Temo, When you go to start the machine ( try to take it out of an estop condition) can you hear anything? Such as any motors/ pumps trying to turn or any relays/contactors trying to pull in. Is that when the fault appears? Having prints can help a lot. Many years ago Cincinnati machines did have blue books that helped find machine problems. Can you tell us what model machine you have and what kinda of control it has on it?
Not sure what kind of experience you have, No matter what kind it is it will pay to be very careful. FanFan