Charging Issue on Dell G3 3579 (LA-F611P)

[CIT]

Hi guys,

I am working on a Dell G3 3579, with motherboard LA-F611P that is not charging.

Unit was dead with blown PU01 and I replaced PU01 along with PUB02 to get the unit going. After testing I found the unit is not charging.

I have seen this on the Dell G3 3579 on about 5 different units, but I have never been able to fix it

So I can see in the bios its not a charger detection issue, as it is detecting my 130w charger fine, but even when plugged in the battery will show its discharging. Unit works fine from battery and from charger. I have already replaced PQB06, same problem. Any advice on where I need to start testing for problems?

I have searched the forum for a similar issue, but was unsuccessful in finding anything. I have checked online as well with no luck. Also if I am not following the rules, please let me know as I am still new on this forum

I have attached the schematic and boardview file.

[Mod. Edit-Vesko356] Schematic ---> https://www.badcaps.net/forum/showth...297#post937297
Boardview ---> https://www.badcaps.net/forum/showth...87#post1234087

[Vesko356]

Re: Charging Issue on Dell G3 3579 (LA-F611P)

I have attached the schematic and boardview file.

Do not attach laptop schematic and/or BV in this section please!

Schematic Requests ONLY!
https://www.badcaps.net/forum/forumdisplay.php?f=41

Reminder: rules and organization of this section
https://www.badcaps.net/forum/showthread.php?t=117483

If you request/offer BIOS/schematics/boardviews, please post in the appropriate subsection, and you can link to it in the troubleshooting topic.

.

[rookieme]

Re: Charging Issue on Dell G3 3579 (LA-F611P)

You can check the dc in mosfets for shorts - PQ7,PQ3, PQ8 & PQ4.
Does this model has docking port?

[CIT]

Re: Charging Issue on Dell G3 3579 (LA-F611P)

Hi Vesko356, Thanks for the assistance.

Hi Rookieme, I have checked those mosfets for shorts - all tested fine. This model does not have a docking port no.

[rookieme]

Re: Charging Issue on Dell G3 3579 (LA-F611P)

do also check PRB02, PRB03, PRB32 & PRB36 for the correct values

[mcplslg123]

Re: Charging Issue on Dell G3 3579 (LA-F611P)

Measurement of charging IC's pin voltage may help.

[CIT]

Re: Charging Issue on Dell G3 3579 (LA-F611P)

Hi guys, sorry for only replying now, have been busy.

I tested PRB02, PRB03, PRB32 and PRB36 and found this:

PRB02: 0 ohm
PRB03: 2.2 ohm
PRB32: 2.2 ohm
PRB36: 0 ohm

I then replaced PRB02 with a 2.2 ohm resistor as per the schematic, I hoped it would solve the problem - but unit is still discharging even when plugged in.

Here is the measurements of PUB01 in voltage with charger plugged in:

1. 0
2. 0
3. 0
4. 5
5. 0,6
6. -0,2
7. 4,5
8. 5,3
9. 0
10. 0
11. 0
12. 5
13. 1
14. 19
15. 19
16. 2,2
17. 18,8
18. 5
19. 0
20. 1,6
21. 3,3
22. 3,3
23. 0
24. 3,3
25. 3,3
26. 1,7
27. 0
28. 0
29. 0
30. 0
31. 0
32. 0

Any ideas? xD

[mon2]

Re: Charging Issue on Dell G3 3579 (LA-F611P)

Is the battery attached in the above measurements?

[CIT]

Re: Charging Issue on Dell G3 3579 (LA-F611P)

No battery is unplugged.

[mcplslg123]

Re: Charging Issue on Dell G3 3579 (LA-F611P)

Pin19 voltage is wrong. Sure about the measurement. Suggest to re-check as pin16 is showing some voltage.

To me, pin16 should be 3.4V.PRB05/07 populated or not?

[CIT]

Re: Charging Issue on Dell G3 3579 (LA-F611P)

So I checked pin19 voltage again - still 0 volts even with battery plugged in.

Pin 16 also still showing 2.2 volts, PRB07 is populated and tested 149ohm.

[mcplslg123]

Re: Charging Issue on Dell G3 3579 (LA-F611P)

The values are given in schematic for PRB05/07. Better check them out of circuit. Be careful not to loose them. PRB05,pin1 voltage?

[CIT]

Re: Charging Issue on Dell G3 3579 (LA-F611P)

Value for PRB07 on schematic is 100k ohm, tested it out of circuit and still got 149k ohm. There is no resistor on PRB05, but pin 1 tested 20v and pin 2 tested 0v

[Sephir0th]

Re: Charging Issue on Dell G3 3579 (LA-F611P)

The schematics specifies two different charging Controller with different circuit designs depending on the actual charging controller. Probably the ISL95522 acts as Hybrid Charger (classic design) while the ISL9538H acts as Buck-Boost Converter (NVDC).

So it is important to know which charging controller is used here for further troubleshooting.

[CIT]

Re: Charging Issue on Dell G3 3579 (LA-F611P)

Hi Sephir0th, thanks for asking. The charging IC used on this board is the ISL95522

[Sephir0th]

Re: Charging Issue on Dell G3 3579 (LA-F611P)

So what do you think, how possible is it that SMDs were mixed or got lost through the soldering process of PUB01, like PRB07 with wrong value and PRB05 missing for example?

Any pictures of your work available?

[CIT]

Re: Charging Issue on Dell G3 3579 (LA-F611P)

I don't think any SMDs were mixed, my soldering skills is fairly good. I also found it strange that PRB07 tested wrong and that PRB05 was missing. I am not so good with understanding schematics yet tho, so at this point I am assuming its some configuration thing with the board model?

Here is a photo of ISL95522 (PUB01)

[mcplslg123]

Re: Charging Issue on Dell G3 3579 (LA-F611P)

In my limited knowledge, PRB07 and PRB05 -both should be there as 95222 controller is used. You have measured PRB07 at 149 Ohms at post#11 which now stands changed at 149K Ohms.

[CIT]

Re: Charging Issue on Dell G3 3579 (LA-F611P)

My apologies, that is a typo. PRB07 tested 149k ohm on and off the board.

I had a look at the schematic again now and I can see according to the schematic PRB07 should be 150k ohm on the ISL95522. The schematic also only shows PRB05 on ISL9538 and there is no indication that PRB05 is populated on ISL95522.

Here is a snip of schematic, I marked my findings in red:

[mcplslg123]

Re: Charging Issue on Dell G3 3579 (LA-F611P)

Yes,only PRB07 is populated for 95522 series.