Asus X541uv rev2 Always charging

[tomimc]

Hi i have this board. With battery connected the laptop dont turn on.
Without battery, the board turn on but the board thinks always have the battery conneced. The charging light is on(without battery) and the mosfet are working trying to charge the battery (12v on coil, battery disconected). Even Windows says battery 100% when i open the battery icon.
I changed the bq but same behaviour
Can any help me?

[mon2]

Re: Asus X541uv rev2 Always charging

OMG - your board needs to mate with the boards that do not charge and breed.

Which BQ chip is onboard ? Post the topside markings.

BQ chips like to use 2 x DCin N-channel mosfets. As per @Pienov's sticky (buns?) above, the 2nd mosfet often leaks and causes such faults.

You will need to check if the DCin mosfets are leaking using a resistance check.

Remove all power. Meter in resistance mode.

Measure the resistance across the mosfet pins.

Source (1-2-3) & drain (5-6-7-8)
Source (1-2-3) & gate (4)
Gate (4) & drain (5-6-7-8)

Post each measurement for each DCin mosfets. These mosfets should be close to the power adapter connector and the charger IC.

[tomimc]

Re: Asus X541uv rev2 Always charging

Hahaha i can share board's whatsapp number to meet boards dont want to charge

Mosfets are not in short, PQH8106 PQL8107, resistances are high. I just changed just in case.
What i found was some liquid damage, i just saw it on resistances rn2502, the signals are PM_RSMRST#_PCH and DPWROK_EC even a line was broken. Now is clean and the line is ok.

Now board turns on with and without battery, and charge battery ok but without battery charge battery too and the light is still always on.

What i found is the line TS1#_BAT_CON is always in 0v, dont know if without battery must be in high.
P_CHG_BATPRESS#_10 on bq is always 0v too, with and without battery.

How this board know when to charge the battery?

[tomimc]

Re: Asus X541uv rev2 Always charging

i forgot to say bq is BQ24780

[mon2]

Re: Asus X541uv rev2 Always charging

Remove all power and check the resistance to ground of

P_CHG_BATPRESS#_10.

It is possible that a local pull-up resistor is missing.

[tomimc]

Re: Asus X541uv rev2 Always charging

P_CHG_BATPRESS#_10. 10k to ground
that line is connected to ec BAT_IN_OC# with a 10k resistor conected to ground.

The board with battery works perfect. Charge to 100% and stop charging at 100%. The only problem is without battery, so maybe i go to assemble the laptop couse with battery works ok.

Anyway, I would like to understand how the board detects the battery

[mon2]

Re: Asus X541uv rev2 Always charging

The BQ24780 data sheet will offer in depth details of the charging process.

Some quick points are:

1) adapter is detected - check ACDET

2) adapter is ok - check ACOK

3) battery is present - check battery detect pin

4) if adapter is attached, battery mosfet that is used to power the board will be OFF. Adapter will power the board. Check the voltage on each pin of the battery mosfet.

5) charger mosfets to charge the battery will enable

6) suggest for you to measure the voltage to ground of each pin on the charger IC.

Measure with adapter and battery connected.
Measure with adapter removed but battery connected.

Post each batch of measurements.