Late 2009 27 iMac humming noise

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Late 2009 27 iMac humming noise

I have a late 2009 27 iMac that has started a persistent low range humming noise when switched on. The moment I put it to sleep or switch off it disappears and reappears as soon as it is switched on.

It does not seem to be related to the screen brightness and has not been solved by a SMC or PRAM reset.

If I lift it off the desk it stops completely. I have tried changing the desk and also putting a soft towel underneath the stand, to no avail.

Any suggestions?

Thanks

iMac (27-inch Late 2009), OS X Mavericks (10.9.5), iPhone 4 iPod 3G iPod Nano

Posted on Aug 29, 2015 3:34 AM

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Answer 1

Aug 29, 2015 4:03 AM in response to AdamMalaga

Sounds like it may be hardware related.

Make an appointment at a Genius Bar

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Answer 2

AdamMalaga Author

Level 1

11 points

Aug 29, 2015 10:58 AM in response to AdamMalaga

I had failed to mention that a year ago I replaced the Super Drive with an SSD cloned from my original HDD, but never removed it. I opened the iMac again and unplugged the HDD power and data connections. The noise seems to have gone so must have been HDD related I hope.

now I have a small problem, it seems to take OSX a little while longer (though still fast thanks to the SSD) to start and close, could it be searching for the original HDD? Can I update settings to tell OSX that drive no longer exists? Should I put the SSD in the original drive bay? I do have it setup to have the SSD as start up drive

thanks

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