Bizarre problems with my iMac

Discussion in 'iMac' started by garirry, Apr 16, 2015.

  1. garirry, Apr 16, 2015
    Last edited: Apr 16, 2015

    garirry macrumors 68000

    garirry

    Joined:
    Apr 27, 2013
    Location:
    Canada is my city
    #1
    Ugh, I'm really annoyed again. I can't use my computer for a month before something happens to it again. Basically, I changed the hard drive one month ago because the previous one was going crazy and my system crashed every five minutes. I did a CCC backup, and because of that the recovery partition did not copy. Anyway, today, I turned on my computer from its turned off screen and I started using it but my cursor was a glitchy 64x64 square. I don't have a pic because I am too much of an idiot to take the picture prior to restarting the computer. Following that, I launched an app in Parallels and my system immediately froze after. Nothing would react at all. So, I force rebooted my computer and the OS wouldn't boot. After the loading circle disappeared, the glitchy cursor appeared again and although I could move it freely, the system wouldn't load any further. I restarted a few times, and every time, it got stuck on the "post-boot" screen, except there was no cursor at all. I even waited a few minutes to see if it would eventually boot, but it was useless.

    I... don't know what to say. I'll post a pic of the glitchy cursor if it ever reappears again. I would have just connected my Macbook's hard drive to the computer to reinstall Mavericks with the recovery partition, except the fact that it'll take a very long while especially if there's something major in the partition and I'll have to do a time machine restore. Any thoughts on this? I had a lot of problems with my iMac (I'm already trying to save for a brand new PC) including the ready-to-die hard drive and the occasional graphic card problems. I appreciate all help in advance. :confused:

    EDIT: Link to pictures: http://imgur.com/A5RR7ek,Bz6irtr Navigating on the phone is a pain. Also, my computer now refuses to boot from my laptop's hard drive, even though it worked before (same problem, stuck on blue screen of booting). ALSO, after waiting ten minutes, my computer showed this beauty: http://imgur.com/ICglRK4
     
  2. garirry thread starter macrumors 68000

    garirry

    Joined:
    Apr 27, 2013
    Location:
    Canada is my city
    #2
    Oh great. I can't even boot onto the SL disc. I have a bad feeling that my iMac is dying. I need it for at least a few more months before I save up for a new computer.
     
  3. garirry thread starter macrumors 68000

    garirry

    Joined:
    Apr 27, 2013
    Location:
    Canada is my city
    #3
    Umm, anyone? Apparently, the computer works fine on safe mode, reset PRAM, SMC, only safe mode apparently works. The cursor is still glitchy though.
     
  4. Dopeyman macrumors 6502a

    Joined:
    Sep 5, 2005
    Location:
    Los Angeles!
    #4
    I would suggest backing everything up and start from scratch. Format the drive and reinstall your OS. And manually copy over the stuff that you need onto your fresh drive.. Don't use the time machine backup or CCC backup... You might transfer over a bad system file or whatever it is that's messing up your computer back on...
     
  5. garirry thread starter macrumors 68000

    garirry

    Joined:
    Apr 27, 2013
    Location:
    Canada is my city
    #5
    Thank you for your answer, but it's not it. I can't boot onto ANY operating system, including my laptop's hard drive (which worked before), nor my Snow Leopard disc (worked multiple times before). All freeze on startup and then sometimes show graphical glitches, including always showing the glitchy cursor. Luckily, one of my friend came by (who is much more advanced in computers than me) and he tried to view the Command+V text but it disappears as soon as the computer freezes. Right now, I'm waiting for it to finish the Apple Hardware Test. Oh BTW, in case someone's interested for the specs, it's a late 2009 21.5" iMac with a 1TB brand new hard drive, 12GB of memory, ATI Radeon 4670 graphic card (or something like that, and that's it I think? I dunno, my memory refuses to obey right now.

    Either way, it's definitely not a bad installation of OS X, it's not memory because I tested each one individually in each slot, and it's not hard drive because 1) it's new 2) Disk Utility said it's fine. Safe mode boots fine though but still shows the glitchy cursor. I appreciate all help though.
     
