Ok, I'm having a really weird problem with my PowerBook. About a week ago the screen started going black for no apparent reason when it was on battery power. I could still kind of see stuff on the screen, and it was still barely useable, but it was incredibly dark. The equivalent of turning down the contrast all the way, where you can still kind of see stuff on screen, but it's really impossible to get any real work done that way. I have no idea what is causing this, it just happens when I'm on battery power, not when any particular program is running or anything. It happens completely randomly, too, sometimes it'll be five minutes, sometimes half an hour between occurrences. If I put it to sleep and wake it up the screen is back to normal. Again, I have no clue what is causing this, and haven't found anyone with a similar problem yet. Any suggestions? Oh, the PowerBook is a 667Mhz PowerBook Ti.