Acer Predator PH317-52 DH5VF LA-F952P REV 1.0N - brak obrazu, resety podczas startu

Witam, dotarł do mnie laptop Acer Predator na płycie DH5VF LA-F952P 1.0N z procesorem SR3YY (Intel Core i7-8750H) i grafiką N17P-G1-A1
Znalazłem na początku problem z upalaniem się rezystora PR8112 (5,1 Ohm) w obwodzie drivera PU8102 (RT9610CGQW)
Wymiana rezystora skutkowała zawsze jego ponownym uszkodzeniem (zwiększeniem jego rezystancji do rzędu kilkudziesięciu kOhm)
Wymieniłem driver PU8102, wspomniany rezystor PR8112, towarzyszący mu kondensator PC8112 i mosfet PQ8101, sterowany przez ten driver.

Płyta zaczęła startować, ale po wentylatorach widać, że resetuje się na okrągło.
Rezystancje na cewkach procesora:
PL8107 = 4,2 Ohm
PL8101, PL8306, PL8305, PL8106 = 2 Ohm
PL8301 = 14,4 Ohm

Pozostałe cewki:

PL502 = 47 Ohm
PL602 = 95 Ohm
PL301 = 12,5 MOhm
PL402 = 3,8 kOhm
PL404 = 15k Ohm
PL302 = 101 Ohm
PL1501, PL1504 = 1,2 Ohm

Bios przeprogramowany, również bez zmian. Czyżby 2 Ohmy na tym procku to za mało i to on jest problemem?
Może pomoże ktoś w diagnozie?

Edit: podczas startu, prąd wskakuje na około 700mA i oczywiście spada do zera. na termowizji widać, jak startuje mostek, grafika, a procesor startuje tylko w jednym narożniku, reszta procesora martwa (nie dostaje pewnie zasilania).
Sygnał PWM 2,5V (zmierzone w czasie tej 1 sekundy, gdy płyta próbuje wstać) z przetwornicy PU8101 wchodzi na driver PU8102

dittos написав:PL302 = 101 Ohm

Hello!
Which coil is PL302?

dittos написав:PL502 = 47 Ohm

Please, measure the resistance to ground on this coil with and without RAM memory connected.

dittos написав:Czyżby 2 Ohmy na tym procku to za mało i to on jest problemem?

This resistance seems fine for this type of CPU.

How about the resistances to ground on coils PL1302, PL1401, PL7202?

matic написав: Which coil is PL302?

I'm sorry my mistake, its PL1302 of course

matic написав:

dittos написав:PL502 = 47 Ohm

Please, measure the resistance to ground on this coil with and without RAM memory connected.

PL502 = 47Ohm with memory connected and 230Ohm without memory

matic написав:How about the resistances to ground on coils PL1302, PL1401, PL7202?

PL1302 = 101 Ohm
PL1401 = 305 Ohm
PL7202 = 56 Ohm

Measure the voltages to ground on all coils for a short time, when the machine is turned on (power consumption is 700mA).

matic написав:Measure the voltages to ground on all coils for a short time, when the machine is turned on (power consumption is 700mA).

PL1302 = 1,35V
PL1401 = 1,01V
PL7202 = 0,93V
PL502 = 1,2V
PL8107 = 0V
PL8101, PL8306, PL8305, PL8106 = 0V
PL8301 = 1,15V
PL602 = 1,06V
PL301 = 0,2V without battery, 14,8V with battery (charging starting)
PL402 = 3,36V
PL1501, PL1504 = 0,8V
PL404= 5,1V

Can help me anyone?

Measure the following voltages to ground for a short time, when the machine is turned on (power consumption is 700mA):
- On pins 21, 23, 24, 25, 26, 27, 29, 45, 54 of chip PU8101.
- On pin 7 of chip PU8301.

Kluczowa jest obecność PLTRST .
Jeśli PLTRST=H i nie ma DDR, to płyta powinna zatrzymać się na ustalonym poborze prądu i czekać.
Jeśli go nie ma , to jest to problem power sequence.
Punktowe nagrzewanie się PCH lub CPU w większości świadczy o uszkodzeniu chipsetu.

matic написав:Measure the following voltages to ground for a short time, when the machine is turned on (power consumption is 700mA):
- On pins 21, 23, 24, 25, 26, 27, 29, 45, 54 of chip PU8101.
- On pin 7 of chip PU8301.

PU8101
pin 21 = 0,6V
pin 23 = 0,06V
pin 24 = 0,13V (sometimes 0,52V)
pin 25 = 1,05V
pin 26 = 1,05V
pin 27 = 3,3V
pin 29 = 5,1V
pin 45 = 4,7V
pin 54 = 2,45V

PU8301
pin 7 = 3,3V

dittos написав:PU8101
...
pin 45 = 4,7V

Is this measurement correct? If so, check the resistor PR8172 (100kΩ).

matic написав:

dittos написав:PU8101
...
pin 45 = 4,7V

Is this measurement correct? If so, check the resistor PR8172 (100kΩ).

Yes, measurement correct. This voltage on pin 45 is befor and after power on

Resistor PR8172 =115kΩ (measurement without desoldering)

Replace the resistor PR8172 (100kΩ).

matic написав:Replace the resistor PR8172 (100kΩ).

After replacement PRB8172 nothing changed.

I have second mainboard with another fault and measurements of the voltage on pin 45 of PU8101 and measurements of the resistance of PR8172 are similarly
I don't know what do it

The resistance to ground on pin 45 of chip PU8101 must be 100kΩ or less.

Also replace the resistor PR8169 (510kΩ) and remeasure the voltage to ground on pin 45 of chip PU8101.

matic написав:The resistance to ground on pin 45 of chip PU8101 must be 100kΩ or less.

Also replace the resistor PR8169 (510kΩ) and remeasure the voltage to ground on pin 45 of chip PU8101.

Yes, now on pin 45 resistance is 80kΩ and voltage 3,2V always.
After push power switch, not difference.

dittos написав:Yes, now on pin 45 resistance is 80kΩ and voltage 3.2V always.

That's exactly as it should be.

Was the old resistor PR8169 corroded or otherwise visibly damaged?
- If yes, carefully inspect all other small components around the chip PU8101 under the microscope.
- If not, replace the chip PU8101.

matic написав:

dittos написав:Yes, now on pin 45 resistance is 80kΩ and voltage 3.2V always.

That's exactly as it should be.

Was the old resistor PR8169 corroded or otherwise visibly damaged?
- If yes, carefully inspect all other small components around the chip PU8101 under the microscope.
- If not, replace the chip PU8101.

I replaced PU8101 and the laptop also restarts, but faster. The time between restarts has shortened.

Remeasure the voltages to ground on all coils for a short time, when the machine is turned on.

matic написав:Remeasure the voltages to ground on all coils for a short time, when the machine is turned on.

PL1302 = 1,35V
PL1401 = 1,01V
PL7202 = 0,93V
PL502 = 1,2V
PL8107 = 0V
PL8101, PL8306, PL8305, PL8106 = 0V
PL8301 = 1,05V
PL602 = 1,06V
PL301 = 0,2V without battery, 14,8V with battery (charging starting)
PL402 = 3,36V
PL1501, PL1504 = 0,8V
PL404= 5,1V

Voltages are identical as before change PU8101
I think that processor probably broken, on thermal camera the processor core shines in one corner only

dittos написав:on thermal camera the processor core shines in one corner only

That's probably because only the "+VCC_SA" power rail is present while all other power rails are missing.

Reflash the BIOS chip again with old (original) dump.
If it does not change anything, the CPU is very likely broken due to damaged driver chip PU8102.