hello,
i have a sony vgn-cs series laptop the charging board i repaired now has the stdby voltage 3.3 and 5v but when i push power button comes on for a sec and goes off.there is no shorting on the board everything seems fine.i supect the sb 82801hbm what else can i check before changing the sb.

there are other voltages (for RAM, video etc) exept stby, how about them ?

Check NB and CPU-power circuit