DELL Latitude 3510, No power

[7ak7]

Hello

Dell Latitude 3510
MB: 19746-1 MOCKINGBIRD-L CML UMA 6L

The pc has no 20V_DCBATOUT. Then i found, that capacitor PC4416 was shorted to ground and PU4401 pin15 also was shorted to ground. Replaced PC4416 and PU4401. Now the 20V_DCBATOUT voltage is 19.1V
The computer still won't turn on, then I found that voltage 19V_DCBATOUT is pulsing from 3 to 3.1

Also found that charger PU4401 pin24 ACOK is 0V

PU4401 pinout voltages:
1. 3.1 (pulsing from 3 to 3.1)
2. 3.1 (pulsing from 3 to 3.1)
3. 3.1 (pulsing from 3 to 3.1)
4. 4.6
5. 0
6. 0
7. 0
8. 5
9. 0
10. 0
11. 0
12. 4.6
13. 18.4
14. 18.6
15. 19
16. 19.1
17. 18.9
18. 4.9
19. 3.7
20. 0
21. 0
22. 0
23. 0
24. 0
25. 0
26. 0
27. 0
28. 0
29. 0
30. 0
31. 3.1 (pulsing from 3 to 3.1)
32. 0.08

I cant figure out why ACOK is 0v

[mon2]

Check again the voltage again to ground on pin 14 and then pin 15 of the charger IC @ PU4401. That is a large voltage drop across these 2 current sense pins.

[7ak7]

Recheck the voltages
pin14 - 18.6v
pin15 - 19.08v

[mon2]

Too large of a voltage drop. Remove all power. Meter in resistance mode. Measure the resistance between pins 14 and 15 directly on the charger ic. Again, no power to the board. Only power to the people.

[7ak7]

Replaced PR4422 and PR4423, and pc starts normally.