Hook up PSU fan for CPU cooler wiring dilemma.

[moon111]

I've built a custom shroud to put a 14cm fan on my CPU cooler. I have a 14 cm fan from a DOA PSU. The thing has two sets of wires. Both are two pin, one's red/black the other yellow/black. Any way this can be used to plug into the CPU FAN socket on my motherboard?

 

[Rory Buszka]

I think you can tie the two black wires together (ground), and then splice the yellow, black, and red wires into the corresponding wires on a three-pin connector. Red is power, black is ground, and then the yellow wire is the RPM feedback, usually negatively pulled-up (that is, a circuit sends positive voltage through the yellow wire to ground, and when it measures a current, it knows it's gone through a revolution). You can cannibalize a three-pin extension cable -- that's what I did in my own machine. the extra PCB from the PSU isn't necessary-- it's just an automatic thermal speed control circuit, most likely.

Disclaimer: I don't guarantee that you won't smoke anything by following my suggestions. But that's the risk you take whenever you try to mod something to fill a different purpose than that for which it was originally intended.

 

[Greg King]

I do not accept your picture. Please edit it and poorly draw out text in MS Paint.

I think MadMat is your man for answers on this one. Not that Rory is wrong, but I know for sure that Matt could answer this with absolute certainty.

 

[Rory Buszka]

Well, what I explained was simply what I'd do based on my own knowledge. I'm reasonably sure that it would work, because I think the two black wires both represent 'ground', so the color coding scheme is exactly like a typical 3-wire, RPM-monitoring fan.

 

[madmat]

Taterworks is 100% correct in that the red is power, the black(s) are ground and the yellow is RPM. The PSU that fan was pulled from either had PSU RPM monitoring or it was an option from the OEM and to save time and stock complexity they used that same fan irregardless of whether or not the people they were making the PSU for opted for RPM monitoring.

 

[moon111]

Thanks for the help! This isn't the only forum I posted this in, but it's the one that helped. So once again thank you. This project actually started this some time ago, but hit this obstacle and put it off. Once finished I'll try and post some pictures of the finished product.