• Acer Nitro 5 LA-j891P brak +VCC_CORE

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#1 Acer Nitro 5 LA-j891P brak +VCC_CORE


by Radek1990 4 March 2024, 19:06
Płyta startuje, pobiera ok 0,75A i stoi.
Próbowałem wgrywać inne biosy ale na każdym zachowuje się tak samo, brakuje napięcia na cewkach +VCC_CORE.
PL1101 - 50 OHM
PL501 - MOHM
PL301 - 25KOHM
PL1801 - 4,5 KOHM
PLV2,3,4 - 0,4OHM
PLW1,2 - 74 OHM
PLB2 - MOHM
PLM1 - 182 OHM bez pamięci
PL1001 - 14 OHM
PLH1 - 40 OHM
PLA1,2,3,4 - 15 OHM
PLG1 - 4,5 OHM
Image

Re: Acer Nitro 5 LA-j891P brak +VCC_CORE


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#2 Re: Acer Nitro 5 LA-j891P brak +VCC_CORE


by matic 6 March 2024, 09:40
Hello!

- Measure the resistance to ground on coil PLZ1.
- Measure the voltages to ground on all coils.

#3 Re: Acer Nitro 5 LA-j891P brak +VCC_CORE


by Radek1990 7 March 2024, 01:14
PLZ1 - 1,7 OHM
---------------
PL1101 - 1,06v
PL501 - 5,1v
PL301 - 3,3v
PL1801 - 1,8v
PLV2,3,4 - 0,8v
PLW1,2 - 1,3v
PLB2 - 0,2v
PLM1 - 1,2v
PL1001 - 0,94v
PLH1 - 1,04v
PLA1,2,3,4 - 0v
PLZ1,2,3,4 - 0v
PLG1 - 0v

#4 Re: Acer Nitro 5 LA-j891P brak +VCC_CORE


by matic 7 March 2024, 11:18
Measure the voltages to ground on pins 15, 16, 17, 27, 40, 41, 42, 43 of chip PUZ1.

#5 Re: Acer Nitro 5 LA-j891P brak +VCC_CORE


by Radek1990 8 March 2024, 00:38
15- 19V
16- 5,05V
17- 4,9V
27- 5,1V
40- 1,04V
41- 0,08V
42- 1,04V
43- 3,3V

#6 Re: Acer Nitro 5 LA-j891P brak +VCC_CORE


by matic 9 March 2024, 17:01
Measure the resistance to ground on pin 41 of chip PUZ1.
If the resistance is high (in kΩ range or greater), replace the chip PUZ1.

#7 Re: Acer Nitro 5 LA-j891P brak +VCC_CORE


by Radek1990 9 March 2024, 21:43
pin 41 of chip PUZ1. - 352 Ohm

#8 Re: Acer Nitro 5 LA-j891P brak +VCC_CORE


by matic 11 March 2024, 09:48
Remove the chip PUZ1 from the board and remeasure the resistance to ground on pad 41 on the place of this chip.

#9 Re: Acer Nitro 5 LA-j891P brak +VCC_CORE


by Radek1990 11 March 2024, 19:25
Po zdjęciu PUZ1 na pinie 41 mam 583 Ohm

#10 Re: Acer Nitro 5 LA-j891P brak +VCC_CORE


by matic 12 March 2024, 08:54
Perform the following measurements with the chip PUZ1 removed from the board:
- Measure the resistance to ground on pin 14 of chip UQ2.
- Set your multimeter to the diode test mode and measure the voltage drops to ground on pads 40, 41, 42 on the place of chip PUZ1.

#11 Re: Acer Nitro 5 LA-j891P brak +VCC_CORE


by Radek1990 12 March 2024, 09:31
- Measure the resistance to ground on pin 14 of chip UQ2.
Jeśli czerwony przewód daję do masy to mam 567 Ohm
Jeśli do masy dam czarny przewód, wtedy mam 287 Ohm.

PUZ1
40 - 0,272v
41 - 0,320v
42 - 0,317v

#12 Re: Acer Nitro 5 LA-j891P brak +VCC_CORE


by matic 13 March 2024, 08:57
Replace the chip PUZ1.

#13 Re: Acer Nitro 5 LA-j891P brak +VCC_CORE


by Radek1990 13 March 2024, 10:10
Mogę użyć NCP81215 lub NCP81215D zamiast NCP81215P?

#14 Re: Acer Nitro 5 LA-j891P brak +VCC_CORE


by matic 13 March 2024, 20:33
It's hard to know without a test. I recommend using the same chip as originally to avoid potential incompatibility issues.

By the way, the chip NCP81215 (or exact marking NCP81215MNTXG) is available for example at Arvika (sklep.arvika.pl).

#15 Re: Acer Nitro 5 LA-j891P brak +VCC_CORE


by Radek1990 14 March 2024, 19:47
Wstawiłem NCP81215, płyta zachowuje się tak jak przed wymianą.
Image

#16 Re: Acer Nitro 5 LA-j891P brak +VCC_CORE


by matic 15 March 2024, 08:54
Remeasure the voltages to ground from post #5.

#17 Re: Acer Nitro 5 LA-j891P brak +VCC_CORE


by Radek1990 15 March 2024, 23:16
Mam takie same wartości jak w poście #5

#18 Re: Acer Nitro 5 LA-j891P brak +VCC_CORE


by matic 19 March 2024, 09:31
Try to reflow the CPU.

#19 Re: Acer Nitro 5 LA-j891P brak +VCC_CORE


by Radek1990 20 March 2024, 00:38
Reflow nie pomógł, wciąż nie mam napięć.
Wymienić procesor czy coś jeszcze można sprawdzić ?

#20 Re: Acer Nitro 5 LA-j891P brak +VCC_CORE


by matic 20 March 2024, 10:37
I think this issue is most likely related to a damage on the CPU or the PCH chip.
Unfortunately, I don't know how to diagnose which one.

Re: Acer Nitro 5 LA-j891P brak +VCC_CORE


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