Dell XPS 13 9370 CAZ60 LA-E671P zalany, brak ładowania

adysowski wrote:What can be the issue?

Most likely damaged transistor PQ155, because you have exactly the same voltages on all its pins. Check it out of the board.

adysowski wrote:What voltage should be on pin 4 of PQ155?

Around 2V when the signals "VBUS3_ECOK" and "AC3_DISC#" are at high state.

What voltage should be on pin 4 of PQ155?

Based on the value of the resistors about 2V.
Measure the voltages on all pins of PQ157.

matic wrote:Most likely damaged transistor PQ155, because you have exactly the same voltages on all its pins. Check it out of the board.

When PQ155 is desoldered out of the board on pin 4 there is still 19.5V

PQ157:
pin 1 19V
pin 2 0V
pin 3 0V (GND)

After desoldering resistor PR261 (resistor alone has 500k Ohms) there is 1.9V for a little moment (like a second or something)

You are missing the VBUS3_ECOK signal on the gate of PQ157 coming from the KBC.
Are you using the original power supply?

adysowski wrote:When PQ155 is desoldered out of the board on pin 4 there is still 19.5V

Yes, because the PQ157 is not open, but you have exactly the same voltages on pins 1 and 8 of this transistor, which should not be.
Because there is a forward-biased body diode inside the transistor and additional external diode the voltages on pin 1 and pin 8 should differ for ~0.2V at least. So the transistor PQ155 or diode PD110 must be damaged based on your measurements. Please, check them.

Okay guys - diode PD110 seems to be okay - in diode mode i get 0.494V measurement (voltage drop diode), reversed polarity I get OL. PQ155 when desoldered doesnt have any shorts (pin 1-3 bridged, pin 4, pin 5-8 bridged). I resoldered PU300 IC once again (:D) and found that PU101 is BURNT! I have looked deeply into schematics - it seems that it is RT9069-33GB, can i replace it with some other regulators? I have some boards for parts - 2x LA-C551P, LA7912-P, maybe I can find some similar IC to PU101? I have schematics to them I can upload them Thanks for helping

Machine - these measurements were taken at original Apple PD 100W power supply USB-C.

PU101 when desoldered looks like this:
pin 1 - 19.8V
pin 2 - 0V (GND)
pin 3 - 0V
pin 4 - 9.7V
pin 5 - 0.04V

adysowski wrote:I have some boards for parts - 2x LA-C551P, LA7912-P, maybe I can find some similar IC to PU101?

Unfortunately there is no a suitable chip on any of these boards.
This chip is available on Allegro (item number: 13775539492).

Measure the resistance to ground on pad 5 on the place of chip PU101.

Okay. I ordered new PU101 IC. Measurement - GND to Pin 5 of PU101 (desoldered) - 2.65MΩ. Thanks for help, do I need to check anything more before PU101 IC arrive to me?

The resistance seems fine.

Also measure the resistance to ground on pin 5 of chip PU301 (without removing the chip). If the resistance is also high (in kΩ range or greater), solder the new chip PU101 and test the board.

Ok - finally PU101 came from China After soldering it laptop is completely dead. I measured PQ155 once again - I still have 19V on pin 4 of PQ155. I dont know what to measure next. I guess this transistor is dead, but after desoldering it there is still 19V on this pin.

Measure the voltages to ground on all pins of chip PU101.

PU101:
pin 1: 19.5V
pin 2: 0V
pin 3: 0V
pin 4: 9.7V
pin 5: 3.1V

Is the RTC battery charged?
If download the bill and check if you have a voltage on the gate of PQ157.

adysowski wrote:PU101:
pin 5: 3.1V

It should be 3.3V.
Is this measurement correct?

- Measure the voltages to ground on all pins of transistor PQ123.
- Measure the voltages to ground on all pins of chip PU301.
Transistor PQ123 pin count:

This measurement was not correct - there is 3.31V :

PQ123:
pin 1: 3.31V
pin 2: 0.58V
pin 3: 3.31V

PU301:
pin 1: 3.31V
pin 2: 0.04V
pin 3: 0V
pin 4: 0V
pin 5: 3.31V

Also, I desoldered PR261 - 500kOhm, MOSFET PQ155 is getting 0.3V on Gate and is opening, because PQ153 gets 1.8V on gate and is getting 20V. I dont know what to do next - RTC Battery is disconnected

Please, solder the resistor PR261 back to its place and measure the voltages to ground on coils PL301, PL302, PL501, PL504.

Reactivate the RTC battery operation.

PL301:
0V
PL302:
19.5V
PL501:
0.58V (!)
PL504:
0V

What do u mean by reactivating RTC Battery operation? U mean plug in battery? (its 3.1V, measured )

Measure the voltages to ground on pins 1, 4, 8, 12, 14, 15, 16, 17, 18, 19, 24, 25 of charger chip PU300.

PU300:
Pin 1: 8.5V
Pin 2: 8.11V
Pin 4: 5.25V
Pin 8: 5.20V
Pin 12: 5.35V
Pin 14: 19.5V
Pin 15: 19.5V
Pin 16: 19.5V
Pin 17: 19.5V
Pin 18: 5.22V
Pin 19: 3.66V
Pin 24: 0V
Pin 25: 0V
Thanks