Power problem HP ELITEBOOK 6930p

[claudyu07]

hi guys. i have this hp elitebook 6930p here with power problems. when charger is pluged in , the battery light will blink very fast and not turning on.Also light from charger does the same and indicates a short if i am not wrong.
Motherboard is : KARIA DISCRETE 07219-5
I have uploaded schematic here:
http://www.upl.me/b0XDO1

when checking mobo i found U2 wich is AO4407A p-channel mosfet very hot.
i have replaced it with FDS4435 . Now battery led lights normal but after 1 minute mosfet get's hot and starts blinking again.
Replaced it again and remove U3 which is same mosfet AO4407A,(mosfet u2 is not hot anymore) and try to check u2 with DMM for voltage:
Pin 1,2,3 SOURCE 19v
Pin 4 GATE 16v
PIN 5,6,7,8 DRAIN 19v

When replacement for u3 is on board , even if lights from battery lights normal i have no voltage on pin 5,6,7,8 of mosfet U2 and U3
Any ideas where i should check ? thanks

[claudyu07]

Re: Power problem HP ELITEBOOK 6930p

Bump

[tibd]

Re: Power problem HP ELITEBOOK 6930p

Check Q2 for short, surounding elements?
Checked LIMIT_Signal at LM393 i think its U5 in you schematic?

[dj_ricoh]

Re: Power problem HP ELITEBOOK 6930p

find L5 and take it down and see if it gets hot

[claudyu07]

Re: Power problem HP ELITEBOOK 6930p

thanks guys . short on mosfet q2