Noctua 4-pin PWM fan speed control

Jesus, you almost gave me a heard attack :wink:
Kind of harsh to do it online and not live.

Do you have an external 3.3V power supply? If yes…

please connect it like this (DON’T connect 6 to 3.3V, 7 to PD0 and 8 to PD2) and provide external 3.3V to 6 and 8. Don’ forget to connect the ground from your power supply to 1 or 3

and measure 5. 6, 7, and 8 to ground. Oh, and measure the external 3.3V source to ground.

Fan NOT running?