Solved Debugging an homing error with conventional endstops

[BigBadWolf]

Printer Model

Voron 2.4

Extruder Type

Clockwork 2

Cooling Type

Stealthburner

Hey guys,

thats my first question here, got this step from lurking to asking because my 2.4 baby (1 and 1/2 years old, usually working daily like a charm) got a problem I am not able to fix by myself:

1. When I home the printer, the x-axis homes perfectly including the "second hit" after retract.

2. The y axis moves a bit and stops, as if it hits the trigger midair - even when it is around the center of the printer - followed by the retract motion. In fifty percent of the cases, Klipper tells me "Endstop y still triggered after retract" and in the other 50%, the "invisible wall" will be hit a second time.

3. When the x/y homing works (with the invisible wall!), the printer is ready to home z, which usually crashes into the bed, because it is not even close to the z-endstop.

And now the clue: When testet manual with M119, the y-endstop works fine. Open/Triggered status is 100% correct when I push the endstop by hand.


I already replaced the endstop-button, just to be sure, but this changed nothing. The wires don't seem to have an issue, they measure fine.

Where could I go on with debugging? I am happy about every glimpse of an idea.

The board is a BTT Octo 1.1, the printer runs Klipper on a Raspberry Pi 4 and Octoprint - just in case any of this informations is helpful.

 

[Sandman50]

My guess would be there is a wiring error that give false detections. The problem with intermittent wire issues is that they are hard to find. Perhaps run a new set of wires (they don't need to be in the drag chain for a test).

 

[BigBadWolf]

You think it's possible, that there is a "broken" wire somewhere, that only loses contact while in motion? Since i only measured the cables without the gantry moving, this is completely possible. I will try a new set of wires and test the endstop again.

 

[Sandman50]

I've also had bad crimps and bad insertions on the connectors to the main board.

 

[BigBadWolf]

Thanks alot, it was in fact a bad crimp on a connector, that only disconnected now and then while moving. Easy to fix, now it works like a charm. Thanks for the input!

 

[mobile_pilot]

I'm having a similar problem, I just found out to be the connector (mine is Fysetc connecting to a XY D2F limit switch board). Part of the problem arises from the tight space between the back of the printer where the Y limit switch triggers, and the board cable output. The portion of the 3/4-wire cables coming out of the connector are bent nearly 90 degrees. They get squeezed against the back of the printer during the Y homing, precisely when the Y endstop is about to trigger. One of my 4-cable harness was severed after 340h of print. Luckily I only need 3 to run D2F switches, but it's not reliable as when I apply pressure over the connector with my finger it results in x , y or both switches triggering. Bummer, I might get rid of this board and make a better version of it.