Re: Prusa i3: no homing after activation of second fan

H_T — Mon, 19 Jan 2015 05:28:27 -0500

I worked around this by plugging the fan into the 12 V power supply on the board.

Prusa i3: no homing after activation of second fan

H_T — Thu, 15 Jan 2015 07:57:03 -0500

Hi,
i have a Prusa i3 with Megatronics 3.0 electronics. Firmware is Marlin 1.0.0.
I adapted some values for speed and acceleration in configuration.h, everything works so far.
Due to very hot stepper drivers I activated Fan2 by inserting the following after line 1140 in Marlin_main.cpp as suggested in [reprap.org] (bottom):

       for(int8_t i=0; i < NUM_AXIS; i++) {
        destination = current_position;
      }

//beginning of insertion
       #if FAN2_PIN > -1
     case 806: //M806 Fan2 On
       if (code_seen('S')){
       analogWrite(6, constrain(code_value(),0,255));} //D6 is fan2_pin as in pins.h
       else {
         analogWrite(6, 255);}
       break;
     case 807: //M807 Fan2 Off
       analogWrite(6, 0);
       break;
   #endif //FAN2_PIN
//end of insertion

      feedrate = 0.0;

#ifdef DELTA

Turning the Fan2 off and on works, but homing doesn't work anymore. I can move the axes, everything else seems to work, except homing.

Does anyone have an idea what to do?

Thanks!

Edit: Could I use the 12 V output on the board to connect the fan? It would be constantly running but I wouldn't mind. I'm not sure what current it supports though.