Solved

How can I connect a 3 pin case fan to my PSU?

I want to attach another case fan I took from my brother's old computer but I only have one 3 pin connection in my motherboard. Is there anything I can do without buying an adapter? Can I just weld two of the 3 pin's cables to two of a molex's cables (one that comes out of my PSU) like in this picture? : http://www.logicsupply.com/images/photos/cables/pwr-mf_big.jpg

I also have a 4pin female connector coming out of my PSU, will it help?

And the last thing, can I somehow split the 3pin connection on the motherboard that I will be able to connect both of the fans to it / connect both of the fans together and connect it to the motherboard? (or will it just make both of them work slowly?)

Thanks in advance and sorry for my bad English.
9 answers Last reply Best Answer
More about connect pin case fan psu
  1. Adapters are so cheap, it's really unnecessary to splice the fan to the PSU. But yes, you can do that, if you know which wires to use. Fans are +12V DC.
    Yes, you can buy a splitter to run 2 fans off one header. But most headers are only good for 1 amp load. So besure you don't have some odd ball fan that draws too much current. Here is a splitter: http://www.newegg.com/Product/Product.aspx?Item=N82E16812226070
    While you are buying that, you might as well by an adapter too.
  2. clutchc said:
    Adapters are so cheap, it's really unnecessary to splice the fan to the PSU. But yes, you can do that, if you know which wires to use. Fans are +12V DC.
    Yes, you can buy a splitter to run 2 fans off one header. But most headers are only good for 1 amp load. So besure you don't have some odd ball fan that draws too much current. Here is a splitter: http://www.newegg.com/Product/Product.aspx?Item=N82E16812226070
    While you are buying that, you might as well by an adapter too.

    Thanks for the reply. Could you tell me which of the fan's cables goes to which of the molex's?
  3. Best answer
    The standard pin-out for a Molex cable is:
    Pin Color Type
    Pin 1 Yellow +12 V
    Pin 2 Black Ground
    Pin 3 Black Ground
    Pin 4 Red +5 V

    You will want to connect the Molex's +12V (yel) to the fan's positive (+) wire, and the Molex's ground (blk) to the fan's negative (-) wire. If the fan has red, blk, and yel wires... they will be
    red (+)
    blk (-)
    yel (tach)
  4. clutchc said:
    The standard pin-out for a Molex cable is:
    Pin Color Type
    Pin 1 Yellow +12 V
    Pin 2 Black Ground
    Pin 3 Black Ground
    Pin 4 Red +5 V

    You will want to connect the Molex's +12V (yel) to the fan's positive (+) wire, and the Molex's ground (blk) to the fan's negative (-) wire. If the fan has red, blk, and yel wires... they will be
    red (+)
    blk (-)
    yel (tach)

    Where should I connect the tach to? Should I just keep it closed and isulated?
  5. You won't use the tach. The fan will run at full RPM all the time when connected to the PSU. So, insulate it off with a butterfly of tape so it doesn't get into trouble.
  6. clutchc said:
    You won't use the tach. The fan will run at full RPM all the time when connected to the PSU. So, insulate it off with a butterfly of tape so it doesn't get into trouble.


    Thanks. I will do it tommorow and I'll post a pic :)
  7. clutchc said:
    You won't use the tach. The fan will run at full RPM all the time when connected to the PSU. So, insulate it off with a butterfly of tape so it doesn't get into trouble.

    http://www.mediafire.com/view/?yx41vmxeyh4d992
    Is this ok? Can I connect the white male molex to my psu?
  8. ril2 said:
    clutchc said:
    You won't use the tach. The fan will run at full RPM all the time when connected to the PSU. So, insulate it off with a butterfly of tape so it doesn't get into trouble.

    http://www.mediafire.com/view/?yx41vmxeyh4d992
    Is this ok? Can I connect the white male molex to my psu?


    Yes, that is correct. Do you have a voltmeter? You can verify by reading between the yel and blk wires on any Molex when the PSU is powered up if you want further confirmation.
  9. clutchc said:
    ril2 said:
    clutchc said:
    You won't use the tach. The fan will run at full RPM all the time when connected to the PSU. So, insulate it off with a butterfly of tape so it doesn't get into trouble.

    http://www.mediafire.com/view/?yx41vmxeyh4d992
    Is this ok? Can I connect the white male molex to my psu?


    Yes, that is correct. Do you have a voltmeter? You can verify by reading between the yel and blk wires on any Molex when the PSU is powered up if you want further confirmation.


    Thank you very much it works !!!!!
Ask a new question

Read More

Motherboards Cases Fan Connection Components