Homing: Strange Beghaviour and Sound


I am using an IDEX setup with Repetier Server and Repetier Firmware on a RUMBA Board.
I am observing a strange behaviour when homing X-Axis since few days. With IDEX I always had the issue, that both X-carriages are homing twice. I found that thread, but changing to ZYX homing order did not solve it. I did not bother.

But since a few days, my printer is also "screaming" between the X-homing moves. I think it came with a firmware change. I was changing the Z-probe (from BLTouch to an inductive sensor). I also changed to Repetier Server Pro at the same time and uploaded firmware through Repetier Server Pro for the first time. So it is hard to say, where exactly it came from. Here is a short video.

The "screaming" not only happens when controlling it through the server but also when I start homing through the LCD-Panel.

Unfortunately I can not say, where exactly the sound comes from. I think it is from one of the X-axis motors. But not 100% sure. Everything else works fine, but i am a bit concerned, as it does not sound very healthy...

Any ideas?

Kind regards


  • Ok first it is a pure firmware issue. Nothing server related. Homing is completely firmware internal.

    The screaming are lost steps. It looks like it homes Z then Y and then twice X for some reason. I think it is the right extruder causing it. Happens when the end stop does not get triggered. Could it be that you hit the right end before the end stop safely triggers? Second try it works so to me it looks like it is on the edge sometimes working and sometimes not.

    What happens if you explicitly send
    G28 X0
    to only home x? Still twice? What when you repeat? Still twice? In the code I could not detect a reason why it happens twice. I only see one homeXAxis in order ZYX case.

    BTW: Why homing z first? I'd do it last so you are already parked in case you have forgotten some models on bed. So home XYZ would be my preferred homing sequence.

  • Hi,

    I checked a few things:

    - I definitely do not hit the right End before the Endstop triggers
    - With only homing X, i have the same behaviour (homing left extruder, homing right extruder, screaming, homing left again, homing right again). When I repeat homing, I still get the same.

    - I checked endstop wireing and function (With M119) - ok.
    - I changed homing order to XYZ - no difference
    - I increased ENDSTOP_X_BACK_MOVE and ENDSTOP_X_BACK_ON_HOME - no difference
    - I slowed down Homing speed (from 50 to 5 mm/s) - no difference

    any further Ideas?

    PS: What I did non mention: I have "#define LAZY_DUAL_X_AXIS 1" in the manual additions. Could it have to do with that?


  • OK, solved the issue with homing by disabeling LAZY DUAL X AXIS. I Use DUAL X AXIS MODE 1 and M606 for parking now. Thank you for your support!

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