Lenovo V14-ARE Auto Charging

[michi.boy]

Hi,

I have a Lenovo V14-ARE that charges by itselt. even without charger plugged in.

Laptop is in normal use. if you put charger the batt. percentage increase. if plugged out will decrease.
There is also a response when charger is plugged in,

tried changing battery
updating drivers and bios.

[mon2]

Good on the ACOK testing.

Remove all power. Meter in diode mode.

Test the dual diode @ PD201.

Place the red meter lead on pin # 2 of PD201. Black meter lead on pin # 28 of the charger IC. The meter should conduct. What is the voltage measurement on the meter? Again, no power / no battery to the logic board when testing in this diode mode.

Repeat but reverse the color of the leads (black on pin # 1 / red on pin # 28) - the diode should block. Confirm this.

Repeat with pin # 3 of PD201 and pin #28 on the charger IC. These tests are to confirm that PD201 is not leaking.

[mon2]

To confirm, if you unplug the external power adapter, the Windows status will still show that the adapter is plugged in and charging the battery?

Sounds like the battery voltage is leaking backwards through the power adapter power path (PQ201 & PQ202) and ending up fooling the ACDET pin 6 on the charger IC.

Confirm this thought by measuring the voltage on pin # 6 of PU201 (BQ chip) with the power adapter attached; then again with this power adapter removed. When the power adapter is removed, you should have 0v on pin # 6. If you do not, then the 2 above mosfets are suspects and are leaking.

[michi.boy]

To confirm, if you unplug the external power adapter, the Windows status will still show that the adapter is plugged in and charging the battery?

Yes,

Confirm this thought by measuring the voltage on pin # 6 of PU201 (BQ chip) with the power adapter attached; then again with this power adapter removed. When the power adapter is removed, you should have 0v on pin # 6. If you do not, then the 2 above mosfets are suspects and are leaking.

Pin 6 on BQ chip have 2.8v when plugged in and goes to 0v when out.

tried also changing the chip with no luck.

[mon2]

What is the voltage to ground of ACOK pin 5 of PU201?

Be sure this open-drain pin is not floating and it must have a pull-up resistor to park this pin to a logic '1' but should be a logic '0' when the adapter is removed.

Also, measure the voltage to ground of CMSRC pin on PU201 with the adapter; then again without the adapter.

[michi.boy]

What is the voltage to ground of ACOK pin 5 of PU201?

3.3v
if removed goes 0v then up to 3.3v again

Also, measure the voltage to ground of CMSRC pin on PU201 with the adapter; then again without the adapter.

19v plugged
0.001 something without

still looking for that 10k resistor. 😄

[mon2]

ACOK should be logic low when the adapter is removed to denote the adapter is absent or not OK.

This is an open drain signal so if logic high, then the charger ic is floating the line like an open switch and the external pull up is parking the line.

Test by shorting this ACOK line to ground with a piece of wire- could solder it for now. Then power up again to test.

Does the fake charging stop?

[michi.boy]

Test by shorting this ACOK line to ground with a piece of wire- could solder it for now. Then power up again to test.

Does the fake charging stop?

Yes, it stop. But the power indicator light is now blinking.

Tried to put the adapter, No response.

[mon2]

Good on the ACOK testing.

Remove all power. Meter in diode mode.

Test the dual diode @ PD201.

Place the red meter lead on pin # 2 of PD201. Black meter lead on pin # 28 of the charger IC. The meter should conduct. What is the voltage measurement on the meter? Again, no power / no battery to the logic board when testing in this diode mode.

Repeat but reverse the color of the leads (black on pin # 1 / red on pin # 28) - the diode should block. Confirm this.

Repeat with pin # 3 of PD201 and pin #28 on the charger IC. These tests are to confirm that PD201 is not leaking.

[michi.boy]

Repeat with pin # 3 of PD201 and pin #28 on the charger IC. These tests are to confirm that PD201 is not leaking.

Pin 3 reads 2.8xx. something,

I replaced the diode and it's working fine now.

Thank you very much sir for the time, troubleshooting guide.

Very much appreciated.

i wouldn't have done this without the support.

hope to have help in the future. 😁

and also sorry for the english, i'm also not good at it. 🤣