27" iMac whines when brightness turned down

Discussion in 'iMac' started by peteullo, Apr 27, 2010.

  1. peteullo macrumors regular

    peteullo

    Joined:
    Dec 13, 2009
    Location:
    Scranton, PA
    #1
    I have a 27" iMac w/ i7 that has been driving me nuts lately.. When you turn down the brightness on the screen the unit begins to let off a high pitch whining noise. On full brightness it makes no noise at all but soon as a I lower the brightness one click the whining starts. I also noticed that when I turn down the brightness all the way to 0 that the noise completely stops.

    I have another (3)27" iMac's w/ i5 that don't seem to have these problems. I was wondering if this has happened to anyone else?

    I placed a call into a local authorized service center so I have already begun the process of hopefully getting this repaired.
     
  2. swee5420 macrumors member

    Joined:
    Feb 10, 2010
    #2
    I have been through 5 replacements with different issue, and all 5 have the high pitch and buzzing issue, when increasing or decreasing the brightness. I don't think there is a solution for that yet, just like the yellow tinge.
     
  3. peteullo thread starter macrumors regular

    peteullo

    Joined:
    Dec 13, 2009
    Location:
    Scranton, PA
    #3
    Like I was saying.. I have 3 other iMacs around the house without that issue but for some reason mine is sooo bad that I can hear it from across the room as soon as it kicks on.

    I dropped off the computer at an Apple Store rather than the authorized center. I was told they ordered a Backlight board and I think a new screen as well. I also mentioned to them from what I read on Apples forums that a few people reported power supplies fixing their problem and they added that to the parts request list.

    I should have the computer back in a few days so I will update then.
     
  4. swee5420 macrumors member

    Joined:
    Feb 10, 2010
    #4
    Please remember to report to this thread if the issue is fixed
     
  5. CubeHacker macrumors 65816

    CubeHacker

    Joined:
    Apr 22, 2003
    #5
    Sounds like inverter whine to me. The replaced backlight board should fix it, hopefully.
     
  6. IndustrialSpace macrumors 6502a

    Joined:
    Dec 31, 2009
    Location:
    somewhere
    #6
    Bump...
    I'd like to know what comes of this too.
     
  7. WilliamG macrumors G3

    Joined:
    Mar 29, 2008
    Location:
    Seattle
    #7
    My i7 does not have this issue. However, all of my Apple 23" Cinema Displays did. At max brightness, there was no sound from the screen, but at anything less than full brightness, there was a sound emitting from the screen that would drive me nuts.
     
  8. adammjenkins macrumors member

    Joined:
    Dec 15, 2009
    Location:
    West Virginia
    #8
    I am on my third 27" iMac due to screen brightness noise issues. The issue normally occurs when the computer is running hotter (ex. ripping a dvd in Handbrake which uses all 4 cores). At most points <50% brightness, it is pretty much silent, but anything above 50% brightness, I begin to hear high pitched, almost dog-whistle noises combined with a buzzing noise that almost sounds as if there is a fly trapped in the upper left corner. I have taken audio samples and they've been forwarded to the engineering department through a senior adviser on the previous 2 iMacs. The first one that I received back in December had the exact opposite issue... at <50% brightness, it would make the fly buzzing sound along with the high pitched whistle noise. The last two have been at brightness above 50%. Apple Care was suspecting an environmental issue that was causing the noises... something like dirty electricity, causing the noises. I am just worried about long-term hardware issues due to misappropriated electricity.

    If anyone gets any answers on this, please post back here. I'll try to do the same once Apple Care gets back with me. At this point, I am considering opting for a refund and holding out until the next refresh comes. I'm just not sure that a 4th replacement is going to solve the problem.
     
  9. MH01 Suspended

    MH01

    Joined:
    Feb 11, 2008
    #9
    same issue here.

    I have the same issue with my Imac, though This was never a problem, When i got my imac (4th one after replacements) everything was fine. I am not sure if the last firmware update did not bring this issue out. Looks like I will be dragging the damn thing into the apple store soon, wish it was not so heavy.
     
  10. andreviegas macrumors newbie

    Joined:
    Jan 11, 2010
    #10
    Now that I receive an imac with almost no yelow tinge, I have this problem also, it seems like a high-pitched noise coming from the left corner.
    I can´t believe that they solve one problem and then create other.
     
  11. peteullo thread starter macrumors regular

    peteullo

    Joined:
    Dec 13, 2009
    Location:
    Scranton, PA
    #11
    Just got the iMac back on Tuesday. Apple replaced the LED Backlight board and problems seems to be cured. I hope this helps anyone who may have these issues.
     
  12. andreviegas macrumors newbie

    Joined:
    Jan 11, 2010
    #12
    Mine is going monday to repair, when I have it, I will post what they changed.
     
  13. EnterTheSwamp macrumors member

    Joined:
    Jun 29, 2010

Share This Page