ACER Aspire 5 A515 - nie uruchamia się

Witam.
Płyta LA-K091P. Nie uruchamia się tj. nie są otwierane wejściowe MOSFETY (PQB3 i PGB4).
Na płycie nie zauważyłem żadnych zwarć więc testowo zmostkowałem PQB3 i PGB4 i okazało się, że płyta reaguje na przycisk włączenia, jest obraz, można ją wyłączyć z przycisku.
PQB3, PQB4 i PUB1 wydawały się w porządku, ale profilaktycznie je wymieniłem, ale sytuacja jest identyczna. Tranzystor PQB2 wydaje się w porządku jak i PQB5 i PQB6.
Napięcia na PUB1 (BQ24800, pomiary z USUNIĘTYM mostkiem PQB3/PQB4):
- p. 5 : 3,3V (ACOK),
- p. 6: 2,6V (ACDET),
- p. 10: 0V (/PROCHOT),
- p. 24: 6V (REGN).
Proszę o pomoc w namierzeniu problemu.

Hello!

Measure the voltages to ground on all pins of battery connector with the power supply + battery connected.

Voltages on PJP201 (battery + power supply):
- p. 1-5: 0V,
- p. 6: 2,5V (with RTC battery connected: 0V),
- p. 7/8: 0V.

Resistance to ground on PJP201:
- p. 3: 10kΩ,
- p. 4: 10kΩ,
- p. 5: 20kΩ,
- p. 7/8: >2MΩ.


I noticed the charger tries to open the main MOSFETs, there are three attempts which last about 0,5 sek.
In addition I provide the resistance and voltages on charger (PUB1 BQ24800):
PUB1:
1. 500kΩ,
2. 5MΩ,
3. 3,8MΩ,
4. 3,8MΩ,
5. 11k,/3,3V
6. 63k,/2,6V
7. 11,5kΩ,
8. 193kΩ,
9. x,
10.1kΩ,
11.52kΩ,
12.52kΩ,
13.gnd,
14.x,
15.25kΩ,
16.x,
17.7MΩ,
18.>50MΩ
19.6MΩ,
20.6MΩ,
21.65kΩ,
22.gnd,
23.194kΩ,
24.21k,/6V,
25.18M,/5,7V,
26.6MΩ,
27.6MΩ,
28.5MΩ/19V.

Bridge pin 6 of the battery connector to ground and remeasure the voltage to ground on pin 8 of the battery connector with the power supply + battery connected.

When I short pin 6 to ground nothing happens (no changes, no voltages), pins 7/8=0V.
This is the same situation as in this case:

p. 6: 2,5V (with RTC battery connected: 0V)

so PQ201 works fine.
I have completely no idea what is wrong. The mainboard works when I short PQB3 & PGB4.
I forgot to provide voltages on PQB3 & PGB4:
PGB3 (no shorts to ground and between pins):
- p. 1-3: 0V,
- p. 4: 0V,
- p .5: 19V.
PGB4 (no shorts to ground and between pins):
- p. 1-5: 0V.

After short input MOSFETs (only MB with RAM, no HDD and no LCD):
- the current is 19,9mA (supply voltage 19,0V),
- voltage on PRB3 between pins 1/2-3/4 0,19mV.
After presing power button:
- the current is 940mA,
- voltage on PRB3 9,4mV.

Measure the resistances between listed pins:
a) Between pin 1 and pin 2 of charger chip PUB1.
b) Between pin 17 and pin 27 of charger chip PUB1.
c) Between pin 19 and pin 20 of charger chip PUB1.
d) Between pin 19 and pin 27 of charger chip PUB1.
e) Between pin 1 of charger chip PUB1 and pin 5 of transistor PQB4.
f) Between pin 3 of charger chip PUB1 and pin 1 of transistor PQB3.
g) Between pin 4 of charger chip PUB1 and pin 4 of transistor PQB3.
h) Between pin 18 of charger chip PUB1 and pin 4 of transistor PQB2.

Measurments (the resistance of the meter's measuring probes is about 0.1Ω when I short them):
p. 1-2: 2,5Ω (Is it not to much?),
p.17-27: 10Ω,
p.19-20: 20Ω,
p.19-27: 10Ω,

p.1-5: 1,2Ω (PUB1-PQB4; Is it not to much?),
p.3-1: 4,01kΩ (PUB1-PQB3),
p.4-4:4,02kΩ (PUB1-PQB3),
p.18-4:4,02Ωl (PUB1-PQB2).

Post a clear picture of the charger chip area of the board with nearby surroundings.

And from the other side

What with those resistances values, are those right:

p. 1-2: 2,5Ω (PUB1),
p.1-5: 1,2Ω (PUB1-PQB4)

BQ wydaje się "wisieć w powietrzu"[quote="luielektr"]p. 1-2: 2,5Ω (PUB1),

Nie, wszystko jest dobrze przylutowanie. Po za tym przed wymianą BQ usterka była identyczna.

[.quote="luielektr"]p. 1-2: 2,5Ω (PUB1),

Nie rozumiem.
Aby nie było niedomówień zrobiłem precyzyjniejsze zdjęcia i przelutowałem układ jeszcze raz, aby nie było widać śladów po pomiarach.

Measure the resistances between listed pins:
- Between pin 1 of charger chip PUB1 and both pins of resistor PRB3.
- Between pin 2 of charger chip PUB1 and both pins of resistor PRB3.

PUB1 > PRB3
p. 1 > p. 3/4 : 1,2Ω,
p. 1 > p. 1/2: 1,2Ω,
P. 2 > p. 1/2: 1,2Ω,
p. 2 > p. 3/4: 1,3Ω.

I just replaced the resistor but it didn't change anything.

Measure the resistance between pin 1 of transistor PQB2 and pin 1 of transistor PQB5.

PQB2 > PGB5
p . 1/3 > p. 1/3: 0Ω

These low resistance values are probably the resistances of the copper paths on the PCB itself, since the copper traces on pins 1, 2 of PUB1 are quite thin.

luielektr napisał(a):Voltages on PJP201 (battery + power supply):
- p. 1-5: 0V,
- p. 6: 2,5V (with RTC battery connected: 0V),
- p. 7/8: 0V.

With these measurements the battery is damaged and needs to be replaced. Some boards simply does not work without a functional battery connected, which I think is the cause here. Test the board with a functional battery.

Replacing the battery doesn't change anything.
This is the new one so there is no voltages on JP201 and the MB didn't even activate it.

This is photo of voltages on 4 p. of PQB3, PGB4 and p. 1-3 PGB3 (the voltages are the same). The transistor PQB4 isn't being opened.


Ps.
I'm sorry for photo but my oscilloscope doesn't recognise any external devices, I don't know what happened to it and I can't find drivers for Win10.

Po co jest tranzystor PQB1? Czy nie zabezpiecza on czasem przed zbyt wysokim napięciem zasilania i powoduje on zatkanie tranzystorów wejściowych?