# PWM Fan



## Drackyn (Jul 9, 2010)

I recently purchased the F12 Pro PWM fan from Arctic Cooling and it doesn't run at all in my computer. Now, I was under the impression that PWM fans - this is the first one I've tried hooking up - would just run at maximum speed if not supported or not hooked up properly. But I tried putting the fan in another computer and it ran fine.

My motherboard only has one four-pin slot so I had to remove the CPU plug and place it into a slot on the fan wire, then plug the fan into four-pin socket on my motherboard. I tried running it without PWM and with PWM (three-pin was hooked up and it was turned on in my BIOS), and in both cases the CPU fan would work but the Arctic fan wouldn't run at all.

The second computer also required hooking the CPU pin through the fan socket, but in this case both fans worked just fine.

The specs of my computer, the one in which the fan would not run at all, are as follows.

Motherboard: Gibabyte, GA-M57SLI-S4
CPU: AMD Athlon 64, 2.5ghz dual-core
Memory: 2gigs of Corsair ram.
Graphics Card: Asus 8600GTS
OS: Windows XP, service pack 3.

I'm not sure what the specs are of the second computer as it is not mine and I didn't build it. I just know that it was originally a pre-built, store bought unit that has been upgraded over the last year or two. It is currently running Vista.

Anyone know what would cause a fan to not run at all in my computer but work just fine in the other? I'd appreciate any help I could get.


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## hal8000 (Dec 23, 2006)

How many wires do you see from the fan and what colours?
If you see red and black then its a 12V fan and the PWM module is built into the fan.

You can use a multimeter set to 20V DC to measure the voltage across the connectors,
be exteremely careful and make sure that the probes NEVER touch, as there is massive amounts of current.

Hope that helps


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