Well sell me your back light unit (just kidding as i know you just got it). I don't see any of the older powerbooks or anything else having that screen size. Did you recap your inverter board yet? That has been mentioned as a weak link before. Maybe why it worked and now doesnt. Did you try going back to OS 6.0.8 or whatever it came with? I know the system 7.1 and 7.5 disks list power issues and sleep issues with the portable because of hardware uniqueness like the hard drive and battery pre laptop (although that may be the non backlit model of course).