Previous 1 2 3 4 5 6 Next 115 Replies Latest reply: Oct 9, 2010 9:42 AM by Dave13 Go to original post
  • nintendew Level 1 (15 points)
    As a dissaffected iMac owner, I'm just going to briefly comment, so that Apple sees this thread.
  • Phil Gribbon Level 1 (5 points)
    Also affected by the above issue, nothing new to report. Apple aren't too speedy at addressing some issues, are they? Especially when they can hear the sound of tills ringing for replacement logic boards + graphics cards.

    smcFanControl seems to help, but the noise of the fans reminds me of my old 17" G5 iMac that had everybody on these forums complaining about the whining noise ("it's like an aircraft taking off!"). Maybe Apple went for the silent computer with a bit too much enthusiasm.
  • Luke Noel-Storr Level 1 (35 points)
    Well, fan control has solved this for me for a while, but it seems to be creeping back.

    Previously, I just had to ensure my temperature stayed below 40°C and all was fine; however, now the lines are starting to appear when my temperature is 35°C, and sometimes less, meaning I now have to have my fans spinning at quite a rate.

    I'm worried that if this continues to degrade, then the fan solution will cease to help.
  • Dylan Duverge Level 1 (5 points)
    I also have a late 2006 24" iMac and began having this problem about a half year ago. After reading some forums I installed SMCfancontrol which semed to help...also I noticed a lot of dust clogging the fan intake (or outflow...not sure which) and removed it. After a few days of my computer freezing constantly, often not even getting to the login screen, it just seemed to work my delight.

    Until now. For the past couple weeks my computer has not worked at all. I get many graphics corruptions (not so much the horizontal lines like the first time, but many colorful pixels that "dust" my screen, and sometimes moved around with the mouse). The only way I can actually start up at this point is in safe mode (and this works only 1 in 10 times). I cannot even start from the Leopard DVD. I took it into a apple authorize repair shop and they said it was a malfunctioning GPU, though they couldn't run diagnostics because nothing would boot from CD. I didn't buy apple care because my macs always just worked. So not happy right now =(.

    I'm curious if the people having problems have BootCamp installed, because each time I've had this problem start was when I was running windows a lot for various things. This past episode, the freezing, blue screen, graphics corruption etc started in full force as soon as I put windows vista to sleep. Is it possible to sele an iMac for parts, and does anyone know how much people could get for an iMac with a broken GPU?
  • Robert Cates Level 1 (25 points)
    Hi everyone. Sorry for the double post.

    Late 2006 20" with same problem as well as the psychedelic shapes problem. I'll have to try the SMCfancontrol suggestion and let you know what happens. BTW I do not have BootCamp installed on my machine.
  • MonkeySwitch Level 1 (0 points)
    The symptoms on my iMac were identical to all of the images here. I took my iMac to the Apple store (thankfully I had applecare) and they are currently replacing the logic board (because the graphics card is apart of it) as well as the hard drive (unrelated?)
  • sypark Level 2 (355 points)
    Same exact problem with my 20" iMac (early 2006). Took it into Apple and another retailer and was told by both that it was a hard drive problem. Got it replaced, with no results.

    Came upon this page and installed SMC fan control, raised it a bit and moved my iMac away from my multifunction printer which was spewing out hot air. Keeping the CPU temp down from low to mid 40s to the upper 30s seems to have done the trick!
  • Skripo Level 1 (0 points)
    I have the same issue, called Apple and no love. It especially ****** me off because after 27 years or so of PC use (yes I had the original IBM PC) I switched to Apple and have since rid my home of all pcs. I currently own 4 macs, 3 iPhones, 1 Airport extreme (which also has issues), 1 Airtunes and 4 ipods in my home alone. Please don't rob me.

    I have done a ton of research and my best GUESS is that it is the same problem as the Macbook G series had. The video and/or memory uses Ball Grid Array (BGA) solder pads to attach to the logic board. In the older series these solder points would fail with repeated heat cycles. I am guessing / hoping / praying that this the same issue.

    I have torn apart my 20" Intel Imac Core 2 Duo 2.16 GHZ QP63** and replaced the heat sink compound, to no avail. I will be bringing in the logic board to my friend who has specialized equipment for reflowing the solder. We may have to remove and reball or even replace the chip.

    Several places offer professional BGA reflow or repair services. Do a local search under BGA reball or rework and you should find a local place willing to do it for $50 to $60. It beats the **** out of paying for a new logic board. I will try to get this done next week and update this thread. If it does work, keep your bill because Apple will eventually "recognize" this problem and may refund the repair.
  • Skripo Level 1 (0 points)
    I forgot to add that SMC is a stop gap measure that may prevent further deterioration but in my case it just got worse. The machine now regularly locks up.
  • Plexus Level 2 (205 points)
    hi there. i have a white 17" 2006 imac (intel duo). i started having this video problem over a year ago and using smcfancontrol was able to determine, i felt, it was a video hardware problem. cranking the fans up would lower the temp and make my machine more stable. but over the last 8 months, the imac was hanging more and more and giving me more video problems no matter how high i turned up the fans.

    finally, it died. i let it cool to room temperature over night and tried to re-boot and it would get into the login part of the boot process and die with a lot of video corruption.

    i opened up the imac and vacuumed it out, looked for other problems and issues and found none. put it back together and tried again. same thing. dead.

    so i bought a new macbook pro.

    i too think this is a video hardware issue. i didnt have applecare so i figured there was no point in talking to apple about it. crapple, i mean.

    doesnt seem to be a solution to this problem, does there?
  • Luke Noel-Storr Level 1 (35 points)
    OK, it seems that this problem is definitely related to Quartz Extreme.

