I have a 12" Powerbook G4 1.5" and lately the screen randomly turns itself off, the whole thing goes black, like it was asleep or off, but the computer keeps running just fine. The computer itself stays running. What I've been doing is putting the computer to sleep by closing the lid, letting it rest for a few seconds and turning it back on by opening it.
I can still see that the screen is on, but the display is dark. It randomly does it. I switched the power settings to "never" for sleep and like 5 minutes for display sleep. That worked as long as its plugged into the AC adapter. When I unplugged it it did the same thing. I closed the lid and then it went to sleep and then I opened it and switched the battery settings to the above, and it was fine.
I set the PMU and NVRAM again. So far it's not doing it but I am worried that it's a backlight issue or something else? I have heard of random sleeping problems with the powerbooks, but mine doesn't actually go to sleep. Any insight would be great. Thanks!