PWM throttle hack

why | how | photo love story | background on pwm fans


The other day I bought this shiny new mainbord, a CPU and a CPU fan, which support cool and quiet and what happens?
Right: It Don't Work!
The cpufan howls like a storm once the bios kicks in.
This feature is called "CPU Quiet Fan".


In order to fix this I disabled the feature in the bios so the fan runs at maximum speed.
Then I hijacked the pulse line and fed this and a 5V line from a power cable to the fan and TADA: silence.


The initial setup:

left: the cpu fan cable
right: an audiocable I connected to the mainboards cpu fan socket
top: a power cable - the red one has 5V, the black ones are ground and the yellow one has 12V


I used tinker wire because I had nothing else at hand..


Nicely packaged with insulating tape =)

The downside

I am not responsible for any damages blah blah.. think before you act and don't bug me if it breaks.
The bios doesn't recognize the fanspeed anymore - I suspect it is because it expects a 12V signal. In my setup I just left that pin empty to avoid possible trouble.

Background Description of the PWM Socket