bingomastersbreakout

Q: iMac CPU temperature sensor faulty?

Help required to keep an old iMac alive!

 

The CPU fan on my daughter's iMac is running fast and noisily 99% of the time, whilst MacFanControl and iStatPro are reporting zero rpm. The other 1% of the time the above apps. report the fan running at around 800 rpm. All the while, the CPU temperature is reporting 42-50c.

 

When I say fast & noisy, I mean the machine is unusably loud.

And when I say old iMac, I mean 2006 2GHz Intel Core Duo - which can't be upgraded beyond OS X 10.6.8.

 

Clearly it's not worth spending much money to keep this machine running. Equally, it more than met the needs of primary schooler until this issue.

 

Having read through several related topics on various forums, I'm set to conclude the CPU temperature sensor is faulty or detached. I'm presuming the fan itself is ok as it's evidently working!

 

Points to note:

I have reset SMC and PRAM

I have hoovered out whatever dust I can without opening the m/c up.

I'm unable to locate my Apple Hardware Test disc.

Nothing significant has happened to the iMac recently - no upgrades etc.

 

Can anyone offer up any other possibilities before I load up iFixIt and get the screwdrivers out?

 

Thanks to anyone who might be able to advise me.

Ces

iMac, Mac OS X (10.6.8), Noisy Fan

Posted on Sep 21, 2016 10:55 AM

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Q: iMac CPU temperature sensor faulty?

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  • by rkaufmann87,Helpful

    rkaufmann87 rkaufmann87 Sep 22, 2016 1:56 AM in response to bingomastersbreakout
    Level 9 (58,598 points)
    Photos for Mac
    Sep 22, 2016 1:56 AM in response to bingomastersbreakout

    You have researched this well, however you may just want to have an Apple Authorized Service Provider do the work. While you may be able to do-it-yourself you don't seem positive what part needs to be replaced. An AASP has the correct tools and can diagnose exactly what part(s) to replace. They also have easy access to the parts. While yes it may be more expensive to go that route, it also may be less expensive as you don't have to replace unnecessary parts.

     

    Good luck.

  • by bingomastersbreakout,

    bingomastersbreakout bingomastersbreakout Sep 22, 2016 1:55 AM in response to rkaufmann87
    Level 1 (4 points)
    Desktops
    Sep 22, 2016 1:55 AM in response to rkaufmann87

    Thank you for the reply - and the sage advice.

     

    Unfortunately or fortunately, depending on how you look at it, I can probably pick up a similar machine on eBay for 100-150$ - and based on past experience I'd expect an AASP to charge at least this sort of money.

     

    Perhaps naively, I'm hoping the intermittent nature of the fan noise (even though it's 99% of the time) may indicate the sensor is unseated. If that's the case there may be no parts required, just a few tools and a steady hand.

     

    The fact you suggest I've done my research reassures me I'm probably not missing something obvious, so next time I have a clear afternoon I'll get the patient on the table and prepare to operate!