Noctua Case Fan Issue

[rrevan]

Hello guys

I have an issue and i need your help to solve it

I recently purchased 2 Noctua NF-S12B redux-1200 PWM fans.

I use them on a Gigabyte H87-D3H motherboard, which has 3 PWM conectors available for system fans.

I use one fan for exahust, on the back of the case, conected to sys_fan1 port, and its working perfecty. But my second fan, positioned in front of the case for intake, refuses to work...it twiches every 2 seconds, like it wants to start but has no power. I tried to conect it to both sys_fan2 and sys_fan 3 ports, with same result.

I checked every sys_fan port with the working fan, and they all work perfectly. So, i assumed the second fan is faulty, and i was about to RMA it.

But then, i unplugged the first fan, and connected the second one, which i thought its broken, and surprise....it works.

So, the motherboard conectors are fine, both fan are ok, but they just refuse to work at the same time. If i connect only one at the time, they work fine. When i connect them both, the one i connect secondly, just twitches.


Do you have any ideea what is the issue? I assume it is a BIOS setting. I tried and reseted the BIOS, and the problem seemed to be solved. But after few hours, when i rebooted, same thing happening again.



Please help.


bellow is a link with a pic with my BIOS fan settings:

http://

 

[n0ns3ns3]

are your fans PWM or regular (4pins connector vs 3pins) ?

 

[rrevan]

They are PWM

 

[n0ns3ns3]

what happens if you set them to 100% ?

 

[rrevan]

How do i set to 100?

I did change in bios to manual setting and set the highest rpm/degree and still nothing.

however, i noticed that while it twiches, if i push the fan a bit, give it a spin, then it starts working, and keeps doing so untill reboot.

 

[rrevan]

I also installed the APP Center from Gigabyte, and tried to use the fan control software provided...but, its the same problem. Once i shutdown the computer, when i power it on , the fan just twiches.

 

[n0ns3ns3]

the voltage required to start the fan is different between different models.
For example, i have noctua fan connected to a manual fan controller (all non PWM with knobs ). so in order to start the fan, i have to set higher spin, and than turn it down to whatever i want. otherwise the fan will not spin.
So it might be that the problematic fan requires a bit more or/and the non CPU headers provide a bit less. it is really hard to tell which one is faulty.
Can you try to change the headers control to non PWM mode in bios, and than set them to 80-100% and see the change ?

 

[rrevan]

I looked everywhere in bios and i cant find where to turn the pwm mode on/off 🙁

 

[n0ns3ns3]

in the first post, you have a screenshot of the BIOS,
there are " <fan header name> Fan Speed Control" rows with "normal" values.
what are the other values ?

 

[rrevan]

The other values are Silent, Manual and Full Speed

If i choose Manual mode, i can then change PWM/ celsius degree ratio by 0.25, up to 2,50 PWM/degree

 

[rrevan]

Like i said, i have gigabyte Appcenter installed, and if i acces SIV application from it, i can see 2 tabs for fans control.

And, when my fan is twitching, if i go there and set fans to full speed, it starts to spin, and then if i revert it down to regular speed, it continues to work....

i just dont understand what's wrong with it

 

[n0ns3ns3]

hmm ...
Seems like gygabite saved a cent or two. Asus boards can control both PWM and non PWM fans on the 4 pins headers.
Anyway, I went through the thread again and it seems like the MB is the problem since it can handle only 1 fan properly.
Assuming you already updated the BIOS to the latest version (F10), you can:
1. do this "full speed procedure" manually every boot.
2. buy a PWM fan hub like those two below:
https://www.amazon.com/SilverStone-System-Cables-Black-CPF04/dp/B00VNW556I/ref=sr_1_1?ie=UTF8&qid=1474818994&sr=8-1&keywords=silverstone+fan+hub
https://www.amazon.com/Swiftech-8W-PWM-SPL-ST-Way-PWM-Splitter-Sata/dp/B00IF6R4C8/ref=sr_1_1?ie=UTF8&qid=1474819111&sr=8-1&keywords=swiftech+fan+hub
the downside of using those hubs is that all fans will be running at the same speed - they can not be controlled individually.

 

[rrevan]

Yes...i did some digging around, and it seem that Gigabyte lied a bit in theier description of the product.

From what i see, the mb offers PWm support only for the CPU, and for the case fans only some kind of voltage control...

I am not sure, so here are the facts:

from mb manual, here is the description of fans conectors

http://postimg.org/image/hm2oxvko3/



And from Noctua website, here is a quote:


"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.

Unfortunately, the description of Pin 2 is not always a clear indication as some manufacturers use terms such as “Fan PWR” or “Power” for both types of fan headers. However, if Pin 2 is described as “Speed Control”, you can also be sure that the fan header does not support PWM based speed control. If Pin 2 is described as “+12V”, this is a clear indication that the fan header supports PWM.

Please also note that in some cases, the descriptions of the pin layouts in the mainboard manuals may not be correct and some models actually allow you to switch the fan headers from voltage control mode to PWM control mode in the BIOS even though the pin descriptions do not indicate PWM support. We thus recommend to look for these options in the BIOS before taking other measures. In case of doubt, please contact your mainboard manufacturer."


So, if i am not mistaken, those 4 pins headers from my mb, do not offer PWM control...




If this is the case, then the problem is i have 2 PWM fans conected to non PWM headers....will that explain why one of it just twitches?

If so, shall i use speedfan? This gigabyte softaware looks kinda crappy....or should i just return the fans and buy non-pwm ones..

 

[n0ns3ns3]

there are two ways to control the fan speed.
PWM - using pulse width modulation and the voltage is always 12V
non PWM - reducing the voltage.
As I explained earlier, fans require certain amount of voltage to start. the PWM fan is expecting to get 12V. so when you trying to control it with voltage, it receives less. If you set it to "full speed" it receives 12V. A good non PWM fan controller will do a spike of full voltage to start the fan and than lower it to match the settings. That's why in some systems you can hear fans spinning at full speed for few seconds when computer is turned on.
You can try to play with settings and find the minimum level it will start.
You can try to use speedfan if it will work with your motherboard, but that will not change the MB.
I'd use one of those hubs (connect it to CPU fan header) or just a simple PWM spliter like this one:
https://www.amazon.com/Sizet-Splitter-Computer-Power-Cable/dp/B01IR145RM/ref=sr_1_2?s=pc&ie=UTF8&qid=1474821859&sr=1-2&keywords=PWM+Fan+Splitter+Cable

 

[rrevan]

Thank you for your help

 

[n0ns3ns3]

you are welcome