Noctua NF-F12PWM Case Fan does not spin itself

[rubez]

My exhaust fan does not spin. When I turn the computer on, every 2 seconds or so it tries to spin, but it's as if there isn't enough power to get it going initially. It just moves a tiny bit, stops, then keeps repeating that - like when you stop a fan by force - it will keep trying to restart by itself.

If I give it a helping hand and spin it manually, it will happily spin fine from then on, but wont start if I reboot.

Nothing is obstructing it, I don't think there is anything wrong with the fans...

I have it plugged into SYS_FAN1. I heard that this particular fan spins slower than other fans.

Does anyone have a clue what is going on here?

Thanks.

 

[ahnilated]

Replace the fan.

 

[rubez]

It is brand new, this is a new build I should have said.

Some sort of BIOS setting?

 

[ahnilated]

Nope, the fan is not spinning up, it is either bound up or bad, replace it.

 

[rubez]

I think you are wrong. I don't think it is getting enough voltage somehow. When I go into BIOS and change system fan 1 to full speed, it starts every time after rebooting and cold boot.

I change it back to normal and the fan wont start.

Options are normal (default), silent, manual and full speed.

I would like it to be as quiet as possible, until it detects it is getting too hot and ramps up the speed. When I choose manual, there is no value or anything to choose.

Any ideas?

 

[rubez]

Sorry, I mucked the title up, it is not the NH-U12S that doesn't spin (that is the fan strapped to my Noctua heatsink)

It is a Noctua NF-F12PWM Case Fan 120 mm.

Don't know if that makes a difference (have changed the title)

The notes for the fan say:

"The NF-F12 comes with a 4-pin PWM fan connector for fully automatic speed control via your mainboard's 4-pin PWM fan headers" (which I am using) "Please note that the fan can also be connected to your mainbard's 3-pin fan headers though. When connected to 3-pin fan headers, the NF-F12 will run at full speed (unless the mainboard supports voltage based speed control)"

Maybe I could use this method so the fan always starts, and if I have voltage based speed control on my motherboard, it will slow down from full speed?

 

[rubez]

http://www.noctua.at/main.php?show=faqs&step=2&products_id=42&lng=fr#11

or

from mobo pdf:

CPU Fan Speed Control (CPU_FAN Connector)
Allows you to determine whether to enable the fan speed control function and adjust the fan speed.
Normal Allows the fan to run at different speeds according to the CPU temperature. You can
adjust the fan speed with EasyTune based on your system requirements. (Default)
Silent Allows the fan to run at slow speeds.
Manual Allows you to control the fan speed under

maybe temp too low to warrant spinning?

when I change it to silent, the fan doesn't even bother twitching. just dead stopped.

 

[rubez]

I think I found the problem.

Basically pin 4 (on motherboard) is not being used for speed control.

from Noctua site:

Note that mainboard manufacturers use different terms to indicate that Pin 4 is not being used for PWM control (e.g. “+5V”, “VCC” or “NC”), but if one of these terms is used, you can be sure that the fan header does not support PWM. If Pin 4 is described as “Speed Control” or “PWM” or the like, you can be sure that the fan header supports PWM.

To resolve the issue, you can:

Choose a higher fan speed profile in the BIOS (e.g. „normal“ instead of „silent“, etc.) or deactivate automatic fan speed control and use a Low-Noise Adaptor instead.

Use the mainboard‘s fan speed control software or 3rd party tools like Speedfan to regulate the fan speed. Unlike BIOS based fan speed control, the supplied software usually checks whether the fan has stopped and increases voltage accordingly or at least offer more options to set up the fan properly.

If your mainboard features other 4-pin fan headers that use PWM for speed control, you can run multiple fans from these headers using Y-split cables. Make sure not to exceed the specified maximum power draw of the fan headers (usually 10-12W) though.

from motherboard manual:

SYS_FAN1/2/3
Pin No. Definition
1 GND
2 +12V/Speed Control
3 Sense
4 VCC