identical. And the newer working cards aren't brand new. They've obviously been used before.
  19. OldCorpse macrumors 65816


    Dec 7, 2005
    compost heap
    This is a depressing and discouraging thread. I was in the market for a 24 iMac, but now I'm gonna hold off till the middle of next year. How can Apple let QC get so bad?
  20. jmpage2 macrumors 68030


    Sep 14, 2007
    The real problem is Apple using crappy Nvidia GPUs on these machines, which is one reason many are waiting on the iMac with ATI graphics even if it means waiting another month or longer!
  21. axphin macrumors newbie

    Feb 25, 2009
    Well, keep in mind that the iMacs that I repaired were the white (Late 2006) models. Those models along with their video cards are a few generations behind the current models. My main work computer is a 24" Mid 2007 Aluminum iMac and I've had no problems at all. And I've had ATI cards go bad in my PC so nobody is immune.
  22. axphin macrumors newbie

    Feb 25, 2009
    Speaking of other video card repairs, I have to repair another ATI X1900 XT in a MacPro. This is the second one I've had to do. The ATI cards show glitches across the screen similar to the iMac problem, but not nearly as bad as the aluminum imac glitches in the post above.
  23. rmvz3 macrumors newbie

    Jun 28, 2009
    Hi all.

    I'm having the same problem with my white late 2006 iMac 24 2.16 C2D.

    I've noticed that almost everytime I can revert the glitches using SMC Fan Control (otherwise it freezes eventually) so it's clearly a hardware problem. I REALLY would like to buy the graphic card but I have no clue of where can I do it.

    Would you please tell me a place to buy the card?. A name to seach?. Anything will be very usefull for me.

  24. turqmelon macrumors newbie

    Jun 28, 2009
    Did any of you try calling an apple support representative?
  25. auto123 macrumors member


    Jun 25, 2008
    maybe this is a bad time but a pc wouldn't have this problem

    have you tried doing a clean install of os x?

    have you tried linux (or another OS)? (to see if you still get graphics errors)

    have you tested the memory?

    just a few things to check before putting that thing in the trash,

    also if you can remove the mother board I heard there are a few fixes for dead or dying mother boards. google (or bing) mother board revival or something of the sort


    heard it worked for some faulty laptop motherboards

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