CPU FAN: on which cable should I solder a resistor

Discussion in 'iMac' started by nouxtywe, Jan 9, 2014.

  1. nouxtywe macrumors newbie

    Jan 6, 2014
    Hi guys,
    Could an expert give me some advice about how to solder a resistor to the alimentation of my CPU Fan?
    Because I have the exact same problem of this guy :

    Cpu fan @ Max speed but SMC displaying 0 rpm.

    I'm gonna do it, but I kinda need some more intel because I don't want to screw everything up :)
    A photography or a technical sheet would be the best... but I'm dreaming I guess :)

    Here's the piece of the iMac (from ifixit)

    Thanks for your help!
  2. thejadedmonkey macrumors 604


    May 28, 2005
    My guess is that you can put the 100ohm resister on either wire, and it will sufficiently slow down the fan speed. It won't sound like a jet engine, but remember it will also prevent the fan from ever going any faster than that speed, which could cause overheating.

    But yes, either the black of white wire. It shouldn't matter if it's on the ground or powered line.
  3. nouxtywe, Jan 9, 2014
    Last edited: Jan 9, 2014

    nouxtywe thread starter macrumors newbie

    Jan 6, 2014
    First, thanks a lot for your interest and your comment :)
    Can you assure me that those 2 wires I pointed on the last pick are the powered line?

    Thanks again :)

    So it would be the cable #2 on those pics, right?
  4. nouxtywe thread starter macrumors newbie

    Jan 6, 2014
  5. BJonson macrumors 6502a


    Aug 26, 2010
    You have to short the hard drive temperature sensor. I stuck a wire inti both holes connecting them. That stops the fan from going nuts and keeps it at 1100 rpm. It's not the CPU fan but the hard drive fan.
  6. nouxtywe thread starter macrumors newbie

    Jan 6, 2014

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