FAN0 and FAN2 not working



  • I have a Duet 2 Wifi 1.04 since few month. I have a blower fan on FAN0 and a extruder fan on FAN1 and at the begining all work good.
    A time ago I remove and replug the fans, but the two are inverted. So I reverse the plug.
    I have replace the faulty fuse fan blade, and now the extruder fan work on FAN1 and Always On plug, but don't work on FAN0 and FAN2 (with M106 P0 H-1 S255 for FAN0).
    The blower fan don't work on any fan plug.

    I have to change the two MOSFET for FAN0 and FAN 2 ?
    I have a hot air station.



  • A wire on blower fan disconnected. After resoldering the fan work on fan1, but not on fan0 and fan1. I wait for new mosfet


  • administrators

    I'm glad you found the problem.

    When removing the old mosfets, you need to either shield the white plastic parts of the fan connectors from the hot air, or remove them temporarily. Otherwise the hot air will burn them. I heat them to 170C using hot air and then pull them off using pliers. After replacing and testing the mosfets, I heat the pins to 170C again and put the plastic parts back on.



  • I could put a PMV20XNE 7A for mosfet. It could be more stronger.


  • administrators

    @pipersw said in FAN0 and FAN2 not working:

    I could put a PMV20XNE 7A for mosfet. It could be more stronger.

    A quick glance of the datasheet suggests to me that PMV20XNE would indeed be a suitable replacement, with a higher maximum drain current.



  • Do you know why the mosfet for the fan are more subject to fail ? Current spike with inductance ?


  • administrators

    In typical use the fan mosfets are reliable. However, if a fan output is shorted, or the fan is connected the wrong way round, then a high current flows and the mosfet typically fails before the 1A fan fuse blows. Also, if a DC motor is connected to a fan output, then the starting current of the DC motor is typically higher than the 3.5A current rating of the mosfet. The mosfet may last for a while, but eventually fails.

    Brushless fans don't generate current spikes, and in any case revision 1.02 and later Duets have flyback diodes on board.



  • @dc42 said in FAN0 and FAN2 not working:

    PMV20XNE

    after change mosfet for the 3 fans with PMV20XNE, all work now !!


  • administrators

    @pipersw, I'm glad you got it working. We're looking at changing the fan mosfet type to AO3400A or PMV20NXER in future production runs.


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