Lenovo IdeaPad Slim 3 15IAN8 won´t power on after power off without AC charger plugged in

[WTFRules!]

Hi!

I´ve this Lenovo IdeaPad Slim 3 15IAN8 with mainboard (KS480 / KS580) NM-E901 Rev 1.0
I receive it for repair from another shop and it had shorted EC IT8227VG-256
After replacing it and programming it with SVOD 4 (wich is new to me as I bought it in this week) the laptop is working fine now... BUT

Once power off from windows, it will not turn on again. When off and the power on button is pressed, a white led turns on and that´s it.
But if you plug the charger, then all the keyboard LEDs will lit and then you get image on screen and it boots normally.
After this, you can use it with battery normally, if you restart it, it restarts fine, and if you close the lid and open it back, it still works like a charm.

The problem is turning it off and then back on with battery, you only get a white LED on near the power button. Plugging the AC charger back again, it will make it turn ON like nothing happens.

I´m attaching a boardview I got from this forum as reference as i don´t have the schematics.

All measures from battery seems fine.
No shorts detected.
Also I updated UEFI firmware and ME from latest files from LENOVO, the issue remains the same.

Any help is appreciated.


Thanks!

[mon2]

Review the dual diode that often feeds the vcc pin of the charger ic. Usually on the BQ chips, this dual diode will have one leg to the battery and other to the raw adapter voltage. Confirm this dual diode is not defective.