Asus UX534F Not charging.

[ronaldopdias]

Hi everyone.
I need some help, please.
This laptop turns on but doesn't charge the battery.
Works on battery and on charger.
No liquid.
Tested with 3 different batteries and same results.
It charges for 5 seconds after plugging the charger with charger drawing up to 60W (on the battery coil it measure 16.5V), but then charging light starts to blink orange and it drops to 8W (Battery coil 15.4V) and voltage on the battery coil drops to the battery voltage.
For now I just replaced the BQ chip, but the issue still there.
Appreciate any help.

[mon2]

Which charger IC is onboard? Link a schematic if available.

Are the batteries the proper ones for this laptop? Known good?

Suggest to remove all power. Meter in resistance mode. Measure the resistance across the battery current sense resistor path but directly on the charger IC. Compare this full path resistance to the schematic values (if available) or study the reference design of the charger IC datasheet. If the full path resistance is not close to the reference value, the charger IC may be turning off this power path.

[ronaldopdias]

I tested the original battery again and it charges fine.
Any other Chinese battery the laptop refuses to charge.
Schematics are here:
https://www.badcaps.net/forum/troubl...x534ft-rev-2-1

All 3 Chinese battery are shown as 100% on the NLBA Laptop Battery Analyzer with EV2400 device.

[mon2]

Remove all power. Meter in resistance mode.

Measure the resistance between pins 19 & 20 on PU8900. Directly at the charger IC pins.

The full path resistance should be ~20 ohms. Confirm it.