ASUS X455L Battery not detected problem.

[bustacaps]

Hello everyone, my problem goes like this... I have Asus X455L laptop. Initial problem was battery not detected so I replaced it with a new battery but still not detected and since it was not detected it was not charging. The battery led(orange) indicator keeps blinking. When pressing power button without plugging the adapter it WON'T turn-on with the new battery installed. But when I plugged the adapter it turned-on immediately(not pressing power button anymore). The laptop has display by the way. Also I noticed the fan spinning fast(I can hear its sound).

The troubleshooting I've done so far are: Software related(not working), Checked the motherboard battery pins voltages pin1&2(+terminal)=0.9V,pin3(SMB0_DAT_CLK_CON)=3V, pin4(SMB0_DAT_BAT_CON)=0V, pin5(P_RTC_LDO3V3)=0V, pin6,7,&8(GND).

Can someone please help or guide me to exactly pin point the bad component?. Because my first thought it was the charger IC(BQ735) but I'm hesitant replacing it. I just want to be sure. Thank you so much in advance!

[mon2]

Re: ASUS X455L Battery not detected problem.

pin4(SMB0_DAT_BAT_CON)=0V

This is not correct for this signal.

Remove all power. Meter in resistance mode.

Check the resistance to ground of this signal. You may have a shorted esd diode on this signal line.

Review the resistance and hunt for an ESD protection diode on this line. If found, remove it off the board and check the voltage again. It should be ~3 volts.

[bustacaps]

Re: ASUS X455L Battery not detected problem.

This is not correct for this signal.

Remove all power. Meter in resistance mode.

Check the resistance to ground of this signal. You may have a shorted esd diode on this signal line.

Review the resistance and hunt for an ESD protection diode on this line. If found, remove it off the board and check the voltage again. It should be ~3 volts.

I have done what you instructed sir. But upon checking with also the guidance of the boardview. The diode connected to that line was PD6001. Most probably that was the esd protection diode but the thing is its NOT THERE.

[mon2]

Re: ASUS X455L Battery not detected problem.

For the same signal, check it's resistance to ground.

Remove all power.

Meter in resistance mode.

Meter probe on this same pin.

Other meter probe to ground.

What is the resistance?

[mon2]

Re: ASUS X455L Battery not detected problem.

See attached.

Between the battery connector and this missing ESD diode network, there should be a series 330 ohm resistor.

Remove all power. Meter in resistance mode.

Check the resistance from the one side of this series resistor and the battery connector.

What is the resistance in ohms ? Measure between the 2 yellow arrows.

[bustacaps]

Re: ASUS X455L Battery not detected problem.

For the same signal, check it's resistance to ground.

Remove all power.

Meter in resistance mode.

Meter probe on this same pin.

Other meter probe to ground.

What is the resistance?

Sorry for the late reply sir,
BTW the resistance between pin4 to GND= 325ohms.

[bustacaps]

Re: ASUS X455L Battery not detected problem.

See attached.

Between the battery connector and this missing ESD diode network, there should be a series 330 ohm resistor.

Remove all power. Meter in resistance mode.

Check the resistance from the one side of this series resistor and the battery connector.

What is the resistance in ohms ? Measure between the 2 yellow arrows.

Yes, there is a 330ohm resistor. It reads 324ohms.

The one side of this series resistor(PR6001) and the battery connector(pin4)=324ohms.

RN3001 is present and not corroded it reads--4k25ohms on those pins you indicated.

PSL8802 to pin4 is 342ohms.

It seems all values are good sir...

[bustacaps]

Re: ASUS X455L Battery not detected problem.

Now I'll try to measure the pin voltages for BQ735 charging ic to see any incorrect output.

Anyone knows, what will be the expected output for each pin?

So that I can compare my reading...