Acer Aspire 5742ZG working on battery only!

[Frenk7]

Acer Aspire 5742ZG-P612G50Mnkk
Motherboard:
NEW70 LA-5891P
Rev : 1.0

I have laptop that was in contact with liquid. It is working on battery only, if i plug in charger without battery nothing happens. I have check the charger it is ok (19V). I have check first 2 mosfet, on first i have on input 19V, on output 18.58V, second mosfet, input is 18.58V and on the output i have 8,3V. I have try replaceing second mosfet and problem was the same, so i shorted second and now i have 18.58V on main power rail, i have 3.3V rail and 5V rail, and it still works only on battery. I have try with 19V from power supply on output of second mosfet and it takes only 0.02A so i think i have no short on main power rail. I have no more ideas, and the sad part is that i have bordview and schematic...

HELP PLEASE

[ktmmotocross]

Re: Acer Aspire 5742ZG working on battery only!

measure all pins on charger ic for voltage and for its resistance to ground, without that jump/original state/ and without battery

and NEVER jump that two mosfets until u check all highside mosfets for short

[Frenk7]

Re: Acer Aspire 5742ZG working on battery only!

Tell me please if i'm right, that should be ISL6251A ic?

[ktmmotocross]

Re: Acer Aspire 5742ZG working on battery only!

put it to google and u easy find its datasheet.

[Frenk7]

Re: Acer Aspire 5742ZG working on battery only!

I hope i have manage to upload the pictures of iz

[Techtiger]

Re: Acer Aspire 5742ZG working on battery only!

Voltage in pin4 PQ51 ? pin 4 must be 8.14V with 19V in
Voltage in PR371 PACIN both sides ?
Voltage in PQ65 pin 2 ACOFF

[Frenk7]

Re: Acer Aspire 5742ZG working on battery only!

First pictures with voltages of charging ic:

[Frenk7]

Re: Acer Aspire 5742ZG working on battery only!

ok, techtiger here are voltages:

PQ51 PIN 4: 18,69V
PQ52 PIN 4: 18,69V

PQ65 ACON: 0.030V
ACOFF: 0.00V

PR371 PACIN: 0.030V
ACON: 0.000V
The measurement are taken with both mosfet PQ51 and PQ52 soldered back on

[ktmmotocross]

Re: Acer Aspire 5742ZG working on battery only!

check page 8

https://cdn.badcaps-static.com/pdfs/...da79b1c524.pdf

[Techtiger]

Re: Acer Aspire 5742ZG working on battery only!

now test voltage PD18 both sides DCIN (19V) is the supply for PU17 with out battrey

[Frenk7]

Re: Acer Aspire 5742ZG working on battery only!

I am looking at page 8 and i see that my voltage readings are all off, but i think that is because i don't have good input voltage. Am i right?

[Frenk7]

Re: Acer Aspire 5742ZG working on battery only!

I don't see pd18, i have pc252 and pq54 on DCIN.
And on PQ54 i have:
Pin 1 - DCIN: 0.055V
Pin 2 - N47340532: 8.3V
Pin 3 - P3: 8.3V

[Frenk7]

Re: Acer Aspire 5742ZG working on battery only!

Here is schematic and boardview, if someone don't have it. Thanks, all help is appreciated

[ktmmotocross]

Re: Acer Aspire 5742ZG working on battery only!

I am looking at page 8 and i see that my voltage readings are all off, but i think that is because i don't have good input voltage. Am i right?

u r right. trace it

[Techtiger]

Re: Acer Aspire 5742ZG working on battery only!

Here is schematic and boardview, if someone don't have it. Thanks, all help is appreciated

the Schematic is diffrent your Mob is Acer Aspire 5742ZG ?

[Techtiger]

Re: Acer Aspire 5742ZG working on battery only!

I don't see pd18, i have pc252 and pq54 on DCIN.
And on PQ54 i have:
Pin 1 - DCIN: 0.055V
Pin 2 - N47340532: 8.3V
Pin 3 - P3: 8.3V

Pin 3 is connected with PQ52 out put P3 terminal that's why low voltage of 8.3V it should be 19V but PQ52 is not switching on according to the Boardviewer.
the Schematic i have send and your Boardviewer dosen't match also what is you Mob number compal-la XXXX ?

[Frenk7]

Re: Acer Aspire 5742ZG working on battery only!

Yes, it is, but motherboard is NEW70 LA-5891P
Rev : 1.0, and i haven't anything wrong with schematic

[Frenk7]

Re: Acer Aspire 5742ZG working on battery only!

I mean to say, i haven't see anything wrong with this schematic

[shandybass]

Re: Acer Aspire 5742ZG working on battery only!

Check for VS rail voltage, pin 1 of PC213. If ok then check voltages on PU18A

[Frenk7]

Re: Acer Aspire 5742ZG working on battery only!

PC213:
P1-18,41V
P2-0.0V

PU18:
P1-0.03
P2-3.26
P3-3.52
P4-gnd
P5-3.9-4.2
P6-3.23
P7-4.2-4.7
P8-18.46