  6. redheeler macrumors 603

    redheeler

    Joined:
    Oct 17, 2014
    #6
    It might help to pinpoint the problem if you hold down Command-V to boot into verbose mode and see where it breaks, although to me it sounds like a GPU related issue.
     
  7. garirry thread starter macrumors 68000

    garirry

    Joined:
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    Location:
    Canada is my city
    #7
    I tried, it went fully fine at first, but when the break happened, the text on the screen disappeared and there was nothing written anymore, so I couldn't see what was the problem. I may try again though, but first I will have to wait until the AHT finishes, it may take two more hours.
     
  8. redheeler macrumors 603

    redheeler

    Joined:
    Oct 17, 2014
    #8
    My bad, I misread where you had already mentioned that in your post. I still think it's a GPU issue.
     
  9. garirry thread starter macrumors 68000

    garirry

    Joined:
    Apr 27, 2013
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    #9
    Yeah, I suspect a GPU issue too. My question is: Is it possible to somehow deactivate the GPU and use the main processor as the graphics card? Not sure if this is possible. I ran AHT, the short test said there was no issues, the long test freezes after a certain portion of the test.
     
  10. garirry thread starter macrumors 68000

    garirry

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    Canada is my city
    #10
    Has anyone any other ideas? I can't just keep using my computer in safe mode (massive lag, no sound, half the programs don't even work), but I have noticed some graphical hiccups occasionally, not sure if it's because I'm running it in safe mode. I'll try reinstalling the system again, maybe it'll work, who knows. I tried Command-V again and the message disappears right before the crash.
     
  11. garirry thread starter macrumors 68000

    garirry

    Joined:
    Apr 27, 2013
    Location:
    Canada is my city
    #11
    I apologize for constantly double/triple-posting, but this situation is really making me nervous and I need help.

    I got the idea that maybe it is possible to under-clock the GPU in my Mac because of how convinced I am that it's a graphics card issue. The glitchy cursor appears even in safe mode on Snow Leopard, but if I launch the regular version it will fail to initialize the whole UI and the system will look glitched. I need a program that can under-clock the card in the whole computer, not just the OS, and that works on Mac, I can't access Windows on my iMac, I don't have Boot Camp and I certainly will not install it in safe mode. Any advice? Someone please reply, I'm really really worried. :(
     
  12. garirry thread starter macrumors 68000

    garirry

    Joined:
    Apr 27, 2013
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    Canada is my city
    #12
    Okay, sorry for posting so much, but has anyone any ideas of what I can do? I'd rather not spend 200+ dollars on a new graphics card, and I feel like underclocking may solve the problems. Yes, I'm about to buy a new PC because my Mac is still quite old, but I'd rather have the computer in my collection rather than in the trash. :confused:
     
  13. macthefork macrumors 6502

    Joined:
    Feb 2, 2013
    #13
    It could very well be a Graphics card issue if you are using the ATI Radeon 4670 Graphics card.

    Apple has (had) a free repair program out there for this issue.

    If you do suspect you have that video card in your iMac, I'd call Apple and see what they can do for you. It wouldn't cost anything to try.
     
  14. MacTech68 macrumors 68000

    MacTech68

    Joined:
    Mar 16, 2008
    Location:
    Australia, Perth
    #14
    I have a much earlier iMac Late 2006 which began suffering video artifacts/glitches a few years ago. I also found safe mode worked. Since the video card in my model is integrated onto the motherboard, I discovered that moving the ATI kernel extensions out made the machine work, and it has done ever since.

    Playing back video is terrible, since video acceleration is disabled, but the machine is usable.

    Depending on what is wrong with your video card, YMMV.

    Booting into safe mode, delve into /System/Library/Extensions/ and look for AMD4600Controller.kext and drag it out to the desktop. You may need to copy them to the desktop and then delete the originals (using an administrator password) or better yet, use terminal to move them (safer).

