Asus G750JW Rev2.1 works on battery but not charger

[alekk89]

Hello guys,
A friend of mine tried to replace his thermal compound and i don't know exactly what he did but PR8842 (10ohm resistor on the charger line) was burned. I replaced it but still doesn't turn on charger only.
After the resistor is the charging ic, any idea how to check if it works properly?

[ktmmotocross]

Re: Asus G750JW Rev2.1 works on battery but not charger

that 10 ohm resistor have high amperage so u must have short after him

[alekk89]

Re: Asus G750JW Rev2.1 works on battery but not charger

Since it works on battery only i assume the problem is somewhere with the charging circuit. After the resistor comes directly the charging/power management ic.
Any idea where should i look for short?

[Techtiger]

Re: Asus G750JW Rev2.1 works on battery but not charger

Since the Mob Working on Battery first check your first 2fets and the CLR Resistor Voltage, for the Fets test all legs Voltage May be your are not getting the Gate pass for the moment don’t change any components unless your sure, request the board View in Schematic Section

[alekk89]

Re: Asus G750JW Rev2.1 works on battery but not charger

PQ8801 -
pin 1-3 0.5v
pin 4 - 5mV
pin5 - 19.7V

PQ8802 -
pin 1-3 0.5v
pin 4 - 5mV
pin 5 - 220mV

Charger only connected, no battery

*I have boardview, i don't have the schematics though

[ktmmotocross]

Re: Asus G750JW Rev2.1 works on battery but not charger

charging line did not comes directly to charger ic. it comes THROUGH that resistor to main 19V line. charger ic is just connected to that resistor to measure current by measuring voltage drop on him

did u check resistance to ground on that resistor?

[Techtiger]

Re: Asus G750JW Rev2.1 works on battery but not charger

PQ8801 -
pin 1-3 0.5v
pin 4 - 5mV
pin5 - 19.7V

PQ8802 -
pin 1-3 0.5v
pin 4 - 5mV
pin 5 - 220mV

Charger only connected, no battery

*I have boardview, i don't have the schematics though

Upload the boardview pin 4 must be the Gate, Voltage on the Gate is too low

[SMDFlea]

Re: Asus G750JW Rev2.1 works on battery but not charger

Post #13 for the boardviews: https://www.badcaps.net/forum/showth...ghlight=G750JW

[Techtiger]

Re: Asus G750JW Rev2.1 works on battery but not charger

Post #13 for the boardviews: https://www.badcaps.net/forum/showth...ghlight=G750JW

Thanks SMDflea

[Techtiger]

Re: Asus G750JW Rev2.1 works on battery but not charger

now test voltage on PU8800 pin 4 ACDRV 20 to 25V ?
voltage PR8809 both sides ? PC8805 both sides ?

[alekk89]

Re: Asus G750JW Rev2.1 works on battery but not charger

now test voltage on PU8800 pin 4 ACDRV 20 to 25V ?
voltage PR8809 both sides ? PC8805 both sides ?

PR8809
Pin1 - <20mV
pin2 - <10mV

PC8805
Pin1 - 19.7V
Pin2 - <20mV

PU8800 pin4 - <10mV

charging line did not comes directly to charger ic. it comes THROUGH that resistor to main 19V line. charger ic is just connected to that resistor to measure current by measuring voltage drop on him

did u check resistance to ground on that resistor?

I checked for short to ground on both sides of the resistor before replacing, no short.

[Techtiger]

Re: Asus G750JW Rev2.1 works on battery but not charger

PR8809
Pin1 - <20mV
pin2 - <10mV

PC8805
Pin1 - 19.7V
Pin2 - <20mV

PU8800 pin4 - <10mV

PU8800 pin 4 volage must be +20V ok now test same IC pin 20 1 2 5 6 16 and pin 4 Ohms

[alekk89]

Re: Asus G750JW Rev2.1 works on battery but not charger

PU8800
All resistance measured directly on the pins to gnd

Pin1 - 2.46k
Pin2 - 2.46K
Pin4 - 0L
Pin5 - 0.66M
Pin6 - 17.2K
Pin16 - 135K
Pin 20 - 0.484k

[Techtiger]

Re: Asus G750JW Rev2.1 works on battery but not charger

PU8800
All resistance measured directly on the pins to gnd

Pin1 - 2.46k
Pin2 - 2.46K
Pin4 - 0L
Pin5 - 0.66M
Pin6 - 17.2K
Pin16 - 135K
Pin 20 - 0.484k

Same pins Voltage's expect pin 4

[alekk89]

Re: Asus G750JW Rev2.1 works on battery but not charger

PU8800

Pin1 - 350mV
Pin2 - 350mV
Pin5 - 20mV
Pin6 - 2.6V
Pin16 - 11.5V
Pin 20 - 18.9V

[Techtiger]

Re: Asus G750JW Rev2.1 works on battery but not charger

pin 1 ACN 20.3
pin 2 ACP 20.3
pin16(regn) should be 6V
pin 6 ACDET@2.87
pin 5 ACOK@0V
pin 4 ACDRV should be 19v+6v approx
second DC-in MOSFET (towards the system side) test for shorted (gate/source/drain) with the help of multimetre

[on/off]

Re: Asus G750JW Rev2.1 works on battery but not charger

HPA02196RGRR or BQ735 need acok high / 3.3V

only ac_in_oc# required low signal / 0V

[mcplslg123]

Re: Asus G750JW Rev2.1 works on battery but not charger

HPA02196RGRR or BQ735 need acok high / 3.3V

only ac_in_oc# required low signal / 0V

correct

[Techtiger]

Re: Asus G750JW Rev2.1 works on battery but not charger

correct

HPA02196RGRR or BQ735 need acok high / 3.3V

only ac_in_oc# required low signal / 0V

thanks

[alekk89]

Re: Asus G750JW Rev2.1 works on battery but not charger

No short on either of the mosfets (PQ8801, PQ8802)