Z axis crashes into bed

I have Microcenter PowerSpec I3 Plus and recently installed a BL Touch, not sure if it is a 3.0 or 3.1, and have flashed to 4.0.3. (I was on 4.0.6 but rolled back based on some of the threads I found). I am using a glass bed. I have verified the wiring of the BL Touch and it passes all the tests.
Whenever I try and set Z-height from anywhere BUT Leveling, the extruder crashes into the bed and I have to reboot the printer and re-level the z-axis. When I set it in Leveling, using a feeler gauge, and then try and use auto leveling, it fails at the 1st point. I have checked square and level and that all looks good. also my Z-home button doesn’t work. as much as I like ADVi3++, and the fact that is doesn’t randomly switch to Chinese, I am about to flash back to stock… Please help.

It is written on it.

Which ones? It is far better to stay with the latest version.

There is no test for the bed detection and it looks like you have a bad wiring of the white cable.

I double checked and it is a 3.1. also double checked the white wire connection and it was good (good solder and continuity. I flashed back to 4.0.6 and on z height it crashes into the bed still and Z home does not work.

Can you post some pictures of your setup? And what revision is your motherboard?

Sorry, was waiting for a reason to open it back up… Here are the pics. Not sure what board it is, it looks like the standard one. IMG_20200514_173548 IMG_20200514_173602 IMG_20200514_173700 IMG_20200514_175811_MP IMG_20200514_175806_MP

It is written on it: V5.1.

How do you route the cables between the mainboard and the BLTouch?

And do you solder the connectors on the mainboard? They look a little odd. Not sure you have a good contact.

It is a 5.1, found it on the board. Yes the pins are soldered, they have plastic blocks on top. I have checked connectivity using a multi meter and it seems to have a good connection. I am not sure if the board has an issue at that white pin location. Wires are run out through the same slot as the extruder ribbon cable and follows the clips up and over. Here is a pick of the solder joints. IMG_20200516_115642

Do you make the cable yourself? Are do you buy an extension one with Dupont connectors?

I bought the longer wires when I bought the bl touch. They have the black pin connectors on it.

So I think the problem is with the soldering on the mainboard.

Just to be sure: which binary have you used to flash the mainboard?

I am installing octoprint on a raspberry pi later this week. Is there any gcode or command I could send through the printer to test that pin? The soldering connection looks good and has good conductivity. If there was a way to send something through that wire that I could detect with a multimeter then I could troubleshoot it further.

Very often with this pin, the problem is that the connection is intermittent. So it is not possible to “see” the issue with a multimeter (but it is with an oscilloscope). Anyway, let me think about it. I will come back to you after I made some tests to see if I can find a way to help diagnosis the problem.

Is your fan (the back one in your case - the PWM one) running when the BLTouch is moving?

I will check tomorrow when I am wfh. Anything else I should check?

Yes, can you list all the mods you have made? Especially those regarding the heating head, the fans, the board behind the printer, etc.

On the board I added the bl touch. That was my 1st mod. Since then I have added: rear z frame braces, glass bed, opticooler with dual fans, and an led light (uses a bench converter tied into the empty power supply slots, I moved the converter outside the case). I am planning on installing the slanted screen mount today…

So you have changed the stock front fan for another one in the back, right? Which fan? I am asking because this (pwm) fan shared some resources with the BLTouch at the level of the Atmel microcontroller.

I recommend to make a test of the BLTouch without those 2 fans connected too see if it changes something.

I just added the fans, they were not connected initially when I installed the bl touch. Here is a link to the fans.


You have not answered (and just to confirm): which binary have you used to flash the mainboard?