very loud fan noise at start up (27 imac 2010

Discussion in 'iMac' started by k999rrl, Feb 13, 2012.

  1. k999rrl macrumors newbie

    Mar 1, 2011
    hi i am using osx 10.7.3 and recently when i start up my mac in the morning the fan is extremely loud and the mac is very cold. i have to shut it down and unplug for a minute to solve this problem.
    any1 knows what is going on? the other problem is my warranty is expired on december can i still purchase the extend warranty?

    thank you very much
  2. Mac2012 macrumors regular

    Nov 6, 2011
    Yes you can and get it to the Apple store as soon as possible... could be a bad logic board, or a processor at worst. Have you tried a PRAM reset? Hold the option command r and p keys at the same time on startup... if your still getting this problem, call apple... it's under warrantee so.
  3. k999rrl thread starter macrumors newbie

    Mar 1, 2011
    thanks for your reply. the warranty expired last december so i cannot take it back to apple. il try the PRAM reset. also this only happen in the 1st start of the day. no matter how many time i shut down and restart in the same day it wont happen again. really strange...
  4. drambuie macrumors 6502a

    Feb 16, 2010
    This sounds like a thermal problem in the opposite sense - it's sensitive to cold. It could be a bad solder connection on an IC pin in the fan control or temperature sensing circuits, that causes the fan(s) to latch into high speed on physically cold startups. On a restart the iMac has warmed up enough to allow a proper connection and the cooling works normally. Enough residual heat remains in the iMac during the day to enable normal fan startups. When sitting overnight it cools enough to cause the symptoms again.

    This is conjecture on my part, but based on many years of troubleshooting weird problems.

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