Frequent Ibook G4 Freezes When Unplugged

[ceads]

Hi There,

I have a 1 GHz 12-inch ibook purchased in July of 2004. A few months ago I began having frequent freezes when not plugged into the power adapter. These freezes usually happen within a few minutes of startup and cannot be helped buy a force quit or soft reset, only a manual shutdown with the power button. The battery is calibrated and fully charged. I checked and found that nor the battery or the logic board is covered under apple's replacement plans. I haven't tried a PMU reset yet, would that be a first step or is it for sure an issue with the logic board?

Thanks,
Clay