Z Motor Problem

Hi,
Recently finished the build, running Repetier Host v1.0.5

Was having problems with the Z motor, found a faulty variable resistor on the comms board and have since switched that out
Z arm turns fine now, voltage at 0.55v

However, in Repetier sending the home command for the Z makes it move up ~5mm, not down towards the microswitch
Microswitch also doesn’t stop the z arm, wiring seem correct.
Up and down controls in repetier seem to be working fine, but previously only up command would work (not sure why thats changed)

Any thoughts on what could be the problem?
Thanks

With what version of Arduino did you upload the firmware?

If the Z axis goes up this indicates an open on the end stop for the Z axis.
VEL337 is correct you should not use Arduino software above 1.0.6
You can download it from here.
https://www.arduino.cc/en/Main/OldSoftwareReleases#previous

Since you are just starting you should use the version of Repetier from this download.
http://www.k8200.eu/downloads/files/downloads/setup_repetierhost_k8200_0_95f.zip
This has the ini files for the K8200.