Acer Nitro 5 AN515-57-536Q not charging

[Wang Tingting]

I am trying to fix a Acer Nitro 5 AN515-57-536Q not charging issue, the laptop can boot from battery, adaptor or both. The battery LED is solid orange, but it doesn’t charge. The battery report from win11 looks normal, the acer care
report is also good for battery.

Following https://www.badcaps.net/forum/troubl...arging-circuit,

• DCIN/VCC: 19.1
• ACIN/ACDET: 3v
• REGN/VDD: 6v
• CMSRC : 19v
• ACOK: 3.3v
• ACDRV: it is 19v, not 25V(when charging, the ACDRV is 25v)

Test with a 65w charger, it started charging, the adapter vintage is around 17v when output was around 60w, after battery charged to 56%, the vintage was back to 19.7v and stoped charging.
Suspect some damaged passive component, Anyone has an idea about what can be the cause ?

[mon2]

• ACDRV: it is 19v, not 25V(when charging, the ACDRV is 25v)

Often indicates that the DCin mosfets are the suspects. Remove all power. Meter in resistance mode.

measure the resistance across the DCin mosfets (start with the SECOND one in the DCin path):

source / drain
source / gate
gate / drain

Post each measurement in ohms. Repeat with the first DCin mosfet. As per the charger bible by piernov (see above stick) - the 2nd DCin mosfet often gets nuked.

[Wang Tingting]

My bad, the ACDRV is 19v. BATSRC, Connect to the source of N-channel BATFET. BATDRV voltage should be 6 V above BATSRC to turn on BATFET. I got 15.45v for both, the battery vintage, so the BATFET is not on.

datasheet for bq24780S

BATSRC: 17 Connect to the source of N-channel BATFET. BATDRV voltage is 6 V above BATSRC to turn on BATFET.

BATDRV: 18 Charge pump output to drive N-channel MOSFET between battery and system (BATFET). BATDRV is shorted to BATSRC to turn

off BATFET.

[Wang Tingting]

When battery only, BATSRC is 16, BATDRV is 21, so BATFET is on. plug in the power adaptor, the BATDRV changed to 16v, so the BATFET is off.
Maybe the battery is bad or adaptor?