Ok,
Thanks you for all your reply
i will test to unscrew method

but ok if happen is not a problem i didn't know that

hmm is there a way to mark this thread solved ?

config.g
bed.g

ok thanks
this explain why i have the error but this doesn't explain why the bl touch blinks two times somtimes
when i'ts the case a can see a very fast "1000" state in red on web page on dashboard/the sensors/status/zprobe
but it disappears too quickly to take a screen

does i need to use mesh compensation ?

I have Installed a Bl Touch on my alfawaise u30 based 3d printer and i can't use the bl touch.

I have sometimes message like this :
Skipping grid point X=205.0, Y=45.0 because Z probe cannot reach it
and the bl touch blink two times

to fix that i have try to shild the bl touch wires with aluminium, solder a big capacitor near to the bl touch on the power calbles.
In my tests that i made i have failed and kill my first bl touch with 12v so i buy a new one and i have exactly the same problem.
So the problem can't be the bl touch.

i am thinking that my wires are maybe to long ( i use the extention cable of bl touch )

as you can see on the pictures, I connected an oscilloscope on the wires, and the signals look ? ok
I don't know what these signs are, so I have a hard time to know what else to do

the yellow it the yellow xire the blue is the whight wire, i have record a z probing config.g homez.g IMG_20220425_114558.jpg

my configs are made by the website config tool with addition of a line to setup the end of filament detection

https://cdn.discordapp.com/attachments/891812298514137088/968097828176019467/VID_20220425_114532_comp.mp4