Buzzing Noise w/Keyboard Backlight

Discussion in 'MacBook Pro' started by w00t951, Feb 28, 2013.

  1. w00t951 macrumors 68000

    w00t951

    Joined:
    Jan 6, 2009
    Location:
    Pittsburgh, PA
    #1
    I just noticed that my Mac makes a buzzing noise due to EMI from PWM. Does anyone know how to fix this?

    Running the keyboard backlight at anything other than off/maximum triggers this buzzing.
     
  2. justperry macrumors G3

    justperry

    Joined:
    Aug 10, 2007
    Location:
    In the core of a black hole.
    #2
    The keyboard backlight needs little current for it to work, if you get the noise when the backlight is on something is amiss, reason is that the buzzing normally appears only when lots of current is needed.
    For instance, if you have a 100% load on the CPU, not for a small current from the keyboard backlight.
     
  3. w00t951 thread starter macrumors 68000

    w00t951

    Joined:
    Jan 6, 2009
    Location:
    Pittsburgh, PA
    #3
    No, I've pinned it on PWM used to control the keyboard brightness. I'm at idle, and buzzing is only audible when the keyboard brightness needs to be something other than 0% or 100%.

    My question is, is there a way to stop this buzzing? It's slowly driving me insane.
     
  4. justperry macrumors G3

    justperry

    Joined:
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    Location:
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    #4
    Only way is to service it, that is if it's still inside warranty.
     
  5. w00t951 thread starter macrumors 68000

    w00t951

    Joined:
    Jan 6, 2009
    Location:
    Pittsburgh, PA
    #5
    It's not, unfortunately. Whatever, it's unnoticeable under normal use. Thanks anyway.
     
  6. justperry macrumors G3

    justperry

    Joined:
    Aug 10, 2007
    Location:
    In the core of a black hole.
    #6
    Actually there might be another solution, many times it's the power board and if yours has a separate one it might help.
    Can't guarantee though.
     

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