Power Brick really hot and making noise

Discussion in 'MacBook Air' started by roccobladr, Aug 19, 2011.

  1. roccobladr macrumors 6502

    Joined:
    Jul 25, 2011
    #1
    So I'm sitting here browsing the web and my battery is almost dead so I plug in the power adapter. Everything is fine and it has been charging for a little while (at least a half hour) and I hear a noise. I thought it was my speakers or something, but I notice that its coming from the power brick which is sitting on the desk too.

    It is making a slight staticky sound and is pretty hot to the touch.

    Is this normal?
     
  2. MrCheeto macrumors 68030

    MrCheeto

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    Nov 2, 2008
    #2
    This is normal.
     
  3. MrCheeto macrumors 68030

    MrCheeto

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    Nov 2, 2008
    #4
    It is.
     
  4. Raptura macrumors 6502

    Raptura

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    Sep 6, 2008
    Location:
    Toronto, Canada / London, UK
    #5
    Hot to the touch? Sure. That's normal.

    Making noise? Mine's never done that.
     
  5. ZBoater macrumors G3

    ZBoater

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    Jul 2, 2007
    Location:
    Sunny Florida
    #6
    Mine hasn't done either. I must not be using it right... :rolleyes:
     
  6. IngerMan macrumors 6502a

    IngerMan

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    Feb 21, 2011
    Location:
    Michigan
    #7
    very warm but never noticed the noise. I have two, and one I use when I am on the couch and the outlet is only a little over 2 feet from me. So I am sure I would of noticed noise.
     
  7. MrCheeto macrumors 68030

    MrCheeto

    Joined:
    Nov 2, 2008
    #8
    The high-pitched whining? Yes that's entirely normal with some components, including most power supplies at given wattage and duration of power draw.

    Mine does it very very rarely, such as when my MacBook Pro is on very low battery.
     
  8. Big-TDI-Guy macrumors 68030

    Big-TDI-Guy

    Joined:
    Jan 11, 2007
    #9
    From Wikipedia:

    Acoustic Noise: Usually inaudible to most humans, unless they have a fan or are unloaded/malfunctioning, or use a switching frequency within the audio range, or the laminations of the coil vibrate at a subharmonic of the operating frequency. The operating frequency of an unloaded SMPS is sometimes in the audible human range, and may sound subjectively quite loud for people who have hyperacusis in the relevant frequency range.

    http://en.wikipedia.org/wiki/Switched-mode_power_supply

    (article on switching mode power supplies)

    As for the heat - if it's doing work (powering your computer AND charging the battery) heat generation is normal. If it's so hot you cannot touch it (over 150F) I'd have a little concern. But if it's hot enough to touch without burning, you're likely fine.
     
  9. MrCheeto macrumors 68030

    MrCheeto

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    Nov 2, 2008
    #10
    See? I just said that.
     
  10. Big-TDI-Guy macrumors 68030

    Big-TDI-Guy

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    Jan 11, 2007
    #11
    Well, I was going to say the same thing, but then realized people wouldn't believe it anyhow, so I decided to reduce the level of effort on my end, and just link to Wikipedia - so they can dispute with Wiki, should they not believe that. I didn't feel like proving myself today to people who wouldn't believe me anyhow... :confused:

    But yes, I agree with your post, and so does Wikipedia. ;)
     
  11. ZipZap macrumors 601

    Joined:
    Dec 14, 2007
    #12
    In 30 years I have never had any power adapter that emitted any noise.

    It is not normal.

    As for the temp...

    If you can hold it in your hand for a extended period your fine. If it too hot to hold there is something wrong.

    Depite any comments here to the contray, if its too hot to hold or noisy I would exchange it.
     
  12. geekygeek macrumors regular

    Joined:
    Jul 12, 2011
    #13
    My power brick doesn't get hot at all except when my air is low then it gets really hot. I can hold it but my friend throws it away. As for the whining, I don't hear anything but I remember my little brother's DS charger does that, and I can hear it all the way across the living room.
     
