Everything else is working now… no z axis home though.
What symptoms/behavior are you seeing, how far do you get before unexpected behavior actually happens?
on klipperscreen, i press move, then home, then home xy and the carriage homes y and then x and then moves to the center of the bed.
press home z and the bltouch does nothing and stays red and the bed motors start to move. I’ve loosed the lower belt connection so the motors dont’ move the bed though. The BL touch is supposed to extend the pin to sense before the bed starts to move.
I just found a burn mark inside the bltouch though (pic a few posts above) and I used the volt meter to verify that when the debug command to extend the pin is issued or the probe is put in touch mode, the voltage output of the sense pin is always zero, so it seems plausible that the sensing circuit is cooked.
Yeah, the commands you shared in our DM last week should move the BLTouch pin down and up…
BLTOUCH_DEBUG COMMAND=pin_down
BLTOUCH_DEBUG COMMAND=pin_up
Bought my legit ANTCLABs BLTouch 3.1 Dec 2020, didn’t start using until this year. Yet today’s model listed for sale on amzn seems to be the same 3.1 with same features, same price. Unsurprised there’s newer cheaper alternatives. Some of the reviews are unkind, who knows how legit they are 
$38 https://www.amazon.com/gp/product/B076PQG1FF
Looks like BIQU released one a few months ago, claiming to be smaller/lighter/more-precise…
$27 https://www.amazon.com/BIQU-MicroProbe-Leveling-Precision-Suitable/dp/B0CC4YKQSK
Would an optical prox sensor work? I know others have used switches and inductive sensors.
The only thing I have ever done is replace the probe pin. There is a small screw reachable from the top.
I am not sure that the probes are serviceable.
It has an electromagnet to deploy/retract the probe, and a hall effect sensor to detect the trigger. A small controller to signal, and manage the deploy/retract electromagnet.
Few serviceable parts that can burn out. The electromagnet is basically a coil of long fine wire. If it overheated, the probe is junk. A hall effect sensor might be replaceable, but is a large portion of the cost of a BLTouch clone, and you need to unwind and rewind the coil to get.to it, I think. The controller is almost certainly easiest to replace the whole probe.
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You guys notice this:
I’m thinking junk. I ordered a new one, but I have an optical sensor that might be a bad idea to use, but it could at least things started.
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Yeah I think I agree with you there. Looks like something shorted inside. I keep a spare on hand just for stuff like this LOL. Luckily its been on hand since I started the V4 build and hasn’t been needed yet. But now that I say that ill need it in a day or 2 LOL
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ok so I grabbed one of the arduino IR object sensors ( like $2.00 one)
Commented out the [bltouch] section and added a [probe] section. Using the bltouch pin header, connected gnd. 5v, and sense pin to digital, I got the z axis to home. Now to mount the ir sensor so it can be used… it will probably not work with a warm bed and vary with how hot the bed is and change if the bed sticker has a white design on it. Likely not the best sensor for this, but it was freely available to try and it worked once the pin was flipped in software. The sensor grounds when the light is detected and it sits at 5v until triggered. wondering if it will require a relay to not trigger during normal operation…
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New bltouch today and it works so the system can now home.
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Anybody know if we can put a lower end stop switch on the bed at the bottom so the drivers don’t try to run down at the very bottom when homing x and y? The bed backs down before the gantry moves… I think that is bad and would like to not do that at the very bottom.
You could do what the Repeat did and model trigger switches at the bottom. The Repeat had optical switxhes on the Z motor mounts. I don’t know if the current firmware supports them, though. There is definitely room on the SKR Pro for them though.
Those.could.lrobably be replaced with mechanical switches easily enough, but I think the optical switches are open high and active low. (Reverse logic to what we normally use.)
I use a Duet for my v4 so my homing sequence starts by enabling sensorless homing and detecting when the Z motors stall, then it brings the bed back up from a known low position to home with the probe.
All that said, when the motors “grind” trying to lower the bed, it doesn’t do any damage to anything, just makes annoying sounds.
It should not do that. The firmware I have should already set it to think it is at Z max at power up and only move when homing Z. If it is doing otherwise you must have some starting gcode with a Zmove it or something.
Not seeing this on mine, for me, Z axis doesn’t move at all if X and/or Y are being homed unless I explicilty set z_hop: within [safe_z_home]. After seeing your post, I just added z_hop: to my Klipper config to hopefully help reduce risk of probe/nozzle hitting plate and/or short something(s).
klipper firmware. There has to be a setting in there.
Nice!
Does your 45deg angled Part cooling Fan (5015?) clear the front 2020 extrusion? Currently modding a franken fan duct after noticing 45deg will hit my lid front…
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yes, it sticks out about an inch or so
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z-tilt runs a while and fails. the bed appears to be tilting up instead of down when it needs to change, so it just gets worse and worse.
Ran into this as well, z-tilt adjustments getting worse with each iteration, I don’t recall fix though. However…
History for my printer.cfg edits mentions …
Which included config change to reverse direction for at least one of the steppers…
Consider checking out that change and others made around the same time. Hope that helps. Cheers!
Edit: Separate from this issue, I found my overall bed level variance was better if I did 4 point tests instead of 3.
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