Z axis keeps going down and hits print bed without stopping

I have purchased a second user CR10s pro it was sold as a V2 but in fact is is a V1 with a failed CR touch upgrade. I have no problem as the seller was very clear and the price was good.

I checked his wiring for the touch it looked ok. The problem it was having (before and after I put the v1.70 firmware on the screen and controller) was that when homing the print head moved up and the BL touch probed twice and it stopped 29 mm higher than were the head was.

Reading this forum and elsewhere I moved the black and white wire from the Z-- to the Z+ connector and now the print head moved down and the touch probe extends as I would expect.

It just does not stop when it hits the bed. The power on test of the probe seems correct.

Hi Brittain

Welcome to the forum, Glad you found us.

First things first I am sorry this is going to be a long-winded answer. Do you know if the CR touch is functioning? I know you had said that the probe deploys 2 times, does this happen on power up?

just a note you are troubleshooting this issue that the firmware denotes where the CR touch wires should go. You need to have firmware that is documented where the CR touch wiring goes. Sometimes it’s as simple as reversing the Black and White wire.

It will basically work like this, I will explain from BLtouch as it’s what I am most familiar with but I believe the CR touch is the same. If someone here knows differently please jump in.

There are 5 wires on a BLtouch, Brown, Yellow, Red, White and Black. Their purposes in the same order are Ground, Signal, V+, triggered output, Ground

Think about it as being 2 circuits in one device, the Brown, Yellow and Red are only responsible for deploying the pin and retracting the pin. that is their only function. The red and blue lights provide feedback as to what the BLtouch is doing but only to the effect of if the pin is in or out.

The triggered output and ground only trigger when the pin is being pushed by the bed and passes the hall effect sensor over a specific trigger point halfway up the BLtouch, (note this trigger point is located halfway in between deployed and stowed).

So that being said from your description it appears as though the digital side of the switch is working (yellow wire) but the trigger portion is not.

I would suspect that the firmware you have is meant to have the black and white wire plugged into a specific port or order and it’s just not seeing the “trigger” part of the BL.

Hope this helps. and hope to see you often

I don’t own a CRtouch eaither. I seem to remember others with similar issues too. If after attempting Jasons advise if it fails it might be worth trying a BL. I can’t find the post I am thinking of but that person ended up with a BL touch instead and maybe a board too, I am sorry I am sketchy on details it might be from multiple posts.

Yes this does help. I need to decide on on firmware I guess the tinymachines makes sense. I will probaly test the trigger is working and if it is I probably have it in the wrong place. I will post when I have made progress. Thanks

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I have just taken the cover off and it is actually a BL touch, I started thinking it was a CR10s pro v2 as it was sold as a v2. It was a BL touch v2.

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This is now solved. I ditched the BL Touch version 2 and purchased the cheapest 3d touch clone for £12 and put Tiny machines firmware on the controler and screen. TThe clone came with a new set of cables so I redid that. Thanks for the responses.


awsome, glad you got it running, Thanks for letting us know.