New LR3 Build end stops, probe and homing issues

[Bartman]

@Bartman

I’ll post some links and some more information

There are two ways to add a resistor to the circuit.

One way is to solder a resistor directly between the the leads on the underside of the board. If you are confident in your soldering skills, this is an ok way to go, but as noted in one of the linked posts below, it will void your warranty.

The other way is to fabricate a pigtail. If you don’t feel comfortable with your soldering skills, then the pigtail is a good choice. Plus it won’t void your warranty.

There is a third option of breaking the LED, but you lose the visual indication and it definitely voids your warranty.

Here is a post that links to some background information

Troubleshoot

There’s a chance you have an SKR pro with a known issue. Here’s the thread where it was first identified: Here’s a thread showing how this can be fixed by soldering on resistors: Here’s a thread showing how this can be fixed by making a wiring pigtail adapter with integrated resistor:

In either case you want to connect a resistor between the two outside terminals (5V VCC and SIG)

Here is a post of mine where I summarize the options

SKR Pro1.2 X-Endstop issue

Welcome to the forum! We have your back! If the endstop is showing triggered when it isn’t activated, you have an open circuit. Check your connections, especially if you are using an extension cable. Also test the switch itself to ensure you are connected to COM and NC, and that the switch is 0 Ohms between COM and NC when not asserted. If you are using the crimp connectors, check that you crimped on the metal, not the insulation (use an Ohmmeter). Solder connections are permanent, but more…

It links to another thread that has a hand drawn schematic of how to electrically make the pigtail

Right Z won't home correctly

Note that one of those linked threads shows an incorrectly built pigtail. You want it to look like this electrically (picture copied from later in that thread) [image]

Here’s another post of mine in the same thread that has a bit more info.

Right Z won't home correctly

From the V1 SKR Docs page, [image] You want to use the resistor to jumper the red X (5V VCC) to the green dot (Signal). The switch leads from the switch still go from Signal to Ground (yellow G). Never allow Ground and 5V VCC to connect to each other (which would happen if you reversed the 3 pin female connector so that the resistor and Signal wire were touching VCC instead of Signal). Hope that is clear enough, Here is a post that shows how to make the pigtail (although he used a 3 pi…

From a different post in the same thread:

“MAKE SURE that the 3 pin connector is attached so that only the resistor (and not the resistor and wire) is touching the VCC pin on the board, or you can permanently damage it”

Here is a post that shows how to physically make the pigtail.

Problem with x not stopping when homing

Below are photos of how to make a pigtail to solve the pullup problem without soldering to your board or do anything overly complex. Items required: 1.5k resistors HiTec Servo Terminal Kit Crimp Tool Heat Shrink Tube Process in photos: [pigtail1] I make the smallest little white wire possible so it can go into the connector and also be flexible so it can fold over in your case. I then solder the resistor wire (shortened of course) to the white wire. [pigtail2] [pigtail3] [pigtail4…

@Geoff_Crocker

having wired the first pigtail incorrectly (potentially damaging the board)

There’s a way that you can check if the board is working or not. Firstly check that all 3 VCC LEDS (orange) are on. Then jumper the two pins on the 2 pigtail 2 pin connector (the side that connects to your end stop switches), or simply connect the endstop wiring to the pigtail and assert the switches.. If the LED asserts and the M119 shows Triggered on every end stop circuit, then it should be okay.

Hope this helps