Mori Seiki Tv 30 Z axis problem

Hi there!

I have 2 mori seiki Tv30. One of these two machines always generate some problems. it works the whole day and the next day morning gives some errors. Sometimes the X and Y axis lost the zero point (z70 abs .....)

the last one : Z axis only goes up. The X and Y ok and set the zero. z axis only moves up and and the ATC not Start the zero adjustment.
When i use the pulse generaor wheeel the z axisgoes up and reached the 2nd zero point, but not comming down . The controller said:M01operation error 0003Z when try to moving down.

Before this problem i had Y03amp. uneuipped1 . and s52 servo alarm at z axis but these errors not present now.
I checked the original parameters and check my other tv30 parameters and it looks ok.

please help me to find the problem
thank you
peter