Case and CPU Fan Question.

kenr77

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May 22, 2007
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I am about to build a system with a Centurion 5 CAC-T05-UW case, and was considering Zalman CNPS7700 CPU Fan. This fan looks like it will fit beneath the Cone Shaped side vent and either blow out or suck in from that vent, which as I say, has cone shaped attachment. One thing that bothers me is that the MoBo has a 4 pin CPU fan connector, the extra pin is for fan speed control and this and most other CPU fans I see only have a 3 pin connector. Why is this..??? Am I missing something here..??
 

millwright

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I haven't done much with computers for the last year, so maybe it is new, but I have never seen a 4 pin fan connector that had speed control on the 4th pin. the only 4 pin fan connector I have ever seen is the kind that plugs into a regular 4 pin power supply connector. these have 2 grounds a 12v and a 5v pin.Only the 12v pin and 1 ground are actually use.

Are you sure you are not looking at a Aux 12v power connector for the motherboard?
Speed control dosen't require an extra pin, because it is done by reducing the input voltage before it gets to the fan. The 3rd wire on a 3 wire connector, is for the tachometer.
 

kenr77

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May 22, 2007
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No I am not talking about the 4 pin 12v Aux connector, or any other PSU cable connector. Here is a cut and paste from the Manual.

JCFAN1: CPU Fan Header

__ JCFAN1

__ Pin
__ Assignment

__ 1 Ground
__ 2 +12V
__ 3 FAN RPM rate sense
__ 4 Smart Fan Control

Maybe it is a wire from the fan assembly itself. As suggesteed a wire from the Fan controller.??