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32gb3gwifi

macrumors member
Original poster
Jan 29, 2011
84
0
Like my title says my new 27" iMac's CPU fan I believe (the one on the left) won't turn off when I shut down the computer. Now on to the clarification, the fans do not run loud. My CPU fan is at a constant 995 to 998 rpm no matter what I am doing. It's completely silent. The whole computer. BUT, when I turn the computer off and put my ear to the exhaust vent I can hear the motor turning. Unless it's something else clicking. But I am 95% sure it's the sound of a motor turning. Now to the question. Is this normal? For the fan to continue to run albeit completely silent even after a complete shutdown and cool down?
 
ok so i have figured out something else, when i unplug the iMac the sound goes away and as soon as i plug it back in it comes back. but i have noticed that the fan is spinning MUCH slower when its turned off than when i turn it on. it is still completely silent either way but it spins much faster when i switch the computer on. so when it is off it sounds more lick a faint clicking sound.
 
ok so i have figured out something else, when i unplug the iMac the sound goes away and as soon as i plug it back in it comes back. but i have noticed that the fan is spinning MUCH slower when its turned off than when i turn it on. it is still completely silent either way but it spins much faster when i switch the computer on. so when it is off it sounds more lick a faint clicking sound.

I have the same exact problem after I installed an OWC SSD in my 2008 24inch iMac (8,1). I am certain I correctly attached the thermal sensor to the SSD. Now after shut down or during sleep mode, I can hear a fan (I think it's the fan) still spinning -- again, this is AFTER the iMac is fully shut down. I did a SMC reset and the problem still remains. During normal ON operation, the fan is running smoothly (<1200rpm) and is extremely quiet...same as before.

Did you ever solve this problem? Would love to hear the solution.

Thanks,

Frank
 
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