la f401p not charging battery

[RichBon]

i have these la - f401p motherboard that i am working on. the problem is that it does not charge the battery up it only shows its charging but does not go up. attached is the picture of how it looks. can anyone help me.

[mon2]

1) Confirm that the power adapter @ 90W matches the actual power adapter's markings. Confirm this adapter is suitable to run this logic board.

2) It is possible that the battery may be old or defective. If possible, test with another known good battery or test this battery inside of another working logic board.

3) Remove all power. Meter in lowest resistance mode. Short your meter probes and note the resistance of the shorted probes.

Locate the charger IC @ PU901. With no power to the board / no battery connected; measure the resistance between pins 1 & 2 on this charger IC.

We are confirming the full current resistance path for the battery leg of the circuit. Post the measurements.

[RichBon]

sir should the red prob be on ground to check or red on pin 1 and black on pin 2

[RichBon]

measuring the resistances between the pin 1 and 2 002.2oms
but to ground is 0L for both side

[mon2]

These are good measurements. The total path of the battery charge resistors = 1 ohm + current sense resistor (milli-ohms) + 1 ohm = ~2 ohms.

Configure your meter into DC volts mode -> connect the battery and also the power adapter.

Carefully, measure the voltage to ground of the following signals:

PBAT_CHARGER_SMBDAT
PBAT_CHARGER_SMBCLK

We are checking if either of the above lines is shunted to ground from a defective TVS ESD diode.

[mcplslg123]

PQ4/PQ9-voltage on pin 1/4/8?
PU2,pin3 voltage?

[RichBon]

PQ4 is 19 for both 1and 8 pin4 is 1.7v
and pq9 is 19 and gate is 9.v

[RichBon]

These are good measurements. The total path of the battery charge resistors = 1 ohm + current sense resistor (milli-ohms) + 1 ohm = ~2 ohms.

Configure your meter into DC volts mode -> connect the battery and also the power adapter.

Carefully, measure the voltage to ground of the following signals:

PBAT_CHARGER_SMBDAT
PBAT_CHARGER_SMBCLK

We are checking if either of the above lines is shunted to ground from a defective TVS ESD diode.

all gives me 3.3 volts

[RichBon]

PQ4 is 19 for both 1and 8 pin4 is 1.7v
and pq9 is 19 and gate is 9.v

pu2 pin 3 is 3.3v

[mon2]

PU2 voltage is ok. This component is a high voltage (input) LDO regulator (capable of accepting the power adapter voltage directly for input) and with a fixed 3v3 output rail. All good here.

[RichBon]

Please is there anything else that is not making it charge

[mon2]

Remove all power -> meter in lowest resistance mode. Measure the resistance from the battery connector PBATT1 pins 1-2-3 to the mosfet pins on PQ906. This is to confirm that the EMI filter beads @ PL1 and PL2 are not open circuit.

With the power adapter and battery connected, meter in DC volts mode (20v or higher scale if manual type of meter) - carefully measure the voltage to ground on each leg of mosfet PQ906.

Post each measurement.

[RichBon]

hi thank all you for the support you gave me. I was able to fix the problem. the solution was PQ 906. that was fault. after changing it, it works well

[mon2]

Awesome! Thanks for the update.