iMac i7 2.93 GHz PSU buzz

Discussion in 'iMac' started by larsd, Aug 8, 2010.

  1. larsd macrumors newbie

    May 21, 2006
    Does anyone else have problems with the new 2010 iMac 27" i7 Quad Core emitting quite irritating buzzing noises when the display is sleeping or is dimmed?

    It stats buzzing when the CPU temperature reaches 50C+ and the screen goes into power saving mode.

    I documented my defective iMac here, I hope it can help others in the troubleshooting of this problem.

  2. andy.barron macrumors 6502

    Nov 30, 2006
    Bedford, England
    Sorry, I have one & do not experience that. I would send it back chap.
  3. byron_hinson macrumors 6502

    Jun 3, 2003
    Got it here on my 3rd replacement iMac - wonderful. Now I guess this one is going back too. I used to recommend iMac's to everyone but the quality control is dire these days
  4. iDisk macrumors 6502a


    Jan 2, 2010
    Menlo Park, CA
    Just send it in for a look
  5. byron_hinson macrumors 6502

    Jun 3, 2003
    Phoned up today seeing I just got it, they asked me to take it into the store this weekend and get them to look at it to see if they can fix it (I know its not an easy fix as its electrical buzzing) if they can't fix it I think I've had it this time after 3 replacements.
  6. Sir.Jonas macrumors newbie

    Aug 1, 2010
    I had the same problem with mine.
    I send it back for 100% reimbursement. I don’t have time to change it 3 or 4 time...

    Came back for PC after 5min with mac... (made in China power)



    (Sorry for my English, I usualy speak french)
  7. fuchsi macrumors member

    Aug 26, 2010
    exactly same thing over here

    I just received my first replacement, send the first one back because of that same issue (i dim the screen all the time so it was constantly there!)
    It's the same thing with the new one!

    Is this an official problem or something common that will always be there?
    don't want to wait another 2 weeks for a replacement!

  8. Serif macrumors regular


    Jul 10, 2008
    I had a similar problem on a new 2010 i7 iMac but it wasn't affected by screen brightness. There are two transformers in the iMac, one in the main PSU which is located at the left hand edge of the machine, and the step up transformer used by the screen which is located near the top edge.

    My problem was with the transformer in the PSU. I preferred to get the problem fixed rather than a refund on the grounds that at least I'd know that the screen was alright and the hard drive quiet. The Applecare guys replaced the PSU and before returning it did a full hardware diagnostic as a matter of course. They then told me that the diags had spotted a problem with the graphics card too and that they'd need to replace that also. So they seem to do a fairly thorough job and I'd prefer to take my chances with a repair than spin the wheel to see what turned up if I sent it back for a straight replacement.
  9. fuchsi macrumors member

    Aug 26, 2010

    yeah that's actually a good idea...cause from what i have been reading it seems like alot of Imacs are being sent out with this problem. did somebody say quality control?
    And like you mentioned there's always the chance when u replace it that you get a new one with the same issue!

    May i ask how much time it took all in all when repaired?(sending+return)

  10. Felias macrumors member

    Jul 29, 2010
    Speaking from my experience 80% of all iMacs have this issue more or less.

    I've had 4 models, 2 had a severe buzz, 2 a mild one. My current 2010 iMac i7 does have a mild one.

    Reading your case information, i'd say you have a mild one as well. Looking at all the other things that can be wrong, i'll stick to this one.
  11. fuchsi macrumors member

    Aug 26, 2010
    Yeah it seems like alot of them have this issue...Plus mine has dust under the screen and the hard drive makes random "knocking" sounds when in sleep modus (anyone heard about those?)

    keep it or exchange? there are perfect one out there :) and considering the money you have to pay to get one of these machines it's really a tough decision to make...
    It just takes away the shimmer of the event of buying an Imac

    It's been really stressy and time consuming and that should normally not be part of the purchase...seems like apple dropped the ball here
  12. Jazwire macrumors 6502a


    Jun 20, 2009
    Guess I'm lucky, mine is dead silent.
    Or all the years of loud music have ruined my ears one of the two.

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