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

Remeasure the voltages on PU300.

Voltages on PU300:
Pin:
1 - 0.18V
2 - 0.18V
3 - 0.26V
4 - 0.3V
5 - 0.2V
6 - 0.06V
7 - 0.3V
8 - 0V
9 - 0.3V
10 - 0V
11 - 0V
12 - 1.5V
13,14,15,16 - 19.5V
17 - 17.5V
18 - 0V
19 - 0V
20 - 0V
21 - 0V
22 - 0V
23 - 0V
24 - 0V
25 - 0.05V
26 - 0.05V
27 to 31 - 0V
32 - 0.1V

Thanks

- Measure the resistances to ground on pins 17, 18 of chip PU300.
- Check the resistor PR309 (2Ω).
If it's fine, measure the voltages to ground on both pins of diode PD300.

Pin 18 - short to ground (on PU300 chip, after desoldering short is gone)
i found that Pin 22 is shorted to ground (without PU300 soldered) - should i try short circuit test?
PR309 - 2ohms

So the charger chip PU300 is definitely damaged and needs to be replaced.

adysowski написав:i found that Pin 22 is shorted to ground (without PU300 soldered)

Remove the protection diode PD104 from the board (if present) and remeasure the resistance to ground on pin 22 on the place of chip PU300.
If the short circuit is still present without the diode (or if the diode is factory not present), the KBC chip UE3 is also damaged - remove it from the board and check the resistance again.

Okay sorry my mistake - Pin 20 is shorted to ground instead pin 22, 22 is okay (on BDV there should be PR334, but its not present on this board)
I replaced PU300, should i check now whats happening with power adapter plugged in or better check something else before? I dont want to short out this IC because i dont have them more

adysowski написав:Pin 20 is shorted to ground instead pin 22, 22 is okay

That's fine.

adysowski написав:should i check now whats happening with power adapter plugged in or better check something else before?

Check the transistors PQ302, PQ307. If both are fine, connect the power supply and check what's going on.

Ok - i remeasured PU300, board still doesnt turn on:
1. 0.3
2. 0,2
3. 0,04
4. 0,4
5. 0,5
6. 0,3
7. 0,1
8. 0,5
9. -
10. -
11. 0,3
12. 0,5
13. 8,4
14. 19,5
15. 19,5
16. 19,5
17. 19
18. 0,2
19. 3,5
20. -
21. 0
22. 0,15
23. 0
24. 0,2
25. 0,1
26. 0,1
27. 0
28. 0,1
29. 0
30. 0
31. 0
32. 0,9

Measure the resistances to ground on pins 8, 18 of chip PU300.

Both pin 8 and 18 has 7.3KΩ resistance to ground

The charger chip PU300 is bad or badly soldered.
Check the solder joints on all pins of PU300. If they are fine, replace it.

Hi guys, new PU300 charger IC came, i replaced it, made sure every pin is soldered good and i tried to plug it in to power, it immediatly got so hot that when i tried to measure it "by hand" i burnt out my finger, what should i check next? Checked resistance at every pin of charger, seems that this short didnt kill this one.

Have you soldered the new charger chip to the correct orientation (pin 1 of the charger chip to pad 1 on the motherboard)?
If so, check the transistors PQ302, PQ304, PQ307.

Found out that PQ307 is shorted internally. Waiting for new component delivery and im going to replace it, should i check anything more when this MOSFET is desoldered? Pins under PQ307 aren't shorted. Thanks

Measure the following resistances with the transistor PQ307 removed from the board:
a) Between pin 4 and pin 5 of charger chip.
b) Between pin 4 and pin 6 of charger chip.
c) Between pin 5 and pin 6 of charger chip.
d) Between pin 7 and pin 8 of charger chip.
e) Measure the resistances to ground on pins 7, 8, 17, 18 of charger chip.

Pins of PU300 IC (Charger):
4 - 5 - 2.2Mohm
4 - 6 - 2.3MOhm
5 - 6 - 1.5MOhm
7 - 8 - 370kOhm

PU300 to ground:
GND - 7 - 37kOhm
GND - 8 - 0.7MOhm
GND - 17 - 262kOhm
GND - 18 - 120kOhm

Replace the transistor PQ307 and check what happens.

Tommorow it will be delivered to me. Should i check anything more when i solder new PQ307 transistor before plugging in power adapter?
EDIT:
Okay, i soldered it in, short is gone, what should i check? Voltages on PU300? The laptop doesnt power on still Thanks:)

Ok i discovered something new, even without PR323 top leg of PC346 is shorted to B+, is it normal?

Remeasure the voltages on PU300.
I don't know which side of PC346 you say is shorted to B+, if it is on the side connected to PR324 it is normal that between PC346 and B+ you measure 2.2 ohms, value of PR324.

Voltages on pu300
1: 0.9V
2 1.6V
3 3V
4 5V
5 0
6 0
7 0
8 5V
9 0
10 0
11 0
12 0
13 19.5V
14 19.5V
15 19.5V
16 19.5V
17 19.5V
18 5.1
19 3.3
20 0
21 0
22 0
23 0
24 0
25 1V
26 0
27 0
28 0
29 0
30 0
31 0.2V
32 0.3V

Thanks