B&w 400mhz G3 Tiger Won't Wake Up


I have two hard disks in a B&W 400MHz G3 machine with a OrangeMicro 906F SCSI card, 384 meg ram, no peripheral attached. One of the drive is partitioned, primary partition has a clean installed Tiger, the other has OS9.2.2 installed. Once Tiger goes to sleep mode (either by time out or start button), it won't wake up, pushing command-control-start button is the only way out, but that procedure corrupts one or more volumes of the same hard disk, DiskUtility always report a "leaf node" error that cannot be repaired. I have Panther installed in a volume in the other hard disk, it isn't affected, sleep under Panther always function normally. I have erased the volumes, reinstall Tiger, immediately, the same problem came back, updating to 10.4.2 doesn't improve anything. Booting back to Panther, things are normal again, so the problem must lie with Tiger compatibility with my G3. I have also tried loading up a CD when it's asleep, the DVD drive spins up and appears to load it, but pushing the eject button will eject the CD, showing that the CPU is still sleeping. Switching off the monitor and switching it back one doesn't help either, it's still all black. Please help.