Recently my powerbook started to shut down every time i unplug it. And then, when i switch it back on the date is always on the 1st of january 1970. I dont know what to do???
There is a small battery on the motherboard, I remember when one of our computers lost sense of time it was usually that battery which needed replacing, maybe this is connected with your shutdowns, don't know in what way though, sorry
But you might want to try resetting the PMU and zapping the PRAM
well the date and time resetting can be an indication of a dead logic board battery (not the battery that runs the machine). you could also have a dead battery(the one that DOES run the machine) or perhaps it isn't seated properly. make a quick visit to the Apple Store and they'll test your battery, power supply, and machine in a few minutes. most likely you'll walk out with a free replacement part and 10 minutes missing from your life. not too big a deal.
I think Darwin is on to something. There is probably an emergency battery in the powerbook that is supposed to keep things going (and remember the time) when external power and main battery fails. It may very well be that this emergency battery is needed for a brief moment when the PB switches from external power to internal battery.
this is exactly the case - powerbooks' battery behaves just like UPS, meaning that when the battery is full, it is left alone and the power doesn't go through the battery.
(usually the power goes always through the battery to make things simpler and easier to build. but that slowly destroys batteries.)
Until you figure out why your battery's acting up, you'll have no other choice but to leave it plugged in. Do you have an Apple Store or place that diagnoses/fixes Apple computers near you? If you do, I'd take the PowerBook there, explain the problem you're having, and see if the folks there can get it fixed.