    If I fire up the Quartz Debug tool (/Developer/Applications/Performance Tools/Quartz Debug) and then disable Quartz Extreme from the Tools menu, then I don't get the lines, turn it on again, I get the lines.

    To try it for yourself, you firstly need the developer tools installed.

    Then, do something to fire up the temperature, such as converting a video file.

    Next, do some activity that causes the lines (I go to Safari and scroll up and down a page - which tends to leave horizontal lines all over the place).

    Then, disable Quartz Extreme, and repeat the above activity. If the results are the same for you, then no new lines should be generated, and the existing lines will go away.

    Now - does anyone know a way to permanently disable Quartz Extreme, so that I can give that a go?

    Edit: Oh, and I also really hate the Apple support website. I just want to find out what I need to do to get my mac fixed, and nowhere on the site seems to tell me this. Other people have reported getting their logic board replaced, and as I'm still covered for parts and labour I thought I'd try and get this done - but how???

    Message was edited by: Luke Noel-Storr
  • Luke Noel-Storr Level 1 (35 points)
    I still need smcFanControl on though, as otherwise the temperature hits 56°C, everything starts going very slowly, and then I'm hit with a GSOD.
  • SciFrog Level 1 (100 points)
    Same problem here on a 24'' iMac. Definitely heat related also as the computer runs Folding 24/7. At least winter is coming and temperatures will be dropping...
  • Frederic BOTTARO Level 2 (250 points)
    Hi everyone,

    The "horizontal lines" club can count me as one of it's members.
    What I will post here might sound irrational to everyone of you. And surely, some will laugh at me telling me I'm nuts. But I'll do it anyway.

    As anyone else here, I started having horizontal lines on my iMac display. It is a 20' white iMac, 250GB hard drive, 512Mb original RAM to which I added 1GB and running the ATI X1600 graphics board with 256MB VRAM (ROM version : 113-xxxxxx-139 running 01.00.139 EFI). I has a 2.16Ghz Intel Core2Duo processor and SN starts with CK641...

    There's a simple trick to get rid of them for a while : just change the colour depth from "Millions" to "Hundreds" and then back again to "Millions". The lines have gone. But of course, after a while, then show up again...

    But what really puzzles me is following. My Apple Wireless (Bluetooth keyboard) ran out of battery and of course, that was on a saturday in the early evening, so no replacement batteries to get before monday. Can't live without my computer for such a long time. So I dig my crap to get my old USB keyboard. Hooked it up and it was recognized without a problem. Everything went well, with no lines or mock ups.
    Then, on monday, I get the replacement batteries, reinstalled my Bluetooth keyboard... there go the lines again. My computer locked up several times... I got so angry that I took it out of it's furniture and throw it on my bed (yes, I can get mat at times...).
    So now what has happened ? The Bluetooth module seems to have been disconnected as I have no Bluetooth in my preference panels anymore. I haver econnacted my old USB keyboard and have now no problems at all since 72 hours (which was just not to be achieved before) even with intensive WoW playing !

    So here are my mad assumptions :
    - can it be that the Bluetooth module sits near the graphics card and causes it to heat too much ?
    - can it be that the Bluetooth emissions interfere in some way with the graphics card ?

    And my question : are you all using Bluetooth devices ? If so, can you try your iMac without running them ?

    Please don't be too hard on me for what may seem to be an irrational post and explanation.


  • Frederic BOTTARO Level 2 (250 points)
    Hi Luke,

    Quartz Extreme can be ratehr easily disabled, especially since you have installed the developer tools already.
    Go to the following folder :
    System -> Library - > FrameWorks -> ApplicationServices.framework -> Versions -> A -> Frameworks - > CoreGraphics.framework -> Versions -> A -> Resources
    In this folder, you will see a file called : "Configuration.plist".
    Drag it to your Desktop and control-click it. Choose "Open with..." and select "Property list editor".
    Click on the arrow in front of "GLCompositorConfiguration" and then select the "GLCompositorMinimumVRAM" line. Change the default value (typically : "16") to something higher than the VRAM size of your graphics card. To be on the safe side, I entered "512" as my video card has 256MB of VRAM.
    Close the file... of course saving the changes.
    And then replace the file in the System folder with the one you just edited.
    Restart your iMac and open the Dashboard. Drag any widget to it... and Voilà. No more Water effect, which means Quartz Extreme is disabled.


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