The internal pin of the power connector (inside the laptop) broke. (page 20 in manual, element 1)
I put the now movable pin into the jack of the adaptor and for about two years used it in this way! Then, the jack (looking more or less like this http://i297.photobucket.com/albums/mm216/looneypc/DSC00...) which was heating lost connection, so I had to remove the plastic cover of the adaptor’s jack end, reconnected the wires, put that pin inside the metal tubular end of the jack and used it like this for some time. Now I lost connection again, something wrong with what remains of the connections inside the jack I guess.
The power connector is directly linked to the motherboard I think.
I would like to find a way of connecting my computer to power through other means, like using the battery slot or even better the slot of the travel battery connector (page 24-25 in the manual, element 8). These female connectors are different in form. I think that I need a male connector that would fit one of these and put it at the end of my external power adaptor.