I have noticed that some problems are caused by the hotend fans. On the one hand, the fans whine strongly at lower speed and on the other hand, they only start to rotate at all at just under 40% speed setting. Below 40% they do nothing at all.
Are the fans defective or can it be corrected otherwise? I print a lot of ASA and would like the fans to run slowly.
Or is there a fan shroud for normal 40mm noctua fans?