DELL Latitude 3579 (LA-F611P) Battery Not Charging Repair

Laptop Model – Dell Latitude 3579

Board Number- LA-F611P

Fault – Battery Not Charging

 

Repair Process :

             I checked the charging chip and found that it was ISL95522 on the motherboard and ISL9538 on the drawing. I looked at the picture carefully and saw that the two chips were drawn together.

 Now I was confused. After checking for this reason, the difference between the two chips is ACIN. The ACIN on the ISL95522 motherboard is connected to a PRB07 150K resistor to ground. There is no 19V voltage divider. There is a resistor position next to it but it is not installed. The measured ACIN is 0V.

This is the application of ISL95522 on other machines. After PQB31 is turned on, ACIN is pulled low to ground. It is normal to see ACIN 0V, but ISL9538 ACIN is high level.

ACIN is obtained by dividing 19V by connecting two resistors. Coincidentally, I happen to have a DELL G3 3579 here, which was also repaired by a customer.

 When I took it apart, it looked the same as that one except for the charging chip. This motherboard uses The one is ISL3579. I measured the ACIN to be a high level of 3.9V, and the resistor position connected to ACIN is different from that of ISL95522. 

 Now I figured it out, and I used this board to test the battery. The voltage on the charging inductor was 16.8V, which was significantly higher than the battery voltage. There was also a waveform on the oscilloscope. It seemed that the battery was OK.

The peripheral components of the charging chip were also tested and no obvious problems were found, which means that the 95522 is most likely to be broken. I sent an ISL95522 and waited for a few days.

 After receiving it, I replaced it with a test charging inductor voltage of 16.8V. The waveform is now there and it can be charged. This is the end of the repair.

 Give everyone a reference!  Some people tried to change the resistor and add a resistor, but that didn't work. Since it wasn't originally on the board, there must be a reason. I have not tested these two chips interchangeably. I think ISL95522 and ISL3579 are not universal.

 Happy Repairing !!