Turning fans on via switches, want to make sure.....

Discussion in 'Modding' started by Lukey, Jan 12, 2007.

  1. Lukey

    Lukey Member

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    Ok, so i'm hooking up some fans to switches that look like this:

    [​IMG]
    (excuse the terrible pic, macro on my mums camera sucks and mine is at dads)

    It has connections like this:
    [​IMG]

    And I'm wanting a fan with a connection like this:
    [​IMG]
    To hook up to it so I can readily turn it on and off.

    Here is a whole bit of the fan:
    [​IMG]


    Do I simply snip the connector end of the fan off and hook all three wires up to one connector on the switch, and somehow attach the psu to the other connector on the switch, or what?

    Thanks :D

    EDIT: And sorry, I should have downsized pics even more....
     
  2. neon_87

    neon_87 RIP

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    okay - your switch has 2 connectors to connect one of the fan wires.

    Your fan has 3 wires correct? a red (+) black (-, or gnd) and a yellow or another colour, which is for the fan speed monitor.

    What you want to do, is snip the red wire, and join the two snipped bits to the switch, hence switching the circuit on and off. that cable you have pictured looks to me like a USB header or something of that type.

    You'll want a 3-pin plug, to connect the fan to your motherboard, or a 4 pin molex plug to connect to your power supply.

    (a) 3-Pin Fan Connector

    [​IMG]

    (b) 4-Pin Molex Connector

    [​IMG]

    If you want to use the fan's speed monitor, use the 3-pin connector (a) and hook it up to the motherboard - BUT if the fan is a very high speed fan, and uses large ammounts of power, its possible you can burn out the motherboard header, so you should use the molex connector (b) - and plug it directly into your power supply.

    When hooking the cables up to the plugs, make sure you have the cables in the right way (look at another cable inside your system to be sure). On the molex cable, the two black wires can go in any which way provided they are the two in the center.

    Hope that helps.
     
  3. OP
    OP
    Lukey

    Lukey Member

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    Yeah that's right :D
    Ok, you said two, but you only told me to cut the red wire? So do I just attach the one red wire to one of the connectors on the switch?

    Yeah they're big 120mm Sunon's, so I think i'll go with this option. Where can I buy these from btw? Just the 4 pin molex connector to bare wire so I can attach it to the other spare connector on the switch?
    Sorry I don't understand this bit, my mind is reading it in another way to which you intended I think. Any visuals please? (sorry for being so stupid)
    Yes it did heaps, thanks.
    Just need a little more info if able to, cheers :)
     
  4. nux

    nux Member

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    Your switch looks to be a single pole switch, so it can only switch one thing on/off.

    So you would leave the ground wire connected as is, and just put the switch somewhere on the red positive wire.
     
  5. OP
    OP
    Lukey

    Lukey Member

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    Ok, but then i'm still left with this weird bloody end thing. So should I cut the wires and get a 4 pin molex and connect that to it so I can plug it into psu?
     
  6. Shinanigans

    Shinanigans Member

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    Hey sorry, but just a quick hijack on topic....

    Just reading the manual for my Asus M2N32SLI board it says:
    Taking a look at an Antec 80mm fan for example, it says 0.14A as it's current draw. There are four CHA_FAN connectors available on this motherboard. Given the specs from Asus, how many chassis fans could i safely use? And do you interpret those above specs as the details for EACH fan connector, or all four? I assume each, but just want to make sure. Don't want to pop a $300 board!
     
  7. neon_87

    neon_87 RIP

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    0.14A is 140mA, so you'll be fine with all four :)

    Lukey - Cut the red wire where you want the switch - then put the switch in place of the cut.

    Molex switches can be bought at DSE and Jaycar, and loads of general electronics stores - should cost about a dollar.

    When wiring up the molexes, you have to make sure than when you plug your made plug into one from the power supply, the wires match up - so red to red, and yellow to yellow - else you could do some serious damage - but in case of a fan - it will only slow the fan down as it will run from 5V instead of 12V. The Two black wires (ground) go in the two center pins, shown in my previous post. Since you only have 1 ground wire for your fan - pick one of the two to use. You can snip, or cable tie up the yellow wire, as you wont need it for the molex plug - and its likely just to get in the way.

