Connecting 4 wire CPU fan with ATX power supply

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Chemical Cyborg

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Jun 21, 2015
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Hello,
I have a Alpine 11 GT REv.2 CPU cooling fan with a 4 wire connections (Red, black, Yellow and blue). I am trying to connect the fan with a standard ATX power supply. I have connected the red and the black wire with the positive 12 volts and GND respectively and left Yellow and blue open, however the fan is not working. Can some one please help me?
 
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P
I want to check the ORDER of the wire colors on your fan connector. On a 4-pin fan, one common color coding is:
Pin #1 - Black: Ground
Pin #2 - Red: +12VDC
Pin #3 - Yellow: Speed pulse signal back to mobo
Pin #4 - Blue: PWM signal.
Since you are attempting to connect to a PSU output connector, you should not connect anything to Pins 3 (Yellow) and 4 (Blue).

Now, on a standard 4-pin Molex output connector from a PSU, the color coding is:
Pin #1 - Yellow:+12 VDC
Pin #2 - Black: Ground
Pin #3 - Black: Ground
Pin #3 - Red: +5VDC

You are correct to connect fan Black to Molex Black. However, fan Red needs to be connected to Molex Yellow. I suspect you have connected it to the Red on the Molex, which would give your fan 5 VDC. Often that is...
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Vic 40

Vic 40

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Oct 22, 2013
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Why not try an adapter? 3pin->molex for instance.Would make the cooler run full rpm,but your way too.
Why not use a different header on the motherboard?

The psu fan is working? So you connected the green and a black wire? On the 24pin that is.
 
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Chemical Cyborg

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Jun 21, 2015
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Hi Vic 40, Many thanks for your reply. The PSU is working fine, its fan is working and I have sorted the green and the black wire to run the PSU. I haven't tried the adapter though, but I have connected the red and the black wire into the molex pins. Do I have to do some more connections to the yellow and black wire?
Thanks!
 
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Paperdoc

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Oct 19, 2006
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I want to check the ORDER of the wire colors on your fan connector. On a 4-pin fan, one common color coding is:
Pin #1 - Black: Ground
Pin #2 - Red: +12VDC
Pin #3 - Yellow: Speed pulse signal back to mobo
Pin #4 - Blue: PWM signal.
Since you are attempting to connect to a PSU output connector, you should not connect anything to Pins 3 (Yellow) and 4 (Blue).

Now, on a standard 4-pin Molex output connector from a PSU, the color coding is:
Pin #1 - Yellow:+12 VDC
Pin #2 - Black: Ground
Pin #3 - Black: Ground
Pin #3 - Red: +5VDC

You are correct to connect fan Black to Molex Black. However, fan Red needs to be connected to Molex Yellow. I suspect you have connected it to the Red on the Molex, which would give your fan 5 VDC. Often that is not enough to start the fan up, although it may be enough to keep it running at very low speed (but risk stalling).
 
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