NP700z5b-w01ub won't power up on AC.

Hello,

My laptop work fine on battery, but won't power up on AC. With AC adapter plug-in, the blue (power indicator) led light does not light up. I took the back cover off and verified that 19.2 volts is present at the pins where the power jack is soldered on to the mother board. Any suggestion what to do next is much appreciated.

Thanks!