I have a 1998 OKK MCV 660 with a Meldas 600 controller. I keep getting an alarm for sy0020 SV initial communication error for the z axis. If i cycle the machine enough times, it will start working again. Never fails until i power off the machine. I thought the drive was going bad so i replaced it and still has the same issue. Also after i replaced the drive, the home position is lost. How do I teach the new home position?