  13. roccobladr thread starter macrumors 6502

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    Jul 25, 2011
    #14
    it seems like it only makes the sound when it is charging
     
  14. ZBoater macrumors G3

    ZBoater

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    Jul 2, 2007
    Location:
    Sunny Florida
    #15
    +1 Whining power adapters are not normal. Not in my planet anyway... :cool:
     
  15. MrCheeto macrumors 68030

    MrCheeto

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    Nov 2, 2008
    #16
    Let's not forget that it's emitted at frequencies that only certain people can hear.

    Usually younger people :rolleyes:
     
  16. Big-TDI-Guy macrumors 68030

    Big-TDI-Guy

    Joined:
    Jan 11, 2007
    #17
    See Mr. Cheeto, see why I took the lazy way out. ;)

    Even if I was an engineer, and worked with switch-mode supplies every day, I don't reside on the same planet, so all credibility is lost.

    The fact that pulse-width-modulation, frequency and load factor transitions causing harmonics within the audible range are clearly explained with basic electronics theory - we're on the internet. (so we lose)

    You did try, though. Kudos for that. :D

    Edit: P.S. Switch mode supplies have not been common for the past 30 years, especially when it comes to household power adapters, and what have you. Notice how light power adapters have gotten in the past decade or so? That's because they no longer use the same components as those of yesteryear.
     
  17. ZBoater macrumors G3

    ZBoater

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    Jul 2, 2007
    Location:
    Sunny Florida
    #18
    Well, at 42 I am not exactly a spring chicken but my hearing is pretty good. And I am not hearing any humming, noises, or whining out of any of my power adapters.

    I did hear it once on an adapter a while ago, right before it smoked...
     
  18. IngerMan macrumors 6502a

    IngerMan

    Joined:
    Feb 21, 2011
    Location:
    Michigan
    #19
    The noise would bother me. I know a guy that had his surge protector strip start on fire. Luckily it was while he was home and no real damage done. This was about 20 years ago, but I will never forget it.

    I would not risk the noise and take it back. Or at least unplug it before yo go to bed :eek:
     
  19. Gemütlichkeit macrumors 65816

    Gemütlichkeit

    Joined:
    Nov 17, 2010
    #20
    I made a similar thread about how hot the brick got. Everyone said it was normal.

    My 80w MBP brick never got THIS hot.
     
  20. Cynicalone macrumors 68040

    Cynicalone

    Joined:
    Jul 9, 2008
    Location:
    Okie land
    #21
    Apple power bricks get damn hot. iPads, iPhones, and MacBooks.

    But if it was making noise that would worry me. Last time I heard noise from a power brick was right before it smoked. Kinda of a high pitched sizzling sound, melted plastic and then smoke.
     
  21. ZBoater macrumors G3

    ZBoater

    Joined:
    Jul 2, 2007
    Location:
    Sunny Florida
    #22
    Not everyone. ;) Us old folk apparently think this is not normal because back when we were young the power adapters on the Mayflower made noise when they were going bad...

    ----------

    According to the younger crowd that's just how they work these days. However, if it's all the same to everyone, I'm not sitting next to a whining hot power supply. :D
     
  22. EchoPure macrumors member

    Joined:
    Jul 20, 2011
    #23
    I can hear noise when charing from my power brick and the magnetic end. I couldn't hear it before :(
     
  23. yusukeaoki macrumors 68030

    yusukeaoki

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    Mar 22, 2011
    Location:
    Tokyo, Japan
    #24
    Hot yeah also for my 85 watt magsafe for my MBP.
    Making noises? no never done that
     
  24. Azathoth macrumors 6502a

    Joined:
    Sep 16, 2009
    #25
    In the morning.

    Hmmf, so much for the Book of Knowledge(TM) - "laminations of the coil".
    It probably meant to say "laminations of the transformer" (in a typical flyback design).

    Actually large valued ceramic caps also make noise (the ceramics are slightly peizoelectric), in the audible range. I've had 22uF units "sing" in the lab (6-11kHz), even with relatively minor voltages across them.

    If it's normal? Well I have heard othewise good power supplies do this - but I've not noticed it from my 85W MBP PSU.
     

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