ASUS x542U (Main x542UQ rev 2.0) Not Charge Battery (work only whit ac adapter)

Good afternoon friends of the forum. This laptop enters me with the defect that works by itself with the adapter connected, if the disconnection turns off. The battery tells me that it is charging and is 80% but it always remains stuck on that percentage. My colleague brings me another original new asus battery, I connect it but always the same problem. With the original battery, it remains stuck at 35% charge.
I tried to replace the ic charger pu8901 (BQ24780S) but the same defect. I made the measurements on the battery connector:
With ac Adapter connected:
PIN 1 0,93V
PIN 2 0,93V
PIN 3 3,27V
PIN 4 3,27V
PIN 5 0V
PIN 6 0V
PIN 7 GND
PIN 8 GND

Meeasure without ac adapter (only battery):

PIN 10,28V
PIN 2 0,21V
PIN 3 0V
PIN 4 0V
PIN 5 0V
PIN 6 0V
PIN 7 GND
PIN 8 GND

Cześć,
sprawdź w ustawieniach BIOS czy nie jest przypadkiem włączone wydłużona żywotność baterii.

//EDIT:
W Samsungach jest to w zakładce Advanced ustawienie "Battery Life Cycle Extension" - aby bateria się ładowała do 100% należy ustawić na DISABLED.

Hi,
check the BIOS settings to see if the extended battery life is on by accident.

// EDIT:
In Samsung it is in the Advanced tab the "Battery Life Cycle Extension" setting - to charge the battery to 100% it must be set to DISABLED.

I thank you for the answer but the problem is not because it remains at 80% (from the bios there is no voice like in samsung to increase the battery life cycle) but the battery is not recharged and if I disconnect the power supply, the computer shuts down with the battery inserted. It seems that the charging circuit is not working, maybe some sense resistance or some mosfet that is not working. I did a check in the mosfets and they are not short (checked between drain and source, no short)

Measure the resistance to ground on pin 6 of battery connector.

Measure the resistance to ground on pin 6 of battery connector.

Hi matic,
no measurement, open circuit

You have most likely "opened" a screw hole (picture below). This two pads should be shorted otherwise the battery will not work.

Thanks for the answer Matic, honestly they had disassembled it from colleagues from another laboratory, Maybe if you make a bridge from pin 6 to GND it should go right?

robgerr napisał(a):Maybe if you make a bridge from pin 6 to GND it should go right?

Yes, exactly.

Hi Matic, I'll update you on the situation, I tried to jumper the pin 6 to gnd, the battery is activated but practically powers the mainboard but is not recharged. I also found an open hole, but in the chassie there is no thread for a screw, as if it were only a predisposition but not implemented. I have also bridged the hole but the same defect. I also noticed that when I unplug the power supply, the charging LED remains on, as if a signal is coming up that is charging even if it isn't. Is there any other test I could do?
Looking at the boardview I notice that the pin6 of the battery connector and the character # as if it were a predisposition.
I'll send you the photo of the boardview

Measure the voltages to ground on all pins of battery connector, when the machine is turned on with battery only (without power supply connected).

Thank's Matic
Test with jumpered hole (PIN 6 to GND)
only battery, machine turned on
Pin 1 7.8 V
Pin 2 7,8V
Pin 3 3,30v with oscillation
pin 4 3,30v with oscillation
pin 5 0,20 with little oscillation
pin 6 jumpered to gnd
pin 7,8 gnd

Install a Battery Mon software and post a screens of "Battery Info" in the following cases:
a) Machine turned on with connected battery only (without power supply).
b) Machine turned on with battery + power supply connected.

a) Machine turned on with connected battery only (without power supply).

b) Machine turned on with battery + power supply connected

It is always charging even without the power supply

Please, post the same screens again, this time with a genuine Asus battery.

Sorry Matic but this is a original battery Asus

robgerr napisał(a):My colleague brings me another original new asus battery, I connect it but always the same problem.

If you have an option, test your battery on another machine.

Hi Matic, thank you for your help, practically then I solved the problem of recharging by resoldering the pins around the ic charger. Works perfectly and laptop delivered to the customer. Thank you very much