iMac 27" (Late 2012) Cracking Sound

Discussion in 'iMac' started by FlagellumDei, Mar 18, 2013.

  1. macrumors member

    Mar 20, 2009
    I finally got my 27" iMac (Late 2012, 3.2GHz, 8GB, 1TB, GTX 675MX) a few days ago (last thursday), and yesterday I noticed a crackling sound from the lower left corner, near the power on button (somewhere between the HDD and the bottom edge of the Mac). This crackling sound starts right after the boot logo shows up and continues to do so regularly every 1-2 minutes no matter what I do on the Mac.

    I thought that this is maybe the left speaker (?) but the crackling sound is still present if I plug in a headphone.

    I think it's not the hard drive which is the Wester Digital 1TB one, because HDD failure clicking sound is familiaar to me.

    So I though it could be the power supply? If I'm seeing correctly on the teardown pictures, the power supply is located somewhere in the lower-left part of the 27" iMac?

    I recorded the crackling sound with my iPhone:

    You can here it approximately after 5 seconds.

    I run Apple Hardware Test and no problems were found.

    What do you guys think?
  2. macrumors 68000

    Dec 13, 2012
    I had the gurgle noise when I got my late 09 27", took it back to the re seller they ran tests and came up with nothing. 3 years on the HD was replaced by Apples recall programme and now it is silent.

    If I had of bought it from Apple and could of swapped it I would of. Your call.
  3. macrumors newbie

    Mar 18, 2013
  4. thread starter macrumors member

    Mar 20, 2009
    I read through the thread, and it's the same problem indeed. I can hear that sound even when it's turned off for some time after! I think it's probably the adhesive tape. And I can reproduce that sound by pressing the lower left corner of the screen.
  5. macrumors newbie

    Mar 18, 2013
    Don't hesitat to replace it... It's already my 4th replacement... I'm waiting for the new one on next wednesday...
    SOrry for my enlgish i'm french LoL
    But how can an adhesive tape reproduce that kind of noise ???
  6. thread starter macrumors member

    Mar 20, 2009
    I think when it warms up or cools down it makes that kind of sound. This could explain why I'm hearing that sound even when the Mac is turned off (and plugged off!) for 15-30 minutes after I shut it down. And the adhesive tape is located somewhere there where the sound is coming from.
  7. macrumors 68040

    Jan 8, 2013
    It is normal. Even when you start the AC of the car when outside is over 30C at the beginning the same noise comes out from the dash
  8. macrumors 6502

    Aug 7, 2007
    It's normal! it's the squirrels eating before they start turning the fan.
  9. macrumors newbie

    Mar 18, 2013
    Ok... it's normal according to you. And what do you suggest to fix it ?
  10. thread starter macrumors member

    Mar 20, 2009
    It would be normal if this sound came only when warming up or cooling down, but it's crackling all the time when the Mac is on.
  11. macrumors newbie

    Mar 18, 2013
    totally agree! It is not normal ! As soon as i receive the new one i'll post on this topic.
  12. thread starter macrumors member

    Mar 20, 2009
    Your other iMacs you replaced had the same crackling problem or there were some other problems?
  13. macrumors newbie

    Mar 18, 2013
    Yes, they had exactly the same crackeling problem, but the last one had crackeling problem and ratling noise too ....
  14. macrumors 6502

    Mar 15, 2008
    I had the same issue - it latest 4 weeks or so.
    I'm fairly sure its the tape securing the screen to the aluminium - guessing it needs a few heat cycles to cure.
  15. thread starter macrumors member

    Mar 20, 2009
    After 4 weeks it stopped to make this sound?

    Otherwise the machine is a powerful beast! It's much faster than my old Unibody MBP (Late 2008).
  16. macrumors newbie

    Mar 18, 2013
    Good remark !! I didn't thought about that, but it could be the solution.
    Of course I didn't wait for 4 weeks because we have just 2 weeks to replace it for a new one !!

    So the next one i will wait at least 4 weeks. Maybe do you have a solution to reduice this delays of 4 weeks ?? :) I have to use it all the time ?? night and day ?
  17. macrumors newbie

    Apr 4, 2013
    Same problem

    No additional insights other than that I noticed it happening about a month ago, didn't see so many forum posts about it, called Apple and they weren't aware of any known issues. Now at least I know I'm not crazy. It's not worth me returning it, though the tech did say that for such a big machine, they would probably be able to send someone to my house to take a look at it. That's probably not an option for everyone, depending on where they live. I didn't notice it happening within the first few weeks of owning the machine. It definitely is mostly happening after powering on or waking up from sleep, does it regularly for 5-10 minutes and then seems to go away (or maybe is so intermittent that I don't notice). I think it may indeed be this adhesive tape issue because I can also recreate the sound by pressing on the iMac itself with my fingers. It's annoying, but I would be relieved to know that it's a physical issue like that and not mechanical or electrical.
  18. macrumors 6502


    Jul 8, 2011
    I have the same issue... bottom left corner. It seems like it's related to the screen as opposed to the HD as I can almost trigger the noise by changing the brightness. Also, if I shut the iMac down I sometimes hear it a few times in a row, despite the iMac being turned off. The idea of it being some adhesive/tape could make sense but I've had mine for just over 2 weeks now and used it quite a lot.

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