Asus zenbook pro ux535li not charging

[sauce]

Hi,

I bought a dead laptop Asus ux535li : liquid damage (red wine)

There was corrosion on audio chip so i reflow chip.
It was not working (no power) so I check again and there was remaining red wine spots.

So I clean all the area and laptop turns on !

And the battery was charging but it was quite hot I don't know if it's normal.


But now the problem is that the battery is not charging anymore.

And really stranges thinks happen the laptop can run on ac or battery but once stopped it cannot turn on on battery I need to plug charger. After I can remove charger and laptop is running.

Another strange think is under windows 11 if I unplugg charger there is a message on screen that I am on battery but the message alternates with ac mode even if charger is unplugged !

A test on battery says the battery is good.

So what can i check ? Bad bq chip ?

Best regards and sorry for my bad english.

[mon2]

Re: Asus zenbook pro ux535li not charging

Post the markings of the charger (BQ?) IC.

Check the ACOK voltage to ground on the charger IC.

This status pin confirms if the power adapter is acceptable or not.

[sauce]

Re: Asus zenbook pro ux535li not charging

Bq24780S for charging ic.

ACOK was 2.7V when I measure it last time.

[mon2]

Re: Asus zenbook pro ux535li not charging

ACOK voltage is ok if the adapter is connected. It should be 0v with the adapter removed.

Be sure that the adapter is the proper rated model for this logic board otherwise, the CPU speed will be throttled and battery will not be charged.

Check the voltage to ground of ACDRV at the gate pins of the 2 x DCin mosfets. If all is well, the gate voltage should be REGN voltage (6 volts on the charger IC pin) + adapter voltage (~19v) = ~25 volts at the gate pin.

With this boosted gate voltage, the mosfets should turn ON to power the logic board.

You should be able to power the board without the use of the battery. Respectively, if the battery is attached, it should charge unless the battery is defective or there are defective charger mosfets. The BQ charger IC drives a HIGH SIDE and LOW SIDE mosfet. Together, they 'dial' up the battery charge voltage.

That is, the high ~19v from the adapter is lowered down to a safe battery charge voltage.

With the battery & adapter connected, what are the voltage to ground readings on the battery connector? If the battery is heating up, the voltage could be too high or the battery pack itself is defective.

Does Windows detect the presence of the battery ? Is Windows able to show that the battery is charging ? Level of charge, etc. ?

[sauce]

Re: Asus zenbook pro ux535li not charging

On ac the laptop is working fine. The charger is the original one of 150w.

When ac adapter is plugged or unplugged the voltage at battery connector is 12-13v.

If I remove the ac adapter the voltage is the same.

But if i turn off the laptop and let it for few minutes the laptop won't turn on only on battery and the voltage on battery connector is 0v.

I need to plug the charger to turn on the laptop again and i can remove ac adapter the laptop still working fine

Really strange behaviour.

[mon2]

Re: Asus zenbook pro ux535li not charging

Since the battery was getting hot, recommend for you to test with another known good battery. Perhaps someone on Amazon so that it can be tested risk free.

[sauce]

Re: Asus zenbook pro ux535li not charging

Yes it would be great to test with a brand new battery but without buy it

[mon2]

Re: Asus zenbook pro ux535li not charging

That is why I suggested Amazon. Try it and return it if the fault remains the same. Keep it if it works.

[sauce]

Re: Asus zenbook pro ux535li not charging

Ok not a bad idea

I don't understand I just test again and now laptop is charging.

I run 3d benchmark and battery seems to be good.

Maybe it's normal but is there a back cover switch or something like because every time I remove back cover the laptop won't turn on only on battery I need to plug the ac charger for turning it on.

After that I can run on battery, turn it off, turn it on again and all is working fine.