I hope these experiences will be useful to someone else. If your monitor shuts itself off after a random amount of time, one of the likely sources of trouble is a defective high-voltage monitor. This was covered until March 31 by an unannounced warranty, but no longer. 53-54 for a quick fix anyone can do in 10 minutes that may save you an expensive trip to the shop. I have repaired dozens of these.
Monitor appears to shut off.
Green power light goes out. Described by Pina. Never seen it help. Has always fixed this problem. Expensive part and hard to find.