It’s been reported that some EZABL kits (V1/V2/V3/V3.1) are not registering triggering on some EZBoards (V1.0-V1.2). This is due to the Opto IC not pulling down the voltage enough to register that it is triggered. This was not ever found to happen during testing so we have this workaround to fix the issue. We suspect that the reason for this is that the yield on some optos is different enough to cause this to happen on some boards and isn’t something that is easily able to be tested. Meaning the pulldown is less on some optos that is still within the manufacturer specification but just different enough for the CPU to not register the trigger.
To fix this we can connect the z endstop to the SERVO header on the GND and SIG pins and use the #define V3_EZABL_ON_SERVO option in the latest firmware (U2.R1.8 or higher). Use 2 male to female connectors to connect the 2 pin Z endstop cable to the header. See pictures below for how to connect.
If you do not get TRIGGERED/Open on the first try swap the 2 wires on the GND and SIG pins OR if you have the EZABL Pro just flip the switch on the board to the other position.