BQ24738 Voltage Readings

[orientalsniper]

Hello, can anyone tell me if these are correct voltage readings (with battery connected) for IC BQ24738 (BQ738) ?

19.31
19.33
19.30
25.50
3.3

2.6
0.3
3.2
3.2
0.7

16.73
16.75
16.78
0
0.48

6.05
22.24
21.46
16.88
18.86

Problem with motherboard (LA-A993P) is it's not charging when powered on, can only charge battery if it's powered off. Already replaced IC, flashed bios and reprogrammed KBC.

[caspian]

Re: BQ24738 Voltage Readings

pin15 and pin18 does not seem OK. you should measure BQ24738 both when the laptop is powered on and powered off. upload the mainboard's schematics file if you have it.

[orientalsniper]

Re: BQ24738 Voltage Readings

Powered on, but not charging:

15.56
15.52
0.2
0.2
3.3

2.6
0
3.2
3.2
0.7

21.6
15.23
15.22
0
0

6.05
14.97
15.20
15.20
19.31

There's no schematic for this motherboard, but I extracted a page from a different motherboard with same charging IC.

[caspian]

Re: BQ24738 Voltage Readings

I think the measurements in Post3 are done when the AC adapter was disconnected from the laptop. If so, repeat it with the AC adapter connected. If the AC adapter is disconnected, you cannot find a clue to solve the problem.

[orientalsniper]

Re: BQ24738 Voltage Readings

Nooo, adapter was plugged!

[laztop]

Re: BQ24738 Voltage Readings

MOSFET BATT short

[caspian]

Re: BQ24738 Voltage Readings

that may be right. when the AC adapter and the battery are removed, check the Mosfets connected to BQ24738 for being shorted.

[ablbilgi]

Re: BQ24738 Voltage Readings

laztop yes gpu mosfet short for me. thanks

[jasko_jacker]

Re: BQ24738 Voltage Readings

you can use the datasheet of the bq24735 is similar.