PWM fan not stopping

  • Hi,

    I just installed the model cooling fan and connected it to one of the PWM slots.

    When I start up the board the fan is off, but as soon as I turn it on once it never stops completely. Also when I print and the fan shouldn't spin for the first few layers it still spins, not on full power but on ca 10-20%. When I command M106 P1 S0 directly it also doesn't stop.

    One thing i have to mention here because it might be related is that I managed to blow up the PMW0 slot. I don't know how I did it. I had it connected to a board cooling fan and was running it normally for some hours and all of a sudden I heard a "clack" and the fan turns off. The fan is fine and works on other slots but the plug/slot doesn't work anymore.

    The other PWM slots still work though.

    Any ideas on how to turn the fan off completely? and also on how to prevent more slots from blowing up? 😄


  • I noticed that the thermostatic control influences the behavior.

    So under 45C the fan turns off, but how do I contruct the M106 command to not always be on above 45c without loosing the thermostatic control?

  • I'm a bit confused as to what you are trying to do here. If it's a part cooling fan, one wouldn't normally run that in thermostatic mode. In order to run it in thermostatic mode, you need to monitor a temperature and I can't see how you could measure the temperature of the part you are trying to cool. Is it a "model cooling fan" as you say, or is it in fact the hot end fan that you are trying to set up? It's probably best if you could post the sections of your config.g that are relevant to fans and heaters as well as a bit more detail on how you have done the wiring.

  • Use M106 Px H-1 to turn termostatic mode off-

  • Yeah, youre right, I dont know what I wanted the model cooling fan temp controlled.

    Any ideas on the cause of how the FAN0 slot got blown up?


Looks like your connection to Duet3D was lost, please wait while we try to reconnect.