vaio vgn-s28gp

会员135031

hello all.
i have three dead sony notebooks all vgn-s series changed the south bridge now 2 power up but no display also check the bios the debug card show only 00 and clk.the other when i press reset button 3-4 times then works well but sometimes no 3.3v and 5v.the max1908e pin1 is dcin which is absent .the main switch 16v adapter is a mosfet dual p-ch si7954 which is in series with a diode and resistor when drops to 4v accross diode then supply starts .anyone know on this sony models i have put new SB bga chips any diffrence is fw82801dbm and NH82801dbm.
thanks