Problem: z-axis movement

Hi,

I have a problem with the movement of the Z-axis. When I print a part the X and Y movements work, but when the first layer is finished the Z- axis doesn’t move and the RepRap is printing over the first layer again.
All movements work in the stepper exerciser, except of the calibration.
When I try to start a calibration the following error is signed:

“Problem during calibration: java.io.IO.Exception: Timeout receiving byte”

I read in the forum that the calibration is not really important, but when I start a print the host software also ask me:”calibrate z-axis”.

Does anybody know what the real problem is or how to solve this?

I’m using 1.generation electronics and the newest firmware.

THANK YOU VERY MUCH!!!

Mathias

maybe some twisted cable on the endstop?

Or somethings wrong with the stepperboard, you may try swapping the x(or y) stepperboard with the one from the z-axis to figure out.

'sid

Thank you very much, the problem was the endstop!

Mathias