Marlin Z-probe Failure! 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?
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.