How long have you had the laptop for?
symptoms:
Won't charge the battery, won't power from AC.
Also if you power the AC adapter when not connected to laptop you get green power LED on the adapter. When you plug it in the laptop the green power LED immediately goes out.
Opened it up and found SO-8 P-ch mosfet by the DC input socket. Source (pins1,2,3) is connected to the inner barrel (+19.5V), Gate 4 gets driven low, applying the input to the Drain. (pins 5,6,7,8) On my board the drain was short to GND. Applying power directly to the Drain via a current limited bench PSU (set 1A limit) showed a couple of volts.
Placing a finger on the opposite side of the board revealed a SMT ceramic cap getting hot.
CP13 I think. Opposite side to the power connector, almost under it. I would guess at 1206 or slightly larger and there is an 0402 cap just next to its bottom pad at 90 degrees to it. Cap was glued before soldering so had to flow both sides at the same time with a soldering iron and force off. Would likely have been 1uF or bigger 25V. Removal restored operation. Runs OK without but would suggest putting something in there 0.1uF 1206 50V, perhaps a couple stacked ?
BTW you have to strip down everything and remove the main board to get to the cap :-(
Hope this info is of use to someone....
(EDIT) correction: cap is PC13. Pic showing location of failed cap - D505fix
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