    Hope that helps :)
     
  8. OP
    OP
    Lukey

    Lukey Member

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    Yeah sweet as, got it all now. So if I wanna make it longer, I could simply cut all wires and and use pretty much any sort of electrical wire to make them longer yeah?

    Just solder them up and insulate them correctly? Or is this a big no no? :p
     
  9. neon_87

    neon_87 RIP

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    a quick drawing to demonstrate:

    [​IMG]


    NOTE: YELLOW FAN WIRE AND +5V LINE ARE NOT THE SAME! DO NOT PLUG THEM TOGETHER!
     
  10. OP
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    Lukey

    Lukey Member

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    That was a bloody nice paint job! Thanks :D

    Now if I ever get confused, i'm safe :p. So for extending the lengths of the wires can I just cut them and put some electrical wire in? Because it won't be long enough to reach where I want it.

    I assume this is all good to do? :)
     
  11. Captain Kermit

    Captain Kermit Member

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    [​IMG]

    Red line=red wire
    Black line=black wire
    yellow line=yellow/misc colour wire

    Purple=switch
    Blue=fan
    Light green= 3 pin connector already attached
    dark green=Motherboard.
    And presto. Put switch in on position, fan is on, put it in off, fan is off.


    EDIT: Started drawing this about 30 mins ago. Mum came and distracted me with phone plans and other such nonsense. With my diagram, you'll only need to make 1 cut since the fan already has a 3 pin plug attached. You can just extend the red wire, don't bother extending the others, unless you enjoy soldering, or want to practice on something of little consequence.
     
    Last edited: Jan 12, 2007
  12. neon_87

    neon_87 RIP

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    you can extend the wires if needed, yes.
     
  13. Shinanigans

    Shinanigans Member

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    If you had a 3 way switch (1, 2, off) could you wire up 1 to the +5v, 2 to the +12v and off to nothing? So it's basically a speed controller and an on/off switch in the one switch?
     
  14. sevenAU

    sevenAU Member

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    Thanks for that, great diagram!
     
  15. OP
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    Lukey

    Lukey Member

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    I second this :p. And also curious about what 2 posts up says.
     
  16. Captain Kermit

    Captain Kermit Member

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    A three way switch is a switch that has 3 positions. What he's saying is you could connect one position to 5v and one position to 12v, while the other position is off. So effectively, you could control the speed of your fan with one of these switches. Only problem is that some fans won't spin up at 5v, but will run on 5v if you get it moving first. Others do start up and spin on 5v fine. And other may just refuse to spin at all on 5v, even if you get it moving first.

    Another way of controlling your fans speed is to use the 7v mod trick. To do this, connect the +ve wire of the fan to the Yellow wire on the molex plug and the -ve wire to the red wire on the molex plug, and your fan will spin at a slower speed. That way you could use a 3 position switch to make the fans spin at either 7v or 12v.
     
  17. Abug

    Abug Member

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    Great drawing to help him Neon_87 but one problem.

    The Red wire on the molex from the PSU is the +5v and the yellow is the +12v rail.

    Thus the red wire going to the fan should align with the yellow wire of the PSU molex.
     
  18. OP
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    Lukey

    Lukey Member

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    Wow this is getting even cooler, any chance of a diagram for a 3 way switch with the volt mod? ;). I think I might put this up as some sort of guide, "Using switches to control fans; for dummies".
     
  19. 1337_g4m3r

    1337_g4m3r Member

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    from my experiences in doing this, a 120mm fan will NOT power on with 5v, itll twitch a bit and sometimes itll just start up after a while, i have ran the 120mm at 5v, but ur better off with the 7v mod.

    i had mine set up to run 12 v, off, 7v and they ran fine for ages, but then i got a newer power supply and it would shut off whenever i tried to run my fans at 7v, no matter what i did.

    so i had to change my whole set up :(
     
  20. nux

    nux Member

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    Yes of course, or use the 7volt trick.

    http://www.fanbus.com/faq/fanfaq.htm

    Just search for '7volt trick' or '7 volt trick' etc in Google..
     

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