Is the PSU Buzz really an issue or common?

Discussion in 'iMac' started by fuchsi, Aug 26, 2010.

  1. fuchsi macrumors member

    Aug 26, 2010
    I received my first Imac replacement today...psu buzz sound here again (even louder i would say, but just when dimming the screen)

    I looked around the web and this seems to be a common issue.
    Could it be that the buzzing is actually normal?
    E.g. my dimlight lamp at home has the same reactions
    If turned fully bright no sound - if dimmed a buzzing sound occurs.
    Maybe it's a technical reaction that always happens when an electronical device is working with different currencies.
    Send back or keep?

    What is your Opinion?
  2. dwarnecke11 macrumors 6502

    Nov 29, 2009
    I'd say if you can't hear it unless your ear is right up to the vent, it's a non-issue. That's how it is on my new i7. What bothers me more is a speck of dust trapped between the backlight and LCD.
  3. fuchsi thread starter macrumors member

    Aug 26, 2010
    Haha i also have the tiny speck of dust :-D
    And i can hear my buzzing sound from where i sit...
    On the first imac it was lower :-(

    Maybe third time is a charmer!
  4. Poob Bubes macrumors 6502a

    Poob Bubes

    Apr 16, 2007
    My first BTO i5 had the buzz, but the replacement was buzz free.
  5. Btom macrumors 6502a

    Nov 19, 2009
    PSU is supposed to be quiet. Audible buzzing means PSU is unstable under changing load conditions and goes into parasitic oscillations, also may fail sooner.

    Tom B.
  6. fuchsi thread starter macrumors member

    Aug 26, 2010
    Thanks for the info Btom
    Sounds like it's really an issue :-(...hmm maybe i will send it back after all

    by the way what the heck are parasitic oscillations?? :)
  7. fuchsi thread starter macrumors member

    Aug 26, 2010
    God damn it!
    3rd Imac and the Issue is still there!...seems to be something that won't go away in the replacement roulette..maybe it really has to do with the electricity current over here in europe...
    To add insult to injury the new one has a weaker screen and HD noise

    The long way home goes on
  8. Felias macrumors member

    Jul 29, 2010
    I also have this issue, but only in a minor way. I've hat 3 other iMacs before who had it really bad. With my current model i only hear it when being close by, and thats okay with me. After exchanging 3 times, thats enough...
  9. fuchsi thread starter macrumors member

    Aug 26, 2010
    Yeah actually the first one i received was ironically the lowest PSU noise producer,
    i'm keeping the second one...thank god that i had the chance to compare since the third and last replacement is the loudest and has the yellow tint (slightly)
    So that one is going back!...well at least i hold on to one that has a fabulous screen :-D

    but in all seriousness Apple should come out of denial and do something against this issue!
  10. SnowOwl macrumors newbie

    Aug 31, 2010
    I am in the exact same situation.
    I've only had my imac 5 days and feel that if I send it back I'l get something worse but also feel like if I do nothing the problem could get worse!

    This is really causing me unhappiness.

    See here:

    I really don't know what to do.
  11. clearyjp macrumors member

    Oct 6, 2007
    Sydney, Australia
    How did you get Apple to send out the 3rd one while you were still in possession of the 2nd one?
    I'd like to return my 5th because of a blue patch and dead pixels but I'm afraid I'll get something worse
  12. SnowOwl macrumors newbie

    Aug 31, 2010
    So what is everyone doing?

    Are you keeping your buzzing imac not knowing if the issue could cause problems later OR are you getting a replacement that might fix the buzzing but could give you a machine with another problem?
  13. fuchsi thread starter macrumors member

    Aug 26, 2010
    well the third replacement was here in 3 days (over the weekend)
    so i still had the second one cause i couldn't arrange a pick up appointment with the parcel service yet.

    I called AppleService today again to tell them the third one is even more flawed then the second one and i would like to keep the second one rather than none!
    The bird on the phone started flipping out and telling me thats not i insisted and she called her manager and figured it out.
    For all the praise i had the other day i must say i really got the other end of the service spectrum today!
    The "lady" was really condecending in her tone and not helping out at all.
    Her advice was to get another model!
    I was like "but i want the imac 27 i7 and i don't want to exchange imacs around for a whole moth until the company manages to send flawless computer, i gotta work with this thing!"

    So i guess the buzz sound is "normal", cause let's be honest twice maybe bad luck but three times? it looks like it's here to stay

    I mean look around...almost everybody has the PSU noise so it can't be a coincidence
  14. Appleness macrumors member

    Feb 26, 2009
    So, isn´t there any 27 i7 PSU buzz free out there?
  15. CBJammin103 macrumors regular


    Jun 6, 2007
    Louisiana, United States
    I've got a 27" i7... no buzz, no yellow tint, a bit of an observable backlight bleed around the edges on a pitch black screen, but not really noticeable without looking for it.

    So there are definitely good models... in fact no one I know with a new iMac (granted, only a couple of people as I'm a college student) has any of the reportedly popular issues.
  16. Consultant macrumors G5


    Jun 27, 2007
    Maybe you have some disease of the ears.
  17. SnowOwl macrumors newbie

    Aug 31, 2010
    I see you are based in the U.S.
    This seems to be affecting more people in Europe for some reason.

    Mine is very faint so I am going to live with it for the moment I think.

    I have AppleCare so if anything goes wrong I'l sort it then.

    But it would be interesting to find a fix sometime soon.
  18. fuchsi thread starter macrumors member

    Aug 26, 2010
    Yeah it seems to be a problem occuring in europe.

    Has to do with the diffent DC over here
  19. SnowOwl macrumors newbie

    Aug 31, 2010
    Oh well for the moment no sleep for my imac and just complete shut downs.

    If someone tinks I should take advantage of the 14 day return please shout now. I just feel I could get one that could be worse.

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