Hi,
I was just wondering what the voltage output is of the SATA Hat’s 2-pin fan header?
My CPU fan seems to produce this weird clicking noise and quite frankly seems a bit small compared to other heatsinks I’ve got. I’d like to use the connect for my new fans but I’d just like to make sure its a 5V header before I start splicing cables 
Thanks,
Swindy
The cpu fan connects to the 3 pin header.
2 pin header is for RTC battery
I must have an older revision of the board because I have a 2 pin labelled “Fan”
Anyone know what the voltage for the header is? I’m assuming 5V
Just following up after getting out the multimeter, it is indeed 5V. But it is important to note that apparently newer boards have PWM fans
Well… a 3-wire fan isn’t exactly a PWM fan. The 3rd wire is a tacho output from the fan. PWM fans have 4 wires.
Next to that: it doesn’t seem the SATA hat nor the code uses in any way the tacho output from the fan.
From what I can tell from various posts here and in other places about PWM fans, it has 3 pins to actually control the PWM fan then the 4th pin is just a RPM pin, as you say. I’m planning on using a 4 pin Noctua fan to replace my stock fan, unless I can get it to quieten down in other ways
4-pin fan: has fixed 12V/5V, GND, TACHO and PWM. On the fan itself is logic present to controle the fan speed.
3-pin fan: PWM’d 12V/5V, GND, TACHO. The speed is externally controlled.
Tacho outputs are there to have an idea of true fan speed, compared to the requested fan speed. If delta is to large you can generate alarms or do something with the PWM pulses, or… whatever suits you best…
