Fan stuck on high

Question

hackwojr Author

Level 1

10 points

Fan stuck on high

Just got my iMac back from the Apple store - they replaced the logic board.

Anyway, now the fan is very audible (never was before unless CPU process or temp got high).

System (CPU) is 93% idle.

Temps are all less than 50, except CPU and CPU diode - those are 55.

Fan speeds are Optical drive 5000rpm, Hard drive 1400rpm, CPU 842rpm.

Not sure which is being noisy, but I don't think a new logic board should make it noisier - but maybe the faulty one was my very quiet iMAC before the logic board change.

Any help would be appreciated. Is this normal behavior? I know there are widgets to control the fan spead - I'd rather have the computer do it automatically and appropriately.

Thanks!

Oh, and I am running 10.6.8

iMAC 20inch, Mac OS X (10.4.8), with Windows XP

Posted on Aug 28, 2011 9:07 PM

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Answer 1

rkaufmann87

Level 10

148,494 points

Aug 28, 2011 9:54 PM in response to hackwojr

Do a SMC reset and if that doesn't fix it back to the store you go!

SMC RESET

Shut down the computer.
Unplug the computer's power cord and all peripherals.
Press and hold the power button for 5 seconds.
Release the power button.
Attach the computers power cable.
Press the power button to turn on the computer.

PRAM RESET

Shut down the computer.
Locate the following keys on the keyboard: Command, Option, P, and R. You will need to hold these keys down simultaneously in step 4.
Turn on the computer.
Press and hold the Command-Option-P-R keys. You must press this key combination before the gray screen appears.
Hold the keys down until the computer restarts and you hear the startup sound for the second time.
Release the keys.

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