Lenovo Ideapad 320S-15IKB LA-E541P - martwy, brak reakcji

Cześć!

Obsada:
CPU: SR343
GPU: N16V-GMR1-S-A2
KBC: NPCE388NB0DX
BIOS: WINBOND 25Q64
CHARGER: ISL88739HRZ

Laptopa otrzymałem martwego, brak reakcji na zasilanie, brak poboru prądu, nic się nie nagrzewa. Brak śladów zalania na płycie. Sprawdzane na innych pamięciach, to samo. Była zastosowana dziwna, złota pasta termoprzewodząca Accura Heat Absorber Gold - wg specyfikacji nie przewodzi ona prądu. Klucze wejściowe PQ712, PQ740 są sprawne, otrzymują napięcie ~25V na bramki i otwierają je. Brakuje na płycie wszystkich napięć, brak ładowania. Brak reakcji na włącznik. Poniżej oporności na cewkach i napięcia po podaniu zasilania.

PL601 - 32 KOHM - 20V
PL602 - 0,81 KOHM - 0V
PL603 - 67 OHM Z RAMEM; 71KOHM BEZ RAMU - 0V
PL700 - 3,56 MOHM - 0,12V
PL704 - 1,5 -1,8 MOHM - 20V
PL801- 68 OHM - 0V
PLI6 - 43 OHM - 0V
PLI3 - 19,45 OHM - 0V
PLI4 - 15,33 OHM - 0V
PL904 - 32,71 OHM - 0V
PL905 - 32,5 OHM - 0V
PL501 - 4,42 KOHM - 0V
PL502 - 31,115 KOHM - 0V

Prośba o pomoc z tym sprzętem. Dzięki!

Hello!

Measure the voltages to ground on pins 1, 5, 9, 11, 12, 15, 16 of chips PU501, PU502.

PU501
1 - 0v
5 - 20v
9 - 0V
11 - 4,03V
12 - 1,44V
15 - 0,25V
16 - 0 V

PU502
1- 1,98V
5 - 20V
9 - 0V
11 - 4,63V
12 - 0,1V
15 - 4,89V
16 - 2,75V

Does this mean that PU501 is not working properly?

Measure the resistance to ground on pin 16 of PU501, PU502.

PU502 Pin 16 to ground:
1,18 MOhm

PU501 Pin 16 to ground:
0L - open line

The chip PU501 (SY8286BRAC) seems damaged. Replace it.

After replacing PU501 (found SY8286BRAC on one of the "spares" MBs) there is some progress but still not one to brag about.

The coil PL502 gets warm and now have voltage of 1,93V. All other coils have 0V.

Also the resistance to ground on pin 16 of PU501 is now 1.61 Ohms - that could mean that the 3VL line is shortcircuited, right?

Exact.
o the test described here on pin 16of PU501:
post5699.html#p5699
Probably shorted KBC.

tekort писал(а):Also the resistance to ground on pin 16 of PU501 is now 1.61 Ohms - that could mean that the 3VL line is shortcircuited, right?

First of all open the jumper PJP502 and remeasure the resistance to ground on pin 16 of PU501.
- If the resistance will still be low the PU501 or capacitor PC509 is damaged.
- If the resistance will be high (in kΩ range or greater), the short circuit to ground is on the "+3VL" power rail. In this case perform a short circuit test as suggested on the power rail "+3VL".

With the jumper PJP502 opened the resistance goes to kOhm range (something about 39 kOhms). Should I do the test with this jumper opened or shorted?

EDIT1
It needs to be shorted of course

EDIT2
Good that I asked

tekort писал(а):Should I do the test with this jumper opened or shorted?

Perform the test with the jumper opened. For a short circuit test limit the voltage to 3V.

You should perform the test on power rail "+3VL" (output pad - system side of the jumper PJP502).

Machine is unfortunately right, the KBC gets hot and takes around 1A on 1.8V.

Is there a way to download the KBC insert if it is shorted? Probably the data is faulty anyway... This KBC is a programmable one and I have only SVOD4, so the best way would be to buy and solder a programmed one. Will let You know once I will know the owners decision.

Thank You for help!

tekort писал(а):Is there a way to download the KBC insert if it is shorted?

Unfortunately it isn't.
You can open a new thread in "ZAPYTANIA O DOKUMENTACJE/BIOS" department and ask for the KBC chip dump.

Before soldering the new chip connect the power supply to the board with the jumpers PJ502 and PJP502 opened. Make sure there is a voltage 3.3V on pin 16 of chip PU501.
If so, solder a functional KBC chip, close the jumper PJP502 and connect the power supply to the board. Than make sure there is 3.3V on the coil PL501.

With PJ502 and PJP502 opened and power supply connected to the board i have 4.00V on pin 16 of PU501, so the voltage seems too high. I cannot see a pull-down resistor on the LDO line, so i suppose that the SY8286BRAC i soldered may be broken. I have also desoldered PC509. Could it be that without PC509 this voltage is 4.00V instead of 3.3V?

No the voltage, even without the capacitor, must be 3.3v.
Are you sure you have charged tester batteries?
If they are discharged you will see incorrect measurements.

I am sure about the meter , i even used 2 different ones to measure and the voltage is 3.94-4.00V (more precise one) or 4.01 on either of them.

The SY8286BRAC I soldered has marking "AWV7BB" and the original one has marking "AWV7PD" - does it makes any difference?

tekort писал(а):With PJ502 and PJP502 opened and power supply connected to the board i have 4.00V on pin 16 of PU501

This is the reason why the KBC chip died.

tekort писал(а):The SY8286BRAC I soldered has marking "AWV7BB" and the original one has marking "AWV7PD" - does it makes any difference?

No, it doesn't. This two chips are the same.
Replace this chip again.

The owner decided to sell the working parts of the laptop and did not want to repair it further. The topic can be closed now.

Thanks for matic & Machine for Your guidance!