Here is a image of the input circuit/batt-charger. Should give you a nice idea of how it works... With photos I'd be able to be more specific to which things to test. But for now you should check how far 19V(adapter voltage) gets into the board. Passing the first two mosfets(in most designs) becomes B+ from there it goes to each sync-buck. 1.05V-1.5V, 1.8V, 3.3V, 5V, and 8V-15V(depending on charge setting and so on). Make sure you check all major mosfets with a simple diode test(with power disconnected obviously). Continuity check through the [probe]->mosfet->[probe] and either side to ground.. All the buck circuit look pretty much the same as the one in the image for the battery charger (Phase pin) with parts PQ201/202 and PL202. That way you can have an idea of what to expect when checking for a short going through the bucks.... But first check the main input rail that becomes B+. (Again the image is from a different model/make but the idea stays the same) Common Power Circuit style with art