Lenovo G50-70 nie uruchamia się.

Lenovo G50-70, płyta ACLU1/ACLU2 UMA NM-A272 rev.1.0

Laptop nie uruchamia się. Po wpięciu zasilacza miga dioda ładowania baterii, po wciśnieciu power zapala się na moment dioda uruchomienia i zaraz gaśnie.

Po wpieciu zasilacza obecne jest 3.3v i 5v. Po wcisnieciu start ginie 3.3v.

Rezystancja względem masy wygląda następująco:

PL303 - 3.26kΩ
PL304 - 75.5kΩ
PL9 - 90Ω
PL307- 302Ω
PL701 - 116Ω
PL302 - 310kΩ

Po naciśnięciu start ginie 3.3v i rezystacja na PL303 spada do 24Ω.
Goła płyta pobiera 0.02A natomiast linia 3.3v po podpieciu zasilacza pobiera 0.17A i nic sie specjalnie nie grzeje (jedynie PU904 ma jakieś 30°).

Hello!

Measure the resistances to ground on pin 1 of transistors Q23, Q24.

Hi.

matic ha scritto:Measure the resistances to ground on pin 1 of transistors Q23, Q24.

Q23 - pin 1 is 62kΩ
Q24 - pin 1 is 7.6kΩ

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

Something changed now: I have opened the jumper PJ303 and PJ304 and soldered it back after some checks and now motherboard stays on when power is switched but there is no voltage except coils PL303, PL304 and PL302.

Measure the voltages to ground on pins 1, 4, 8 of transistors Q23, Q24 when the machine is turned on (power LED is turned on).

matic ha scritto:Measure the voltages to ground on pins 1, 4, 8 of transistors Q23, Q24 when the machine is turned on (power LED is turned on).

Q23
1- 0
4- 0
8- 5.1v

Q24
1- 0
4- 0
8- 3.36v

Measure the voltages to ground on pins 2, 12, 14, 18, 21, 74, 87, 93, 98, 106, 108, 109, 111, 112, 124, 128 of KBC chip, when the machine is turned off.

Measure the voltages to ground on pins 2, 11, 18, 21, 30, 72, 79, 84, 86, 87, 93, 106, 110, 123, 124, 125 of KBC chip, when the machine is turned on (power LED is turned on).

matic ha scritto:Measure the voltages to ground on pins 2, 12, 14, 18, 21, 74, 87, 93, 98, 106, 108, 109, 111, 112, 124, 128 of KBC chip, when the machine is turned off.

Measure the voltages to ground on pins 2, 11, 18, 21, 30, 72, 79, 84, 86, 87, 93, 106, 110, 123, 124, 125 of KBC chip, when the machine is turned on (power LED is turned on).

Off:
2-20
12-1,76
14-3,22
18-0
21-3,36
74-3,36
87-3,03
93-3,35
98-0
106-0
108-0
109-3,35
111-3,35
112-3,35
124-0
128-3,36

ON:
2-3,36
11-0
18-0
21-0
30-0
72-0,5
79-0
84-3,36
86-0
87-4,59
93-3,36
106-0
110-3,03
123-3,33
124-0
125-0

Lack of communication with the PCH contained in the APU.
Probable APU broken.
Attempt a reflow of the APU.

No change after reflow. The only difference is that it is starting now just after the cable is plugged in and shuts off straight away (again the 3.3v line is disappearing and resistance goes down to 20Ω).

Thanks for your help.