Z Zero Touch Plate Issue

My apologies if this is covered elsewhere in the forum. I recently purchased a complete LowRider2 kit from V1 and just finished up my first build with serial wiring on the Rambo 1.4 card (pre flashed for CNC). Everything is appears functioning properly except when I attempt to zero the Z axis using a touch plate. The Z access descends to the probe then raises to the programed height before stopping, however once stops the stepper motor hums for a few seconds followed by this message displayed on the LCD.

Homing Failed:
Printer Halted
Please Reset

Any advice would be greatly appreciated.

Make sure you are plugged into Signal and Ground. Looks like you have the power pin involved which could potentially damage the board.

Signal to the plate, ground to the tool.

Thanks Ryan,

Here’s a couple picks of how the Z Probe is currently hooked up to the board. Hoping you could take a look before I start moving things around. This is a Christmas gift for my 15-year-old son so I would hate to mess it up now. Everything else seems to work and it cuts good.

What spindle do you have? Lots of the cheapie 52mm silver motor with power supplies with a clamp on collet seem to have a current leak and mess things up.

The stepper should also be homing the Z twice. It goes down once kinda fast until it touches, up , then down again really slow. It has to touch twice.

I bought a new Dewalt 611 just for this build and it’s not connected to the board in anyway. The z Axis goes and down touches the probe, then up, then a few seconds of humming and the error code.

Here’s my setup and a test cut.


I looked at where the “Homing Failed” message gets generated in Marlin. The comment near the line is:

// If the last move failed to trigger an endstop, call kill

This implies that the message is generated when the retest fails for some reason. This fits with your described behavior. Not sure what that means in terms of finding the problem.

As data collection tests you could try:

  • Loading an older version of the firmware in case this is a Marlin bug that has be introduced.
  • Short across the ‘S’ and the ‘-’ pins at the board, and run the test. You are looking to see if the message is generated or not.
  • If you are not doing it already, trigger homing from the display.

Wait are you homing all or just the z axis. All will not work.

Just the Z axis. Same effect weather I use the LCD or a gcode command,

I don´t have a Rambo, so not sure if this works, but you could try the M119 command, and check the status of your probe, without running the machine. Check again while manually closing the Z probe contact.

That way you are sure that it “works”.

If it does, try the probing when Z is lifted to the max, just to see if it responds when you touch the bit with your probe.

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Good suggestion.

Thanks for all you help. I’ve got it working. Not sure exactly what the fix was but I reconnected all the wiring and flashed the rambo card. Now everything appears to be functioning properly.



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If the router is grounding the bit to the same ground, then it can sense ground without touching the plate. That’s my guess as to what was happening. Maybe retiring it swapped the g and s around. Or maybe the router was plugged in the first time and not the second.

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