weird sound print cooling fan at low %
I have my prusa MK3 for a week now. Prints great and really quiet. Except for the part cooling fan. Expecially on low % it makes this real annoying noise.
Anyone have an idea what to do?
yeah, that's due to the pulse width modulation of the power that drives the fan.
I've the same annoying sound here at my i3 MK2.5.
an easy way to suppress this noise should be to solder a 10µF or 22µF capacitor directly at the fan... and a diode in series of the supply. this should do the trick to convert the pulse width modulated supply voltage into a more steady analog value between 0 and 12V.
with the new R3/R7 extruder, where the print fan is mounted at an angle of 45°, it should be easy to get access directly to the joints where the two supply wires are soldered to and there should be enough space as well.
more elegant would be to fit a little "adapter" inside the electronics box.
I'm going to check this tomorrow evening and will post an image if it works the way I'm expecting it...