Lenovo B51-80 LA-D101P REV 1.0 BIWB6/B7/E7/E8 nie uruchamia się.

Witajcie,

Obecnie mam na stole jak w temacie Lenovo B51-80

KBC NUVOTON NPCE388NA1DX
BIOS MXIC 25l6473F

Laptop nie uruchamia się, nie ładuję baterii, nie reaguję na włącznik.

Nie posiada śladów zalania ani ingerencji innych użytkowników.
Wg klienta, podczas pracy sam zgasł i zero reakcji.

Pobór płyty 0,003A na zmianę z 0,000A

Brak napięć na cewkach.
Rezystancja względem masy:

PL302 0,02 ohm
PL902 40 ohm
PL802 65 ohm
PL16 18 ohm
PLI3 8 ohm
PL502 295 ohm
PLI4 8 ohm
PL402 5k ohm
PL404 38k ohm

8 n. układ SPI 5,8k ohm
Bateria CMOS 3,1V
Bezpieczniki sprawne.

Na n.4-8 PQ301 mam napięcię 19,45V
Na n.1-4 napięcie pływa od 0,06V - 0,13V

Nie mam pełnego schematu do tej płyty, ewidentnie jest zwarcie jednak nie mogę zlokalizować dokładnie gdzie.

Jakich pomiarów dokonać jeszcze?

Z góry dziękuję za wszystkie rady

LukaszBsKrakow написав:PL302 0,02 ohm

Hello!
Did you measure this resistance with the main battery disconnected from the board?
If so, that's a short circuit to ground. Remove this coil from the board and check on which side of the coil is low resistance to ground.

Yes, measurement made with power off. I dismantled the coil, it turned out that there is a short circuit on the motherboard side. The PQ306 mosfet was short-circuited, after replacement I additionally noticed a cracked capacitor under the microscope, I replaced it, there is no short circuit anywhere. However, the board is still dead, consumption 0.000A

Measure the voltages to ground on coils PL402, PL404.

PL402 0V
PL404 0V

The board is still dead, the only voltages I have are:

BQ24780:

N.1 2.3-2.6v
N.2 2.3-2.6V
N.3 0V
N.4 0-0.12V
N.5 0V
N.6 2.6V
N.7 0V
N.8 0V
N.9 0V
N.10 0V
N.11 0V
N.12 0V
N.13 0.2V
N.14 0.4V
N.15 0V
N.16 0.1V
N.17 0.22V
N.18 0.22V
N.19 0.22V
N.20 0.22V
N.21 0V
N.24 6V
N.25 5.8V
N.26 0.22V
N.27 0.22V
N.28 19.2V
...
and the voltage is on the PQ301 drain 19.5V.

The rest of the board no voltage.

Please, post a clear picture of marked area of the board (with the protection foil removed of course).

- Measure the resistance to ground on any pin of resistor PR302.
- Measure the voltages to ground on pins 1, 4, 8 of transistors PQ301, PQ303.

I have two chargers for this laptop.
The customer provided a replacement that if I plug it in I have no voltages.
I have an original charger for Lenovo and if I connect it, the voltages are:
PR302 is 20.3V
PQ301 n.1 20.3V n.4 26.2V n.8 20.3V
PQ303 n.1 20.3V n.4 26.2V n.8 20.3V

In addition, I get very hot with PU401 (I replaced it with a new one, nothing has changed)

Measure the resistance to ground on pin 5 of chip PU401.
Chip PU401 pin count (top view):


If the resistance is low (in Ω range), perform a short circuit test described here on pin 5 of PU401. For a short circuit test limit the voltage to 3V.

The KBC chip is very likely damaged.

The resistance to ground on pin 5 is 1.5 ohms

The short-circuit test showed heating of the KBC system
At 1.5V, the draw is almost 1A.

Is this chip programmable? (NUVOTON NPCE388NA1DX)
Can I buy a new empty one and it will program itself?

Edit:

one capacitor marked in the picture needs to be replaced, what parameters should it have?

LukaszBsKrakow написав:Is this chip programmable? (NUVOTON NPCE388NA1DX)

Yes, this KBC chip requires programming.

LukaszBsKrakow написав:Can I buy a new empty one and it will program itself?

No, this chip does not support auto-programming. It needs to be programmed manually.
If you don't have a KBC programmer, you can buy a pre-programmed KBC chip for your board (ask at Kocham Basie).

LukaszBsKrakow написав:one capacitor marked in the picture needs to be replaced, what parameters should it have?
[ Obrazek ]

It's 4.7µF/6.3V, package 0603.

That missing capacitor could be 4.7uf/ 10V? That's the one I have on hand.

When disassembling the KBC, I damaged one pin No. 64, is it responsible for something important?

I don't have a datasheet for this chip.

LukaszBsKrakow написав:That missing capacitor could be 4.7uf/ 10V?

Yes, it could.

LukaszBsKrakow написав:When disassembling the KBC, I damaged one pin No. 64, is it responsible for something important?

This pin is not connected, so you can leave as it is.

I installed the KBC system programmed in the store KochamBasie.pl

I reprogrammed the BIOS with a batch from the forum, supplemented the missing capacitor and the board started.

All tests passed successfully, the laptop is returned to the owner.

Thank you for your help @matic

Temat zamykam.