A1707 820-00928 not turning on when battery connected - liquid damage

Hallo and thank you for your time, I have a Macbook Pro A1707 with liquid damage. After replacing three CD3215 chips, the laptop now turns on and works fine when connected to the power supply, but only if the battery is disconnected.
When I connect both the power supply and the battery, the Macbook turns on only when I plug in the power adapter. However, the internal display does not turn on, and macOS does not detect it - only the external display works. Additionally, if I disconnect the power supply while the laptop is on, it shuts off by itself after approximately 30 seconds.

If I try to power it on using the battery alone, it does not turn on at all. The battery is brand new.

I have already changed the ISL9239HI (U7000) but it wasn't the issue.

PPBUS_G3H_R 12.83v
SMBUS_SMC_5_G3_SDA 3.3v
SMBUS_SMC_5_G3_SCL 3.3v
PPBUS_G3H 12.6v
PP3V3_GH3 3.4v
PM_EN_P3V3_G3H_R 5.1v
PP3V3_UPC_TA_LDO 3.376v
PP3V3_UPC_TB_LDO 3.381v
PP3V3_UPC_XA_LDO 3.378v
PP3V3_UPC_XB_LDO 3.380v
PP1V8_UPC_LDOD 1.8v
PM_BATLOW_L 0v
3V3_SUS 0v
PM_DSW_PWRGD 0v
S5_PWRGD 0v

Any insights on what could be causing this issue? Thank you

First of all, welcome to the forum!

Which areas have been affected by liquid spill?

Check resistance (ohm scale) over C7020/23.
Also check diode mode to ground on SCL/SDA lines of battery bus.

2informaticos said:

First of all, welcome to the forum!

Click to expand...

Thank you!

2informaticos said:

Which areas have been affected by liquid spill?

Click to expand...

2informaticos said:

Check resistance (ohm scale) over C7020/23.
Also check diode mode to ground on SCL/SDA lines of battery bus.

Click to expand...

C7020
resistance between pin 1 and 2 : 9.6ohm
C7023
resistance between pin 1 and 2 : 8.3ohm

Diode mode to ground
SMBUS_SMC_5_G3_SDA : 0.489
SMBUS_SMC_5_G3_SCL : 0.476

Thank you

The board looks really bad.
You may have more chips affected by corrosion.
Possibly some traces and pasive components too.

Diode mode readings on SCL/SDA lines should very similar.
You can compare with an working board.

2informaticos said:

The board looks really bad.
You may have more chips affected by corrosion.
Possibly some traces and pasive components too.

Diode mode readings on SCL/SDA lines should very similar.
You can compare with an working board.

Click to expand...

I have another non working board with a different issue but not liquid damaged it's values are :
SMBUS_SMC_5_G3_SDA : 0.452
SMBUS_SMC_5_G3_SCL : 0.455
Then following the SDA/SCL rails I've found they are connected on U5850 ( TMP461 ) which is in the area where liquid spilled.
I removed TMP461 from the board, I will change it with a new one. Let's see what happens

Thank you

Please, write directly into bottom reply box, instead of clicking reply button.
I don't see any reason to quote an entire post, visible few centimeters above...