Fan problem help needed

[artus]

I have just finished building my new system turned it on and boots fine apart from the 3 front case fans will not spin up system is a 5820k on a X99A SLI krait Edition in a corsair 540.

The rear fan is working no problems there connected to sysfan3 the 2 fans on my h100 are fine too connected to CPUfan2 with a a splitter. The 3 front fans were connected to sysfan1 with a 3 way pwm splitter they would twitch and if I helped them they would start spinning but they are not being detected in the bios where as the exhaust fan and rad fans are.

Tried a single fan with the same results on sysfan1 and 2 am I right in thinking there is not enough voltage ? and would a powered pwm splitter solve the problem? .

 

[Bart_Hunt]

I guess its a voltage.
Get a Phobia 3x4 pin splitter, molex powered.
It should have a cable to connect to motherboard too.

 

[Tealc]

Check your motherboard manual for PWM allocation to fan headers. Not all headers will support PWM output, some having no connection on pin 4, the all important PWm signal pin.

If pin 4 of SYSFAN 1 or SYSFAN 2 are NC or No Connection then only voltage control will work with those headers.

PWM fans require generally higher voltage than 3 pin fans to start spinning so you need to either use a different header, different fans or raise the linear fan control curve in BIOS.