I know there are a million posts about ibooks that wont charge correctly but I think this one is different. I have an ibook G4 (2years old, a part of the battery swap program) that charges normally... for about twenty minutes. Then the light around the charger turns from it's normal "i'm charging" orange to nothing, the light goes out and the ibook switches to battery power. I've just inspected the power chord and there are no strains or tears, the plug at both ends are in good condition and the ibook power socket is fine too. I've turned the ibook off for a period of time (two days) and reset the power manager... still no difference. The ibook looks and acts just like it should until about twenty minutes into the charge then the light turns off and it's like it's been disconnected. The chord is in correctly, i've even tried the apple extension chord = no joy. If i reconnect the power chord at the wall it's fine, starts charging again... and yes i've tried different sockets on different circuits in the house! any suggestions? thanks.