On mainboard rev. 2.1.4 it is controlled via a transistor connected to the atmega pin PJ6 (integrated in the circuit).
On rev. 2.1.1 it is directly connected to 5v without any way to control it.
If you have the old revision and if you are keen on modifying the firmware and a little soldering you can buy a BC817, a 1k resistor and a diode (a small 1n4148 or similar will do), and build a little pin driver (just like the one for the cooling fans and LED stripes) and move the fan ground to the transistor and connect everything (for easy access) to pin 3 of the EXP3 header (which is the atmega PB7 pin, which is PWM capable).
You should not directly connect the fan to PB7 as it would exceed the power delivery capabilities of that pin (the fan can easily draw 100mA which is way to much for any atmega pin).
Edited by Guest
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00D00B 58
Hi,
On the new motherboard rev, the J34 pin (Fan 5V in which the fan is connected) is actually powered on only when the nozzle temperature reaches 45 degrees but I think it's a new hardware addon ?
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