Hi, I have a powerbook G4, aluminum case, and recently it no longer would get juice thru to run the thing or charge the battery. Definitely not an adapter problem. Someone told me that there is a small internal battery, I forget what it's called, not the CMOS battery but the other one, that if it goes bad, will produce these symptoms I'm having. Well, I actually got the case open, but I can't find any batteries in there. I have not attempted to pull out the circuit board or anything to see where the batteries are hiding.