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X Axis limit switch not working


I have installed the mini gerbil without a hitch into the k40.

When I home the machine Y homes and stops but X crashes into the stop and grinds away. I have to power the machine off

Limit switch is the 4 wire

Plugged the original board n2 board in and work fine. Yep double checked.

Any ideas?



Hi Das,

Check the 4 wires sequence and see if they correspond with the connector layout on the Mini Gerbil (see attached photo). You can check also the status of the limit switches (engaged or not) via the command ? (question mark). Just type this ? into the LightBurn or G-code sender's console. You should see something like Pn:XY if the switches are activated. Just drag the gantry in the left top corner and and see what info you get. You can remove the X stepper driver if that motor keeps crashing and you want to prevent that. Let me know what you found and we decide our next step if necessary.


Uploaded files:
  • MGLimitswitches.PNG
Cheers, Paul awesome.tech


Checked with ? And I get Pn:Y

I have the mini gerbil that uses the ribbon.

Miltimeter is in the car, check will theck tomorrow.



Uploaded files:
  • IMG_20190522_220156.jpg
  • IMG_20190522_215155.jpg

Hi, did you find the solution to your problem?

Limit switch errors can be tricky but some common errors:

  • Crossed wiring GND-GND has a switch and Y-X has a switch
  • Broken wire
  • Loose connection
  • Broken switch
  • Pull Off (On/Off hysteresis is bigger than default $27=2.5 (make it 4mm)

Best way to test is:

1. Manually park Y or X axis in the home position and interrogate the controller via the Question mark (? <enter>). Status should show Pn:Y or X

2. Park the gantry in the middle of the machine and repeat the interrogation. Status does not show Pn:X or Y

3. Repeat for the other axis.

If the limit switch axis are reversed than swap X and Y limit connections.

If the limit switch is inverted than set $5 ($5=1 if X is inverted, $5=2 if Y is inverted or $5=3 if both X and Y are inverted)

Hope this is helpful to debug limits.

Uploaded files:
  • XYLimitsError.jpg
Cheers, Paul awesome.tech

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