Something weird is going on with these Powerbooks and chargers.
My charger works fine most of the time, but occasionally stops charging without me having touched, unplugged or changed anything. My laptop is plugged into the charger 99.9 % of the time, I basically just use the laptop as a desktop. It will run for months on end without any problems and then, one day, unexpectedly, I may notice that the lighted ring on the charger's plug is not on, or, if I missed that, I get a warning that my computer is running on spare battery power, even tough it is still plugged in to mains power. This will then happen every day, usually only once a day, sometimes twice, for a few weeks or a month or so, and then the issue goes away again for a few weeks or months.
The remedy I have found is to unplug the power cord from the charger, leave it for a few minutes, then plug it in again and everything will be fine till the next day. Unplugging the lead form the computer itself does not work, it has to be the mains lead that plugs into the adapter. If I don't wait long enough before plugging it in again, the problem repeats itself straight away, i.e. the charger stops charging after a few minutes.
It does not happen at exactly the same time every time, no apparent connection to hot or cold days, it is not a charger over-heating problem, it's not re-produceable at will - it's just completely baffling! I have two chargers, both do the same thing. I have re-set PRAM, no difference. Tried all sorts of things, no difference.
It is a known problem; I have searched the net for a solution and found others have had the same issue. I have found "remedies" suggested by others, but nothing seems to fix this issue.
Anyway, it's no biggie, just a annoyance, and a mystery I haven't been able to solve. Apple must have put it in the "too hard basket" themselves too, it has been discussed on Apple's web site forum, but no solution there either.
I guess this Powerbook will eventually take this mystery to its grave ...