<p>I found the problem. I'm using an aluminum structure for my gantry. My Chinese power supply was in contact with this structure. There was a current leak from my power supply that was messing with the Z-probe signal.<br />
I detached the power supply, everything's gotten back to normal, except it had my board and TMC2100 drivers fried a week ago.</p>

CC BY-SA 4.0
2021-02-18T16:02:41.090Z
2021-02-18T17:57:13.760Z
2021-02-18T17:57:13.760Z
2012User
<p>I'm using Marlin. Recently my Z-probing randomly doesn't work. Sometimes during Z-Homing <strong>it goes up</strong> instead of going down to sense the Bed! In  Bed Leveling it goes higher and higher every time. It got frustrating so I ignored Bed-leveling.</p>
<p>Sometimes I get a fine Z-homing but it always <strong>starts printing in the air!!!</strong> I have no Idea why it happens. All home and axis offsets and setting are fine. I had no problem last time I used my printer.
Why my printer starts printing <strong>5 mm</strong> in the air?</p>

CC BY-SA 4.0
2021-02-10T20:56:23.957Z
Out of the blue? Or, did you change something recently?
0scar
CC BY-SA 4.0
2021-02-10T21:01:18.700Z
My MKS Gen_L V1 and tmc2100 drivers on X,Y axis fried for unknown reason! I replaced them with the same board and LV8729 drivers. then I changed the settings for the new drivers.
2012User
CC BY-SA 4.0
2021-02-11T14:43:12.080Z
I had problems with z-probing before that! I guess this maybe related to what happened to my board.
2012User
<bed-leveling><z-probe><homing>
Marlin Z-probe Failure!
2012User
# Marlin Z-probe Failure!

(Asked by: username_0 on 2021-02-10)

I'm using Marlin. Recently my Z-probing randomly doesn't work. Sometimes during Z-Homing **it goes up** instead of going down to sense the Bed! In Bed Leveling it goes higher and higher every time. It got frustrating so I ignored Bed-leveling.

Sometimes I get a fine Z-homing but it always **starts printing in the air!!!** I have no Idea why it happens. All home and axis offsets and setting are fine. I had no problem last time I used my printer.
Why my printer starts printing **5 mm** in the air?

**Tags:** bed-leveling, z-probe, homing
> **Comments:**
> **username_1**: Out of the blue? Or, did you change something recently?  
> **username_0**: My MKS Gen_L V1 and tmc2100 drivers on X,Y axis fried for unknown reason! I replaced them with the same board and LV8729 drivers. then I changed the settings for the new drivers.  
> **username_0**: I had problems with z-probing before that! I guess this maybe related to what happened to my board.  

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## 1 answers

### Answer by username_0 on 2021-02-18. Score: 1 | Accepted answer

I found the problem. I'm using an aluminum structure for my gantry. My Chinese power supply was in contact with this structure. There was a current leak from my power supply that was messing with the Z-probe signal.  
I detached the power supply, everything's gotten back to normal, except it had my board and TMC2100 drivers fried a week ago.


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