ASUS FX507v No Power

[noipi]

I have ASUS laptop FX507 when i plug-in the charger nothing happens or the amperes not even raising up it stays to 19.5v(SETTINGS). I decided to disassemble the back case to check the voltages first. I found out that when i test the current sensing resistor for voltage it was fluctuating voltages(3volts to 5v then loop), i checked the voltages of the BQ24800 Battery Charge Controller:..i started with the pin 1 and the results are:
1. 3.5v to 3.9v
2. 3.5v-3.9v
3. 0.3v-1.4v
4. 0.3v-1.2v
5. 0v
6. 2.6v
7. 0v
8. 0v
9. 1.6v
10. 0v
11. 0.04v-1.1v
12. 0.2v- 1.2v
13. 0.2v
14. 6v
15. 0v
16. 0v
17. 0.2v
18. 0.2v
19. 0.2v
20. 0.2v
21. 0.2v-0.9v
22. 0v
23. 0v
24. 6v
25. 6v
26. 0.2v
27. 0.2v
28. 19.5v

i Need help, Any idea before i change anything or i suspect the charging IC to be replace, i test the 1st and 2nd mosfets from chrging pin it is not shorted or leaky.. thank you.

[mon2]

ACDRV pin #4 is not boosted to the expected ~25v so there is a fault in the power path.

The DCin mosfets are still suspects. Remove all power. Meter in resistance mode.

Measure each of the DCin mosfets:

source / drain
source / gate
gate / drain

Post each measurement. Start with the 2nd DCin mosfet (as per sticky above on charger circuits by piernov).

[noipi]

ACDRV pin #4 is not boosted to the expected ~25v so there is a fault in the power path.

The DCin mosfets are still suspects. Remove all power. Meter in resistance mode.

Measure each of the DCin mosfets:

source / drain
source / gate
gate / drain

Post each measurement. Start with the 2nd DCin mosfet (as per sticky above on charger circuits by piernov).

thank you for the very fast reply..i will test today what you mention. i will update later today.

[mcplslg123]

Resistance to GND on Current Sensing Resistor?

[noipi]

ACDRV pin #4 is not boosted to the expected ~25v so there is a fault in the power path.

The DCin mosfets are still suspects. Remove all power. Meter in resistance mode.

Measure each of the DCin mosfets:

source / drain
source / gate
gate / drain

Post each measurement. Start with the 2nd DCin mosfet (as per sticky above on charger circuits by piernov).

Both DC-in MOSFET first and second got high resistance ranging Kohms to Mohms when reading for source/gate ; gate/drain. no low resistance got from this side and around the Charging ic mosfets..

[noipi]

Resistance to GND on Current Sensing Resistor?

i try to read the resistance to ground on Current sensing resistor is 20Mohms, seems to be good.

[noipi]

this time trying to test all mosfets and capacitors that is shorted...motherboards seems so clean no sign of burnt or bad components...still checking this time.

[mon2]

first and second got high resistance ranging Kohms to Mohm

post the requested measurements.

[noipi]

here is the Readings of the DCIN mosfets before the Current Sensing resistor

the first dcin mosfet measure by resistance mode:
source/drain 8.8Mohms (probe RED BLK)
source/gate 1.3Mohms (probe RED / BLK)
gate/drain 14.34Mohms (probe RED / BLK)

the 2nd DCIN mosfet measure:
source/drain 7.8Mohms (probe RED BLK)
source/gate 1.3Mohms (probe RED / BLK)
gate/drain 14.17Mohms (probe RED / BLK)

[noipi]

tried to find SCHEMATIC diagram or boardview but i cannot see.

[Dcortest]

Maybe this can help

Link to boardview --> https://www.badcaps.net/forum/troubl...%CC%87ew-needs

[noipi]

thank you Dcortest

[noipi]

Thank you to all for the help, specially to Dcortest for the Boardview that really solve the circuit. i change the 2 mosfets that are P-mosfet and N-mostfet connected to the line of Charging IC.

[ethics]

Nice job! Where did you buy them?

[mon2]

Digikey should have valid replacements. Mobile Sentrix Canada also stocks assorted mosfets.

Post the full part numbers of the mosfets you wish to replace.