Resolved iMac 21.5 2011 fans at full speed after adding an SSD.

Discussion in 'iMac' started by Bruno09, Oct 11, 2016.

  1. Bruno09 macrumors 68020

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    #1
    Hi all,

    I need some help.
    Please pardon my poor English.


    I just added a Crucial SSD in a 21.5" 2011 iMac, using iFixit tutorial.

    All went fine, no issue at all.

    First boot after re-assembling : the CPU and optical drive fans run at full speed.

    The hard drive fan is ok.

    An SMC reset did not solve the problem.

    I installed MacsFanControl on the HD to slow down the fans, MFC offers to use the CPUs or CPU heatsink thermal sensors and the optical drive sensor, so it seems that MFC "sees" the sensors.

    Then, I installed El Cap on the SSD and used Migration Assistant to migrate the accounts from the HD to the SSD.

    First boot from the SSD : the fans are silent, MFC is not needed, all run smooth as expected.

    Having some maintenance to do on the HD, I boot on the HD, then reboot in safe mode.

    As a result, the CPU and optical drive fans run at full speed again.

    SMC reset does not solve the problem.

    (NVRAM reset just in case).

    I open the Mac again, check the connectors, unplug and plug back the thermal sensors connectors, complete the re-assembling and boot from the SSD : fans still running at full speed.

    Just in case, I reinstalled El Cap on the SSD without erasing it.

    The problem is still here.

    Now I have no idea about what to do to solve this issue.

    - MacsFanControl "sees" the thermal sensors, and when using them, it does regulate the fans speed.

    - iStat Pro does NOT see the sensors, it only displays :
    HD temp
    SSD temp
    Ambient temp


    No CPU, no CPU heatsink, no GPU, no optical drive temp displayed.


    What do you think : hardware or software issue ?
    Did I hurt the connectors in any way, despite they look fine ?


    Thank you for any help in advance.
     
  2. rmm805 macrumors member

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    #2
  3. Bruno09 thread starter macrumors 68020

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    #3
    Thank you for your response.

    I did NOT replace the hard drive, I added an SSD.

    The original HD stays in place an its thermal sensor was not removed.
    (BTW, its fan runs at normal speed).
     
  4. lcseds macrumors 6502a

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    #4

    Since the system was designed to look for thermal sensor readings from internal drives, your SSD is not exempt from requiring a thermal sensor cable as linked above. Just like adding another hard drive, another sensor is needed, HDD or SSD. You have one drive with, one without, that will cause a sensor "fail".
     
  5. rmm805 macrumors member

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    #5
    I have replaced both my factory SSD and my factory HDD in my 2011 and I needed to use an adapter for each one. It's tricky to fit them in there but it gets rid of the fan issue.
     
  6. Bruno09, Oct 11, 2016
    Last edited: Oct 11, 2016

    Bruno09 thread starter macrumors 68020

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    #6
    Thanks you for your help.

    I have no problem reading the SSD temperature : iStat pro does show both the HD temp AND the SSD temp.

    My configuration is the same as the original Apple BTO iMac with HD + SSD.
    From Apple repair guide : http://hpics.li/e6920c5
    My upgrade : http://hpics.li/571d1b8

    I have used the OWC SSD upgrade kit, no other part is needed : https://eshop.macsales.com/item/OWC/DIYIM21SSD11/

    iFixit tutorial : https://fr.ifixit.com/Guide/Installing+iMac+Intel+21.5-Inch+EMC+2428+Dual+Hard+Drive+Kit/6434
    iFixit video : youtube]RmLLzkg3vI0
    OWC tutorial (see video included) : https://eshop.macsales.com/item/OWC/DIYIM21SSD11/

    Much more important : I recently did the very same upgrade for FIVE 27" mid-2011 iMacs, using OWC kits and Crucial SSDs and had NO problem : http://hpics.li/b19b158
     
  7. rmm805 macrumors member

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    #7
    That's weird then. I'm not sure. So the OWC kit to add an SSD in addition to your HDD has a thermal component built in?
     
  8. Bruno09 thread starter macrumors 68020

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    #8
    I don't know if the temp info comes from the OWC connector or from the SSD itself, but it actually comes and the reading is correct (from ~20°C at boot time to ~30°C after some time).
     
  9. lcseds macrumors 6502a

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    #9
    I've done plenty also. But since you know better, I doubt anyone here can help you.
     
  10. Bruno09 thread starter macrumors 68020

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    #10
    Thank you for your message.

    Tomorrow I will run an AHT and install iStat Menus to get more infos about the temp sensors.

    What I find very strange is that I had no fan issues after installing El Cap on the SSD and using Migration Assistant : all worked perfectly.
    I was able to login, check that all was fine, wait for the indexation to complete, without fan noise.

    This is only after a (safe) reboot on the HD that the 2 fans started to run at full speed again.
     
  11. Bruno09 thread starter macrumors 68020

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    #12
    Thank you for your response.

    I use MacsFanControl but I need to solve the problem so that no third party software is needed.
     
  12. Bruno09 thread starter macrumors 68020

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    #13
    Here are the results of the AHT :

    - Basic tests :
    Error code : 4SNS/1/C0000008:TC0H --124
    TC0H refers to the CPU Heatsink thermal sensor

    - Extended tests :
    Error code : 4SNS/1/1C0000008:TS0p --124
    TS0p refers to the sensor located to the right of camera

    - Basic tests again :
    Error code : 4SNS/1/1C0000008:TS0p --124
    TS0p refers to the sensor located to the right of camera
    No more error code for the CPU sensor ?

    iStat Menus gives inconstant results (reboot between each result).
    1. http://hpics.li/0f055a7 (sensors missing)
    2. http://hpics.li/3ebf763 (sensors present with temp values)
    3. http://hpics.li/10d1967 (sensors present, with some temp values missing)

    MacsFanControl (MFC) stil offers to use the CPU and optical drive sensors and displays temp values for these 2 sensors.

    According to the AHT, there is no issue with the optical drive sensor, however its fan keeps running at full speed when MFC is off.

    I wonder why the extended AHT does not give an error for the CPU sensor, as it does with the basic test ?
     
  13. Bruno09, Oct 14, 2016
    Last edited: Oct 15, 2016

    Bruno09 thread starter macrumors 68020

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    #14
    Please could someone using a 21.5" Mid-2011 iMac and iStat Menus share the output for "Sensors", so that I can compare with mine and check for missing sensors ?

    Many thanks in advance.

    Mine : http://hpics.li/9d9d538

    Also does anyone know if I should replace the logic board battery ?
    It is 5 years old, inexpensive and easy to replace.
     
  14. Bruno09, Nov 10, 2016
    Last edited: Nov 10, 2016

    Bruno09 thread starter macrumors 68020

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    #15
    Problem solved : I had just forgotten to plug in the Skin Upper Right sensor's connector.

    All is fine now, fans running silently.

    The owner enjoys his dual drive SSD-HD 2011 iMac.
     

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