Z-homing no endstop hit


after installing the Repetier firmware 0.9.2 to my RUMBA board I had the following problem:
X and Y homing work fine, as expected. In Z - homing the printhead only moves a short distance (about 5 mm) towards the optical endstop, but does not hit it, if the start distance had been more.
I experimented with all possible combinations of endstop setups, but no success.

Falling back to Marlin Firmware there are no problems.
So there should not be cross talk effects.

Nevertheless i would prefer the Repetier firmware, because it supports the new CYCLOPS (dual extruder with 1 nozzle/heater) from E3D. Marlin does not support this feature yet.

Could anyone give a hint?



  • Homing moves 2 * zLength. If that is only a few mm you have either set steps per mm for z wrong (check eeprom) or z length is wrong.
  • Thank you for the quick response.

    The problem has been fixed.
    The motor- and endstop cables had not been drilled.
    After drilling the cables the z-homing procedure works as wanted.

    The endstop must have been triggered early by crosstalk.
    At first I did not assume this to be the reason, for Marlin did not have problems with it.

    Now I am happy to try the Repetier Firmware.


  • What exactly is "endstop cables had not been drilled"???

    What dose it mean driiling a cable?
  • If you have 2 wires it is not good to have them laying loosely side by side. Currents in one cable can cause current in the other by induction. So having endstop parallel to motor can cause endstop wires to send signals over endstop wire from this. If you drill the cables, this effect strongly reduces. If you have ever seen network cable you would know they also drill 2 wires belonging together inside the cable. Same reason.

    Easiest way to drill is fix one end and put loose end in drilling machine and turn 100 times. Then you have a drilled cable. But please drill motor separately from sensors.
  • Ahhh :-)

    I beleave the tecnical term is "twisting pairs".

    But I understand whare "Drilling the cabels" is comming from :-)

    Is it also recommended to "drill" the motor cabels?

  • Yes. It are the motor cables or extruder heater cables where the problem originally comes from.

    And yes, i remember having heard twisted pair of cables, so I guess it is the better term if one knows it :-)
  • Just a correction. The Marlin support the Cyplops hotend. Look for a Marlin Mago Kimbra. There are a lot of options. But i preffer the Repetier firmware too... q=)
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