Mark
Mark
there is a version text on the sensor on the other side of the white connector, like v1.3 or v1.1
does the led on the sensor work? it will light on if it detects the metal else off.
then from the hardware, we can only to find if the problem is from the dead mcu or the cable. do you have one more cable to replace the old...
if you have a solder tool you can try to connect to a serial model, there will be many useful data output from the serial com port.
> Do I need to open the case for that? No 
> Would a ST LINK work? No, the MCU on the v1.1 is not stm32
did you calibrate the bdsensor? and what's the data returned after M102 S-5 ?
you can try to decrease the `homing_retract_speed `in stepper_z, for example `homing_retract_speed:2` or disable the second homing by set the `homing_retract_dist:0` in the stepper_z and also attach klipply.log
what's the returned value after M102 S-2 instead of M119, it seems the returned value is -0.12
I also suspect the electronic noise from other wires for example the motor or heater. could you try to test the homing by sending a lot of G28 Z to...