Imac 2011 fan trouble

Discussion in 'iMac' started by knucles_17, Apr 15, 2016.

  1. knucles_17 macrumors newbie

    Aug 6, 2015
    Hi guys,

    I nee your help once again.

    I bought an Imac 2011 i5 off ebay in a good deal but i am having one minor hiccup:

    The HDD was replaced and the hdd fan is spinning a lot, in fact my perception is that they all are.

    I can hear the fans from the other room.

    I installed several fan control apps (smc / fan control) and they tell me that the fans are at 1200rpm which seems reasonable but that info is not compatible with the noise the imac is making.

    Now i am going to swap the hdd for an ssd so i will be opening it anyway.

    Could i remove the hdd fan altogether?

    Many thanks

    It is possible that something else is triggering the cpu fan?
  2. stuartak macrumors member


    Feb 21, 2016
    I would not attempt to remove the fan , if the fan is only doing 1200 you will not hear it , if it has not got the SMART lead plugged in no third party software will work , the software (including OSX) needs to be able to read the HDD temperature.

    If you check your connections to the drive you should have the SATA cable , pus a power cable , which is longer , plus a small plug pushed onto some pins with two wires going to the Logic board , which is marked as HDD temp , if that lead is not connected or missing you need to get one , changing the HDD will not make any difference to the fan running . Apple fits three makes of HDD , Hitachi , Seagate and Western Digital , I always use Western Digital and the connections for its SMART lead ( which is the same protocol used by all the HDD manufacturers to monitor the hard disc temp (among other things)are connected to different pins on the hard drives. The Western Digital uses the two pins nearest the sata connector on the top row. I have fitted many replacement HDD and had no trouble with the fans as long as I replaced the SMART monitoring lead.
  3. knucles_17 thread starter macrumors newbie

    Aug 6, 2015
    Thanks, a few questions though:

    - if the smart plug is not pluged how can it mark 1200rpm?

    - I am putting an samsung 850 500gb, should i connect the smart connector? If yes where and why?

    - If i am using an ssd the fan is doing nothing relevant right?

    - can the hdd fan trigger the cpu one?
  4. stuartak macrumors member


    Feb 21, 2016
    Just another thought if you are fitting an SSD you can make a Fusion drive with your existing HDD , the 2011 Imac has an extra SATA socket on the back of the logic board next to the ODD SATA , although Apple did not introduce the Fusion drive option until 2012 , they shipped Imacs with the hardware necessary from mid 2011.
  5. MetalCores macrumors regular


    Apr 30, 2015
    Mosinee, WI
    Temp sensor for the hard drive. OWC makes a aftermarket one you can get and just stick to the drive.
  6. stuartak macrumors member


    Feb 21, 2016
    Your system cannot read the fan speed if the sensor is not connected , the reading you are getting is probably the default minimum of the smc or whatever fan control you are using.The two wire SMRT connector is meant to go in the HDD SSD's don't have the connector . You would be better leaving the HDD in and fitting the SSD in the spare SATA andowering it with a cable from your HDD , you need a Molex to SATA splitter cable they are only a few $ . you would however need to connect the SMART cable to the HDD.
    With reference to taking out the HDD fan , the OS expectas to "see" the fan if you remove it you could get into the system assuming there is a fault , also the fan is there to generally push air through the case , IMac cooling is a complicated issue not to be fooled about with . I have repaired a number of machines where folks have taken out the ODD and messed up the cooling to the graphics card.
  7. knucles_17 thread starter macrumors newbie

    Aug 6, 2015
    Hi guys, thanks for the feedback, after 10 assemblies/disassemblies i finally nail it this morning.

    The fans were still blasting after installing MAC Fans Control and the OWC thermal accessory so i was in trouble.

    I noticed (with istat pro) that the ODD fan marked 0RPM even though i was at full speed. i took everything apart (again) to check the connectors - everything seemed fine but i decided to take the fan out and then i found the problem!!!

    The screw that connects the logic board to the case was smashing one of the ODD fan cables, to it out, cut the smashed part, joined the cables back together and duct tapped it together. [solved]

    now i have a:

    Imac 2011
    SSD - samsung Evo 250gb
    20gb Ram

    Total price: 684$

    Thanks for your help

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6 April 15, 2016