SNK w/ 31i Model A Fanuc Motherboard Alarm

We arrived to our shift with a hand off for an SNK HM5 with a 31i Model A Fanuc system having had some kind of motherboard alarm. Previous shift did not save the specific alarm, specified they arrived to a black screen with the alarm. They cycled the main, alarm went away. But now Z Axis in motor feedback goes into overtravel before ever reaching the limit switch when attempting to reference, and excess errors when you go in the negative direction.

I learned earlier today this same machine experienced an issue where it wouldn't power up, so they swapped the power supply. Only the supply had been installed brand new just last week.

Any advice on this issue is greatly appreciated.