Dell Vostro 15 3568 can't turn on

Model - Dell Vostro 15 3568
Board id - Vegas Turis SKL/KBL 15341-1 91N85

Laptop came with 19V line short. I found the shorted ic PU5301 and replace with good one. For now, when press power button, CPU fan spin for some seconds and then stop. Power comsumption on DC Supply is about 0.180 amp. Need help.

Voltages to ground on coils ...
PL4501 - 5V
PL4502 - 3.3V
PL5101 - 1.2V
PL5301 - 1V
PL5001 - 1V
PL4401 - 0.1V (Without Battery)
PL8501, PL8502, PL8651, PL8601, PL4701, PL4801 - 0V

Resistance to ground on coils ..
PL8501, PL8502 - 11 Ohm
PL8651 - 55 Ohm
PL8601 - 155 Ohm
PL4701 - 5.5 Ohm
PL4801 - 4.1 Ohm

What voltage to ground do you have on pin 1 of PU5301 (PWR_1D0V_PG signal) when the MLB is switched on?

Voltage to ground on pin 1 of PU5301 is 3.3V. I flash some BIOS files and now laptop can't switch on anymore (Even flash again Backup BIOS). 3V 5V is ok. PL5301 is 1V and pin 1 of PU5301 is 3.3V. All other coils are 0V now and can't switch on.

RTC battery removed?

On PL5101 you have a voltage.

For now voltages are on again describe as first post #1. When connect original adapter or DC Supply, power led light show for some seconds and then stop. No cpu fan spin. CMOS battery is installed and have 3.1V.

Measure the voltages on pins 2, 4, 6, 7, 35, 36 of PU4701 (pin 4 if it can be measured with an oscilloscope).

PU4701 pins
Pin 2 - 4.9V
Pin 4 - 2V (i don't have an oscilloscope)
Pin 6, 7, 35, 36 - 5V

Measure the resistances to ground on all coils.

Resistance to ground on coils are
PL4501, PL4502 - above MOhm
PL5101 - 170 Ohm
PL5301 - 28 Ohm
PL8501, PL8502 - 14 Ohm
PL8651 - 57 Ohm
PL5001 - 13 Ohm
PL4701 - 6.6 Ohm
PL4801 - 5 Ohm
PL8601 - 184 Ohm

Measure the voltages to ground on pads 2, 4 on the place of chip U1701 (this chip is factory not soldered to the board).

U1701 pin 2 - 3.3V and pin 4 - 1.0V

Measure the following voltages to ground, when the machine is turned on:
- On pin 2 on the place of resistor R411 (this resistor is factory not soldered to the board).
- On pin 2 of transistor PQ8604.
- On pins 56, 73 of KBC chip.

R411 pin 2 - 1V
PQ8604 pin 2 - 0.3V
KBC pin 56 - 0V
KBC pin 73 - 3.3V

Also measure the voltages to ground on pins 18, 25, 36, 41, 48, 89, 128 of KBC chip, when the machine is turned on.

KBC chip pins
Pin 18 - 1.18V
Pin 25 - 1V
Pin 36 - 3.3V
Pin 41 - 3.3V
Pin 48 - 3.3V
Pin 89 - 3.3V
Pin 128 - 3.3V

The signal "PCH_PLTRST#" from the CPU is missing. The APU hybrid is unfortunately damaged.
You can try to reflow the APU, but it needs to be replaced for the permanent repair.