RADDS fans: M106 P1 doesn't activate the attached fan

First, some background information:

RADDS + DUE in a FlashForge Dreamer body + a 3-in-1-out Extruder (only using one extruder at the moment) + Repetier 1.0.1dev.

Fans were initially connected to D8 and D9 and, at one point, worked (M106 commands and thermocouple sensing worked). Recently, the fans were always on, so I investigated.  I saw that the associated MOSFETs might be broken (always on, confirmed with multimeter and the two bright LEDs shining at my face).  I tried a test sketch that cycled through the MOSFETs and confirmed that they are stuck on.  So, I will replace those.  The fans were then moved to D11 and D12, which are unused.

When I configured the firmware, I specifically indicated D11 and D12, not the Fan/Fan2 pins.  This was confirmed in configuration.h.

The D11 (parts cooling fan) does work with M106 P0 Sxxx and Simplify3D's fan slider.  Voltage at S255 = 24v.  The associated LED lights up brightly.
The D12 (extruder) fan does not work.  Voltage at S0=370mV, S255=380mV.  The LED just barely lights up (you have to look really hard to see it).

Hardware Testing (without Repetier firmware):
D11 and D12 work with the test sketch, which sets the pins to OUTPUT and DigitalWrites them HIGH for 1 second.  Voltage for both MOSFETs go to 24V, the fans spin and the LEDs light up.

Software Testing:
As a test, I modified setFan2SpeedDirectly to *just* set D12 to OUTPUT/HIGH.  When M106 P1 S255 is executed, the LED flashes brightly and then immediately drops.

Looking at commands.cpp, it looks like M106 has changed since previous versions.

I'm going to check 1.0 and, if necessary, go back a version.


  • Update: I changed my configuration to not recognize M106 commands for Fan2 and just left it coupled to T0.  The same configuration.h worked in 1.0.1 and 1.0.1dev.
  • If fan 2 is defined in extruder as cooling fan you can not control it with M106. It gets controlle dby extruder temperature. If you defined it twice as cooling fan and for fan 2 they will disturb each other.
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