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Fans stay on at full speed - M107, M106 S0 not working

Discussion in 'Troubleshooting' started by Matt Zarkos, Sep 3, 2019.

  1. Matt Zarkos

    Matt Zarkos New Member

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    Anyone having problems turning the cooling fans off or adjusting their speed? The M107 (fan off) command isn't working for me, nor the M106 S0. I've tried different P values with no success and also turning off cooling in Cura and making sure M107 is active in the start up gcode script. I've started unplugging the left fan and prints are more or less OK, but the fan noise is awful!

    Any suggestions appreciated -

    Thanks
     
  2. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    R1 printer?
    Not sure what left fan means for the R1 -- parts cooling fan or extruder fan?
     
  3. Matt Zarkos

    Matt Zarkos New Member

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    <sigh> sorry about that. It's an R2. I hit the "post your problem in the troubleshooting forum" button not seeing I was in the R1 one. Not seeing any option to delete or move the thread.
     
  4. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    I have not tried adjusting them from full-speed myself (on a C2).
    You could try swapping them for some quieter fans (if Noctua makes fans that size then that is the brand I'd switch to).

    I am not sure which output those fans are even wired to on the Robo control board -- it may or may not be a PWM controllable output. I'd say that is less likely than certain because they pretty much cloned the Arduino Mega+RAMPS 1.4 electronics in their control board (but that doesn't mean it is identical).

    This sort-of implies they are controllable though:

    https://help.robo3d.com/hc/en-us/articles/115000716671-Cooling
     
    #4 mark tomlinson, Sep 4, 2019
    Last edited: Sep 4, 2019
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  5. Matt Zarkos

    Matt Zarkos New Member

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    Thanks Mark - yes, documentation (in several locations) seems to support fan control, which makes it all the more puzzling/frustrating. The RAMPS board is otherwise working fine. I'm getting a suspicion that this may end up being something like case lighting, where a resistor has to be removed to make it controllable.

    Noctua seems to get high praise for quietness - I'll check them out. Looks like right size available, I'll just need to check voltage at fan. I appreciate the tip!

    I'm curious, do your fans start when the printer is powered on and then stay on until printer power down?
     
  6. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    No, the fans do not start with printer, they come on when the hotend is heated/heating AND printing.
    The center fan (for the hotend) is always on, but not the two parts cooling fans.
     
  7. tkoco

    tkoco Administrator
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    A bit of insight about the fans: the RAMPS / ROBO board sends +12 volts to all fans via the Uptown / Downtown PCBs. The difference between the hot-end cooling fan and the parts cooling fans lies in the return power lines of the fans. The hot-end cooling fan is wired directly to the 12 power return line. The return power lines of the parts cooling fans are PWM controlled by the RAMPS /ROBO board. Those return lines are wired together on the Uptown PCB before the wiring goes downstairs via the wide ribbon cable to the RAMPS /ROBO board.

    For pin-out information, check out the following thread in this same forum: ROBO R2 Uptown board
     
  8. Matt Zarkos

    Matt Zarkos New Member

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    Thanks tkoco - connections haven't changed so I'm thinking there's some kind of short or bad PWM pin connection. I pulled the connector from the uptown board to the main motherboard and the lines for the part cooling fans are on all the time, regardless of what commands are sent. At least it didn't break and kill the voltage! I've unplugged one of the fans to tone down the cooling.
     
    #8 Matt Zarkos, Sep 9, 2019
    Last edited: Sep 9, 2019
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  9. tkoco

    tkoco Administrator
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    Before you use this mitigation effort, have a look at the downtown PCB connections of the cooling fans. They should be plugged in like this:

    [ 3 black wires ] [ parts fan ] [ hot-end fan ] [ parts fan ]
     
  10. Matt Zarkos

    Matt Zarkos New Member

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    Thanks - all in their correct places. In dissecting the connections I saw they had the capability for controlling the parts fans separately, but chose to short the two together on the uptown PCB.

    Ultimately I'm planning to switch to an unused PWM pin available on the motherboard, but that's a project for another day.
     
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