Original post by: oldnwstf ,
Usually the AC adapter fails on these machines. In fact, I haven’t seen an AC adapter in the last 5-7 years from these series PowerBooks that was still good. But luckily, they are easily repairable, just need a complete replacement of capacitors. I repaired two in last year and they now work as good as new. So, replace or repair your AC adapter (7.5V 2A) and see if anything changes. If you have a voltmeter nearby, check the output voltage on the adapter output jack.