    Code:
    sudo mv /System/Library/Extensions/AMD4600Controller.kext /Users/YOURUSERNAME/Desktop/
    
    If that doesn't allow booting normally, try removing all the AMD*****.kext and ATI******.kext drivers.

    The above assumes you DO have the ATI Radeon HD 4670 GPU.

    I also use "SMCFanControl" to crank up the fan speeds, it may help, but disabling the GPU acceleration kexts should work for now. Not sure of it's compatibility with Mavericks.

    With all the crashes you've most likely experienced, verifying the hard drive to ensure it's directory structure is intact is a must.
     
  15. garirry thread starter macrumors 68000

    garirry

    Joined:
    Apr 27, 2013
    Location:
    Canada is my city
    #15
    Holy Mac, it actually works! Thank you so much! :D It now boots into OS X without safe mode after I deleted all the .kext files you mentioned. Deleting only the one you recommended wouldn't let me boot still, but the cursor was no longer glitchy in safe mode (previously it was). However, I don't think I'll be able to use the system in this state. All graphical glitches that were present in Safe Mode are still there, and Windows 7 (Parallels) doesn't show Aero mode and not a single game plays on it. One thing I want to do is try to underclock the graphics card (the card itself, not system-only or else it probably won't work). I could try and install Windows 7 on Boot Camp, that might work but I don't know any software or such that would allow me to do this. Thanks again.
     
  16. idoccurt macrumors regular

    Joined:
    Aug 25, 2006
    #16

    Mine just turns black from time to time..software
     
  17. garirry thread starter macrumors 68000

    garirry

    Joined:
    Apr 27, 2013
    Location:
    Canada is my city
    #17
    *BUMP*

    A bit of an update happened. I booted my iMac after quite some time and decided to perform an update because I noticed that iTunes' icon was the old one. After it, suddenly the graphics became much smoother and everything was all shiny and stuff, and barely any lag was present. I apparently lost my common sense to realize that an update will most likely replace the files that are missing, and going into the extensions folder, they came back!

    So what it means is that either something weird happened with my computer and it magically fixed itself (although I doubt it because ML's installer showed me the glitchy cursor when I needed to restore from a backup) or that update actually fixed those issues. Wierd, huh. I'll have to do some extensive testing, and see whether everything has been fixed or if it's just temporary. Regardless, I am putting my plan of reflowing the GPU on hold until it breaks again since I do not want to risk damaging my computer.

    Also, quick question. After changing the hard drive, the backlight seems to make a small power-supply style beep whenever the brightness is set too high. Any ideas?
     
  18. MacTech68 macrumors 68000

    MacTech68

    Joined:
    Mar 16, 2008
    Location:
    Australia, Perth
    #18
    There's nothing worse than a fault that appears to fix itself - though opinions vary. ;)

    Does the backlight momentarily or continuously beep, or is is a long squeal ?

    I DO know some hard drives may beep momentarily (usually once) when they first try to spin up.
     
  19. garirry thread starter macrumors 68000

    garirry

    Joined:
    Apr 27, 2013
    Location:
    Canada is my city
    #19
    That's true, it's annoying because it is still probably broken yet I will be unable to do anything like a reflow since it's still useable.

    It's not a beeping, it's a permanent squeak, until the backlight level is lower. I noticed however that when I upgraded the computer, I accidentally damaged the 4-pin little wire in the upper-left corner I believe. I'm not sure whether that has anything to do with it.

    It's certainly not the hard drive. Reducing the backlight stops it, and both hard drives I used in it caused the exact same thing. This computer has quite many problems I need to fix if I want to be able to use it again. :(
     
  20. MacTech68 macrumors 68000

    MacTech68

    Joined:
    Mar 16, 2008
    Location:
    Australia, Perth
    #20
    It's more than likely the small SMD transformers on the backlight Inverter PCB oscillating at a resonant high frequency. Resoldering each SMD transformer MIGHT fix it. You might want to check that the PCB isn't shorting on any shielding. Does the backlighting look uniform?
     

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