sony vaio power problem help urgent

[razu]

Hy friend I have a sony vai laptop its second power mosfet cant pass the draind voltage but its gate have 19.5v . when I short the mosfet the laptop is start and first mosfet is over heat, mosfet number is AO4433..


diagram page number 43 and pq25 mosfet

laptop model is VGN-NS110E
motherboard part no: mbx 202


please help me Urgent

[multiplexer]

Re: sony vaio power problem help urgent

Likely short on pins 5-6-7-87 of PQ25 or PU1 failure.
Measure the resistance to ground on pins 5-6-7-87 of PQ25.

[razu]

Re: sony vaio power problem help urgent

There was no short but the voltage cant go the pwm Ic

[shijeesh]

Re: sony vaio power problem help urgent

Please check PU1 pin 28 PVCC how much voltage, pin 5 ACDET voltage and pin 13 OVPSET voltage.

[fddizon]

Re: sony vaio power problem help urgent

the unit is in protected mode.
short or leaked capacitor or upper fet along b+ rail are the most common culprit of this issue.


try isolating supply on each section by clearing solder on jumper and trying to power up each time.
if mobo starts then you know where to start finding the faulty part

[razu]

Re: sony vaio power problem help urgent

Hy shijeesh

the PU1 voltage is

pin 28 = 19.5V
Pin 05 = 0.64
Pin 13 = 0 V

[razu]

Re: sony vaio power problem help urgent

Hy fddizon

How can I isolating supply on each section please give me video or image and How can I find leakage fet or Capacitor Practically