LCD temperature sensor broken- fan going wild

Discussion in 'iMac' started by monkeymann, Jan 3, 2012.

  1. monkeymann, Jan 3, 2012
    Last edited: Jan 3, 2012

    macrumors newbie

    Mar 2, 2009
    so i've messed up my fans taking in and out hard drives, the whole imac fell off my desk, what?!@ :eek:
    atm my fan is going crazy so 1st question.. is it ok to use for now? it's not going to blow up in my face or anything?? the computer itself is thankfully still fully operational

    2nd question, the part that broke, it's not the actual sensor, it's the little 2 legged holder that it slots into.. those 2 legs have been bent out of shape a little and i've tried working on them but best i can manage is to slot the sensor in only 1/2 way.. wasn't good enough, fans still blaring..

    i know a few of you have had similar issues, how difficult is it to source these components? my friend is pretty handy with a solder iron if it comes to it

    as usual, all help appreciated :)

    btw, it's an imac 27", one of the latest models
  2. macrumors newbie

    Jun 10, 2010
  3. macrumors 6502a


    Dec 22, 2008
    Did you change the hard drives? Or just put the same ones back? The current iMac's fans go crazy when you replace the hard drives with non-factory models due to some different sensors that Apple bundles in their HDs. There are programs that help with this, I think.

    But if you're positive it's the display sensor, then I don't know.
  4. thread starter macrumors newbie

    Mar 2, 2009
    yeah i'm aware of that HD fan issue but i'm positive it's the display sensor thingy!

    i'm assuming i could completely turn off the fans using this program, i like the sound of that ;) , but then we have to worry about over-heating i presume?
  5. macrumors 68030


    Jun 11, 2011
    Nah, just read up and ask iMac users what speed the fans are. Idle it is 2000 RPM so I would just keep it as 3500 RPM?
    Download Here
  6. macrumors regular

    Sep 27, 2011
    I use that on all my computers. I normally keep them about 50% fan speed to keep it cool, but still keep the fans quiet. If you set SMC to a low setting, it will automatically sense the temperature and increase the fan speed from your setting as needed to keep it cool. No need to worry about over-heating!
  7. thread starter macrumors newbie

    Mar 2, 2009
    i've just booted up and the fans are whirring away, below are the result SMC results:

    23degrees celcius

    odd: 3455 (rpm)
    hdd: 1152
    cpu: 3924

    i'm not sure if you guys get my issue? i dunno.. how can SMC control the fan speed if the damn sensor ain't even working.. i've tried fiddling with those smc controls but the fan noise hasn't changed
  8. macrumors regular

    Sep 27, 2011
    make a low setting in preferences, and set SMC to that
  9. thread starter macrumors newbie

    Mar 2, 2009
    they were all set to min. Speed by default
  10. monkeymann, Jan 3, 2012
    Last edited: Jan 3, 2012

    thread starter macrumors newbie

    Mar 2, 2009
    rpm speeds remain the same, smc didn't appear to work
  11. macrumors 6502a


    Sep 16, 2008
    Surrey, BC
    smc doesn't work, it only sets the minimum speeds of the fans. We need a program that sets the maximum speeds. But there isn't one (for good reasons, people would download it and fry their computers).
    If you ever find a way to slow down the fans, a speed of about 1500-2000 should give you a good balance of cooling and quiet. That was what my fans were set at before I damaged my sensor (they were slightly higher than normal because if I left my fans at default, my hard drive would get to 60 degrees C + and I used to get kernel panics). Default is around 1000 I think, but that is too low for a maximum fan setting.

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