5742 (LA-5893) No turn on

R EZ A

Hi guys
This laptop turning on with battery,but no action with ac
It use 0.04 on ac
and it hav 8-10V on B+
Pq21&pq52 gate are high

What is the problem?
Tnx all

andromedax

R EZ A писал(а):

Pq21&pq52 gate are high

Measure the voltages of PQ63. (pin1, pin2)

PQ63 shoud be saturated, (high level on pin2) in order to establish the correct voltage on gates of PQ51 and PQ52.

Check level voltage from ACOFF signal.

R EZ A

ACOFF=0V

PQ63 gate=0v
PQ63 Drain=19V

andromedax

R EZ A писал(а):

ACOFF=0V

PQ63 gate=0v
PQ63 Drain=19V

Measure and post all pins voltages of PD15.

Also check voltage of VL rail.

gs84

R EZ A писал(а):

Pq21&pq52 gate are high

what you mean? Say in values volts. PQ51 and PQ52 already checked?

andromedax

gs84 писал(а):

what you mean? Say in values volts. PQ51 and PQ52 already checked?

Why do you suspect PQ51 and PQ52 are damaged?
Main problem is PQ63 not being correct polarized. PQ63 Drain=19V is not a good voltage for Pq52 conduction.

R EZ A

VL=5V
ACON=0V
MAINPWON=Variable 2.5-4V
PD15 Pin1=Variable 2-3.5

PACIN=0V
ACOFF=0V

andromedax

R EZ A писал(а):

VL=5V
ACON=0V
MAINPWON=Variable 2.5-4V
PD15 Pin1=Variable 2-3.5

PACIN=0V
ACOFF=0V

Check PD1 for short-circuit.

Post voltage pin 2 & 3 of PU18A.

Check voltage of RTCVREF (3,3v.)

Вложение:

PACIN.jpg

R EZ A

PD1 work correctly
PU18:
Pin1=0V
Pin2=3.3V
RTCVREF=3.3v

andromedax

R EZ A писал(а):

Pin1=0V
Pin2=3.3V

Check PR297, PR295, PR296.

Replace PU18.

Вложение:

vin detector.jpg

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5742 (LA-5893) No turn on [РЕШЕНО]

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