Smart-pin power connector HP 6715s

[desigabri]

hi, I brought an HP 6715s notebook from eBay and it never booted. So I searched for hardware problems onto Mother Board and found that the previous owner broke the power switch by means of a screwdriver or something similar. I asked informations, pictures, schemes about it in this forum some months ago without success, I searched them throught internet and so on always without success, and the last time I guessed that notebook power connector is a bit strange for me: the power source isn't like standard types. The notebook is an HP 6715s. The Power connector has the ground on the external ring side and +19V into the internal ring side. There is another central pin that is something more then 12V voltage but after connected it goes to about 5,9v voltage. HP information explain that the power source is "smart-pin" type and informations over the web say: 1) that the central pin should be usefull for saving power tecnology; 2) others write that it is needed for to say to HP notebooks that the Power source is an HP original; 3) others that it is normally grounded and that it's used to tell to the notebook that power supply is connected althought that the batteries. Someone says that they can use any power source for those HP notebooks, someone says that notebook doesn't turn on if they haven't a smart-pin power source type. I'm a bit confused because I can't find any absolutely right information. I can't find anything about pinout information, I don't know what is the right voltage for the central pin; I really don't know if it is needed for to say something to the notebook, or if it listens any kind of signal from the notebook for control purposes or anything else. I would like to receive any kind of informations about this problem please. Any help will be apreciated thanks in advance

[Spippolator]

After some years....
THE solution: put a 390k (orange-white-yellow) 1/4 or 1/8W resistor between center smart pin and 18.5V. Remember that the power ground is the external shield and + is the internal shield.
I found this from a broken hp power supply.

Spippolator form Italy