DELL INSPIRON 7306 2in1 (Mobo: HELLCAT 13 TGL MB, 19827-1) - stuck on 5V and 310mA

Hello Everyone,
I am looking for help to solve the problem.

5V line has been shorted due to water damage to connector on daughter board (Audio, USB, CMOS Battery). Shorted voltage was 5V_S5. After disconnecting daughter board short has gone but laptop in not able to boot.

When I plug power to USB-C value goes to 19.6V and 70mA but after 10 seconds goes down to 5V and 310mA and stays on that level. Power LED blinks once and fan does not spin at all. When I press power button exact the same scenario happens again.

All voltages except CPU are present. It looks like one of the components using 5V_S5 has gone faulty. This is preventing power voltage to stay at level of 20V.
CPU coils resistance is 46ohm so there is no short circuit.
Thank you,
Regards,
Rafal

Measure the resistance to ground on pin 26 of PU4601.

Hello Matic,
Thank you for your help.
I have measured required resistance to ground on pin 26 of PU4601 - 75kΩ.
Regards,
Rafal

RafiManch написав:5V line has been shorted due to water damage to connector on daughter board

Hello!
Was the motherboard also in contact with the liquid?
If, so post a clear pictures of spilled areas of the motherboard.

Set your multimeter to the diode test mode and measure the voltage drops to ground on pins 1, 2, 4, 5, 7, 8, 9, 10 of connector IOBD1.

Hello Matic,
The only water damage what I have found was connector on daughter board:


I have traced damaged area back to IOBD1 connector and it was pin 17,18 and 19 (5V_S5).
The only other ones affected could be pin 16 (3D3V_S5) and pin 20 (3D3V_AUX_S5).
I hope additional information will help to narrow the search.
I have measured all required:
1 (0.33V), 2 (0.33V), 4 (0.81V), 5 (0.81V), 7 (0.76V), 8 (0.89V), 9 (0.84V), 10 (0.86V) of connector IOBD1.
Thank you for your continuous help.