Results 1 to 8 of 8
  1. #1


    Member Since
    Sep 07, 2011
    Location
    Maryland, USA
    Posts
    8
    Specs:
    Late 2006 2.16 GHz Core 2 Duo 15"
    SMC has given up on fan control
    My friend has an early 2006 15" Core Duo 1.83 with a serious SMC problem. After cruising the forums, I've gathered that this model is notorious for overheating. So here's how I've reached my diagnosis:

    --She complains that computer gets hot and shuts down unexpectedly with moderate use of CPU
    --battery cycles are dead due to unnecessary power usage
    --After running CPU stress test and monitoring temperature, it read that her core was tripping shutdowns at 255 degrees F (123C!!), with no fan response
    --Downloaded SMCfancontrol and tested fans, manually setting on 5,000rpms- system hovers around 215F (100C) on load, which is still not good
    --reset SMC and PMU
    --physically inspected fans for blockage or mechanical failure
    --when manually setting fans at higher minimum rpm, fan speeds DO increase, but at a very slow rate and only tops out at 3,500 rpm at the core's hottest temp.

    SMC IS communicating with the fans, but very poorly, and it would be a serious inefficiency to run the fans high all of the time. Any thoughts? Thanks

    -mJ
    OS 10.6.8

  2. #2

    harryb2448's Avatar
    Member Since
    Nov 28, 2007
    Location
    Nambucca Heads Australia
    Posts
    22,014
    Specs:
    Imac 27" Retina 5K, 512GB Flash Storage, 3.3Ghz, 16GB memory, OS X.11.5.
    Sounds like it needs a good clean out. Dust is the prime enemy of all computers, particularly iMacs.


    http://www.ifixit.com/Answers/View/1...tel+Core+2+Duo
    Hang on to those original install discs like grim death! Using OS X.7 or later make a bootable USB thumb drive before running Installer!

  3. #3


    Member Since
    Sep 07, 2011
    Location
    Maryland, USA
    Posts
    8
    Specs:
    Late 2006 2.16 GHz Core 2 Duo 15"
    Already checked fans for dust. While it could be they need lubricating, that still doesn't address why the fans do not respond to extreme temperature increase without manual instruction.
    OS 10.6.8

  4. #4

    BrianLachoreVPI's Avatar
    Member Since
    Feb 24, 2011
    Location
    Maryland
    Posts
    3,733
    Specs:
    March 2011 15" MBP 2.3GHz i7 Quad Core 8GB Ram | Mid 2011 27" iMac 3.4 GHz i7 16 GB RAM 2 TB HDD
    You're saying fans - plural. Is this behavior the same for all fans or just the CPU? It's entirely possible that you just need a new fan after 5 years.

  5. #5


    Member Since
    Sep 07, 2011
    Location
    Maryland, USA
    Posts
    8
    Specs:
    Late 2006 2.16 GHz Core 2 Duo 15"
    Both fans function at all speeds when manually set, but do not increase their RPMs automatically with temperature rise - that's why I'm ruling out a hardware issue, unless there is some SMC communication wire I don't know about that is loose or something.
    OS 10.6.8

  6. #6

    chscag's Avatar
    Member Since
    Jan 23, 2008
    Location
    Fort Worth, Texas
    Posts
    48,517
    Specs:
    Late 2013 27" iMac, iPad 3, iPhone 6s+, iPhone 6+, 3 iPods, El Capitan
    A machine that is 5 years old is probably going to experience getting warmer than one which is newer, however, those temperatures are unacceptable. It sounds like the temperature sensors are not working or the thermal paste on the CPU heat sink is almost gone. Either defect especially the lack of thermal paste will drive temps up quick.

    Use the instructions at iFixit: The free repair manual to take the machine apart down to the logic board. Inspect the CPU area heat sink and the GPU to see if there is enough thermal paste left to provide the proper heat transfer. Also take a look at the thermal sensors to see if they're cracked. Not much you can do to test them though. Just have to swap them out.

    I'm not sure if a machine that old is worth putting money into. A decision that the owner will have to make.

  7. #7

    BrianLachoreVPI's Avatar
    Member Since
    Feb 24, 2011
    Location
    Maryland
    Posts
    3,733
    Specs:
    March 2011 15" MBP 2.3GHz i7 Quad Core 8GB Ram | Mid 2011 27" iMac 3.4 GHz i7 16 GB RAM 2 TB HDD
    Well- you really can't rule out HW based on the information you've provided. You indicate that the fans (you don't say which ones and I would be surprised if they were all behaving exactly the same way) respond to SMC control - but slowly and never exceed 3500 rpm in spite of being told to. You say they don't ramp up themselves at all - even if the CPU is baking. You're really only left with HW issues - but potentially 2 of them if what you're saying is true. Your temp sensors must not be working correctly, because the data paths for the fan instructions are fundamentally the same AND your fans must have some issues since they can't reach max speeds and respond very slowly. I think you're definitely looking at a HW issue - but difficult to say exactly what from here.

  8. #8


    Member Since
    Sep 07, 2011
    Location
    Maryland, USA
    Posts
    8
    Specs:
    Late 2006 2.16 GHz Core 2 Duo 15"
    Thanks everyone for the amazing insight - I'm pretty savvy with taking apart Macbooks, but I wasn't aware of the temperature sensing HW- I figured there was some internal component that could be the culprit with bad temperature communication, but I couldn't put specific HW to it-

    now to get my hands greasy with thermal paste...
    OS 10.6.8

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. Why smc Fan Control?
    By T_O_P12 in forum Switcher Hangout
    Replies: 9
    Last Post: 04-24-2010, 10:21 AM
  2. Question about 'SMC Fan Control Application'
    By achi21smile in forum OS X - Apps and Games
    Replies: 1
    Last Post: 01-06-2010, 04:08 PM
  3. smc fan control giving me issues
    By I_LOVE_MY_MAC in forum Switcher Hangout
    Replies: 5
    Last Post: 12-15-2009, 09:59 AM
  4. Smc Fan Control with Intel Imac
    By Dspg_Asap in forum OS X - Apps and Games
    Replies: 2
    Last Post: 08-08-2007, 02:13 PM
  5. Anyone use SMC Fan Control?
    By Scremox in forum OS X - Apps and Games
    Replies: 11
    Last Post: 06-09-2007, 11:23 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •