PowerBook G4 1.33ghz wont turn on without PMU reset

[adamrdrew]

Hi all! I've been restoring my PowerBook G4 1.33ghz. It has a problem where if I shut it down it wont boot up again unless I reset the PMU. It also wont wake from sleep. Here are some things I've tried that haven't worked:

• I replaced the PRAM battery
• I removed the main battery as it is completely dead
• I tried resetting PRAM
• I booted into OpenFirmware and did a reset-nvram, set-defaults, reset-all

So far nothing has made the issue go away. Everything else about the system is fine; I don't have any crashes or hangs or anything. I feel like there's some perfect order and combination of resetting everything that should work but I haven't stumbled upon it. Anyone got other ideas? Thanks!!!

 

[greystash]

Try leaving it plugged in (powered) after shutting it down, and try turn it on again. I think the G4s can get into a weird state if the power level is too low and they rely somewhat on a small amount of power draw from the main battery when they're off. I may be wrong but I've encountered this before and I'm sure it was fixed by either replacing the battery or keeping it plugged in.