I just put a new MK8 extruder and stepper on my Prusa i3, the
extruder it replaced was also a MK8 but didn't have the cooling fan on the extruder drive.
It had the one for the print cooling fan but not the other.
My question is when should that fan be running, 12v from the P/S
or the fan drive from the Melzi board that drives the print cooling fan.
Forgive me if this is the worng area to post this question.