replacing original MK3 cooling fan (5v) with a 12v fan
is it practical and/or safe to use a 12v cooling fan in place of the 5v fan or will that create damage to the circuit board? Is there a difference is fan speed between the default 5v fan and (if a 12v fan is safe to use) 12v fan's rpm's?
RE: replacing original MK3 cooling fan (5v) with a 12v fan
You cant expect to fit a 12v fan on to circuitry that is designed to work with a 5v fan and expect the 12v fan to work correctly. The voltage is far too low to spin it to proper speed and at low pwm values it might not spin up at all.
There would also potentially be some minor risk to the electronics of the drive board (ie your main printer electronics) depending on how its designed and what spec components are used to drive the existing fan as the 12v could be trying to draw more current too.
Normally it would be required to fit a separate mosfet transistor supplied by the 12v psu inputs and just take the logic level drive signal from the existing mosfet and feed it to the new one. Fromm there you would feed it to the wiring for the new fan. Not something I would recommend unless you are familiar with board rework and have a reasonable soldering iron setup.
There is also the fact that prusa fans have a tacho wire back to the electronics that the board uses to monitor the speed of the fan. That sense wire circuitry is also designed for a 5v return signal which a 12v fan is not going to have which further complicates matters. You would have to drop the voltage level on that too, without impacting the timing of the sense signal so that the board can correctly interpret the feedback and not trigger a fan failure alarm.
RE: replacing original MK3 cooling fan (5v) with a 12v fan
@neophyl
Thank you for your prompt reply. And, for making the technical aspect understandable.
Stay safe!