Plugged BLTouch Z-Probe the wrong way. Probing not working.



  • Hey everyone, so I just had an absent minded mistake. I was re-routing some of my wiring and had accidentally plugged the BLTouch's z-probe leads in backwards swapping the IN with GND and vise versa. Now the z-probe trigger no longer works. The pin does not retract when it is supposed to trigger.

    My big question is, was this a 35 dollar mistake, or a more expensive 170 dollar mistake. as in which component is now faulty. Each seem to work fine aside from the z probe signal not triggering. I run the BLTouch self test, it runs just fine. pin-up and pin-down macros operate as they should. My duet2 wifi doesn't seem to be screaming any error codes at me.

    I want to say,I might have fried my Touch as they seem to be a fickle piece of hardware. When I depress the pin to send the trigger signal after about a second the bl goes into alarm state.

    I had been looking around for a while and can't seem to find any resource that could answer my question, so I am posting here to see if anyone has any experience with this scenario.



  • I haven't done exactly that, but you can test each pin of the Duet much more easily than the BLt

    Duet 2 or 3, and what port(s) was the BLt plugged into?



  • Duet 2 Wifi, the z-probe harness got accidentally switched at the plugs close to the sensor. So the "IN" lead from the board got plugged into the "GND" of the BLTouch, and the "GND lead from the board got plugged into the "IN" of the BLTouch.

    I'm not familiar enough how the z-probe on the board works so I don't want to start poking around and causing more harm until I know how to diagnose it properly.

    as far as the other 3 leads.
    I have +5V lead (red) going to pin 1 on the expansion header
    I have GND lead (brown) going to pin 2 of the expansion header
    I have Signal (yellow/orange) going to pin 8 (heater3) on the expansion header



  • While I can't speak for your particular case, I have found the BLTouch to be relatively forgiving of my screw ups. I would check the fuses just in case ....
    I would also check out the wiring in general (or anything else you touched as this was happening)

    Good luck !



  • So I decided to pull out my DSO and give the Z-Probe in signal a looksie to see if the BLTouch is sending a signal. And indeed, it is sending a signal and for some reason that still has me scratching my head, now it works.... dunno why but it now works. Didn't re-seat any plugs just probed some leads.

    Anyways hopefully it stays that way. Thanks everyone who replied.

    Cheers!



  • @kanakaRed said in Plugged BLTouch Z-Probe the wrong way. Probing not working.:

    So I decided to pull out my DSO and give the Z-Probe in signal a looksie to see if the BLTouch is sending a signal. And indeed, it is sending a signal and for some reason that still has me scratching my head, now it works.... dunno why but it now works. Didn't re-seat any plugs just probed some leads.

    Anyways hopefully it stays that way. Thanks everyone who replied.

    Cheers!

    DSO magic. I've seen it / done it many times. Also, my wife is apparently magical, because if I explain a failure to her, it won't do it while she's in the room.



  • If the magic smoke doesn't escape and you don't smell the smell of death, there is a good chance it's just fine .... looks like you lucked out!
    You might have a bad crimp joint though ... but don't touch it until it acts up again 🙂



  • Should be fine. if its an older style bltouch, it may not be working because of the voltage its set to. i had to cut the small metal contact point on mine to work with the duet board, although Ive seen some places that they removed that strip and it should be auto-sensing.


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