Does 21" mid-2010 have in-disk fan sensor?

Discussion in 'iMac' started by hfg, Nov 23, 2013.

  1. hfg macrumors 68040

    hfg

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    #1
    I would like to put a SSD in place of the HD on my wife's 21" Mid-2010 iMac 11,2 model. Does anyone know for sure if there will be fan issues due to the hard disk being removed (internal temp sensor)?

    If so, is there a hardware workaround such as a plug in temp sensor which can deal with the fan speed, or is a software solution the only answer for the fan overspeed.


    Thanks in advance ...


    -howard
     
  2. SandboxGeneral Moderator

    SandboxGeneral

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    #2
    Yes there is a sensor that plugs into the jumper pins. I took a control board from a dead HDD and plugged the sensor into it and mounted it to the SSD and the fans behave properly.
     
  3. hfg thread starter macrumors 68040

    hfg

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    #3
    That is a clever idea to just use an old disk controller board. I assume that there is a thermistor or something on the board connected to those extra pins ... but are they on ALL brands, sizes, and generations of drives? There may be a difference with WD vs. Seagate since I have seen replacement instructions that required the replacement drive to be the same brand due to the temperature wiring. I looked at the tech specs available at the WD website and couldn't find a functional description of that pin-field.

    I suppose one could just scrap the old drive and remove the controller for this purpose (an old worn out small disk drive isn't worth a whole lot used). :)

    If it is a simple thermistor, I would think someone like OWC would sell just the part (small "blob" with 2 leads sticking out) which could be stuck into the connector and then taped to the drive exterior to perform that temperature feedback function. Interesting that OWC doesn't provide replacement or upgrade disks for the 2010 model 21" iMac ... they have the 27" 2010, and the 21" 2011 model, but not this one.

    Thanks for the link...

    -howard
     
  4. SandboxGeneral Moderator

    SandboxGeneral

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    #4
    To the best of my knowledge the only way the Mac get's the temperature is by sensing the temperature of the jumper pins through the cable. This would mean that the controller board is just a dummy to provide the pins. The controller bard I used came from a 10 year old Compaq server HDD that had previously failed.
     
  5. hfg thread starter macrumors 68040

    hfg

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    #5
    That would require the actual temperature sensor to actually be in the connector itself on the end of the cable going to the motherboard.

    If so, just leaving the cable hanging there would work, as it would measure the temperature of the contacts in the connector shell which would work just as well as the physical pins of the drive for at least measuring the free-space temperature in that area. This is of course assuming that there is no temperature issue due to the replacement with a SSD.
     
  6. SandboxGeneral Moderator

    SandboxGeneral

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    #6
    Well, all I know is when I left the cable hanging free I had plenty of issues with the HDD fan spinning at full RPM. Once I connected the dead controller board, that all stopped and the fan remains steady between 1100-1300 RPMS.
     
  7. cinematicme macrumors member

    cinematicme

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    #7
    You can always use a 3rd party SMCfan controller for example macs fan control or smcfancontrol
     
  8. SandboxGeneral Moderator

    SandboxGeneral

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    #8
    That works most of the time, but if you use the wake for network access on the machine, then it won't work and the fan will spin up to full RPM. That was the one thing I couldn't fix with software.
     
  9. hfg thread starter macrumors 68040

    hfg

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    #9
    Since this is my wife's computer, I want to avoid software solutions in favor of a hardware solution which wouldn't require any monitoring or attention on the part of the user.

    I think the "old disk controller board" trick looks to be a good solution and is easy to implement with no downside that I can see.


    -howard
     
  10. SandboxGeneral Moderator

    SandboxGeneral

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    #10
    It's been several months now and I haven't had one single solitary problem with it. :)
     

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