Hello everyone
I've bought this laptop which had got a corrupted BIOS. I've reflashed it and now it works fine. However, I've noticed it does not charge the battery: Windows says "0% plugged in, charging" but nothing happens even after many minutes. Battery utilities correctly read its data (model, charge, etc.).
I've disassembled the laptop again to look for damages in the charging circuit.
This notebook uses a BQ24725A IC charger. I've measured all the voltages out of its pins. These are my measurements (all relative to GND):
1 ACN 19,30
2 ACP 19,30
3 CMSRC 19,30
4 ACDRV 25,00
5 ACOK 3,00
6 ACDET 2,62
7 IOUT 0,00
8 SDA 3,30
9 SCL 3,30
10 ILIM 0,82
11 BATDRV 4,32
12 SRN 4,322
13 SRP 4,389
14 GND 0,00
15 LODRV 0,75*
16 REGN 6,00
17 BTST 10,20*
18 HIDRV 5,33*
19 PHASE 4,32*
20 VCC 18,80
I placed an asterisk* near some values because it is just an average voltage. Indeed, the signals associated are periodic waveforms (square wave-like). Here you can view a gallery of them (oscilloscope settings: 10V/div, 0.5µs/div): https://postimg.org/gallery/35fhvsx14/
I don't know if these signals are correct (or is it just the charger restarting itself?).
SMBus communication should be correctly working. I can see data exchange to and from the battery continously.
The voltage the battery receives from the charger is about 4.3V, and battery's nominal voltage is 15V, so it's defintely too low to charge it.
Actually, I don't even know if the battery works. As I said, I've bought this laptop as used. However, after several trials I noticed that once or twice the battery received about 16V from the charger. I don't understand what makes it work correctly in these rare cases.
Something else I noticed is that part of the battery warms up if connected for some time to the computer and some components (N-MOSFETS, inductor, the charger) warm up a little bit as well.
Anyway, so far I've replaced the BQ24725A IC, some Shottcky diodes and the two N-MOSFETS (high and low side) which have been the culprits of many notebooks' faults. The situation isn't changed at all. That is why I am kindly asking here for help. Thanks
Oh, and if you need to see the circuit, just search for ASUS UX31 schematics, the same charging circuit is implemented there as well.
I've bought this laptop which had got a corrupted BIOS. I've reflashed it and now it works fine. However, I've noticed it does not charge the battery: Windows says "0% plugged in, charging" but nothing happens even after many minutes. Battery utilities correctly read its data (model, charge, etc.).
I've disassembled the laptop again to look for damages in the charging circuit.
This notebook uses a BQ24725A IC charger. I've measured all the voltages out of its pins. These are my measurements (all relative to GND):
1 ACN 19,30
2 ACP 19,30
3 CMSRC 19,30
4 ACDRV 25,00
5 ACOK 3,00
6 ACDET 2,62
7 IOUT 0,00
8 SDA 3,30
9 SCL 3,30
10 ILIM 0,82
11 BATDRV 4,32
12 SRN 4,322
13 SRP 4,389
14 GND 0,00
15 LODRV 0,75*
16 REGN 6,00
17 BTST 10,20*
18 HIDRV 5,33*
19 PHASE 4,32*
20 VCC 18,80
I placed an asterisk* near some values because it is just an average voltage. Indeed, the signals associated are periodic waveforms (square wave-like). Here you can view a gallery of them (oscilloscope settings: 10V/div, 0.5µs/div): https://postimg.org/gallery/35fhvsx14/
I don't know if these signals are correct (or is it just the charger restarting itself?).
SMBus communication should be correctly working. I can see data exchange to and from the battery continously.
The voltage the battery receives from the charger is about 4.3V, and battery's nominal voltage is 15V, so it's defintely too low to charge it.
Actually, I don't even know if the battery works. As I said, I've bought this laptop as used. However, after several trials I noticed that once or twice the battery received about 16V from the charger. I don't understand what makes it work correctly in these rare cases.
Something else I noticed is that part of the battery warms up if connected for some time to the computer and some components (N-MOSFETS, inductor, the charger) warm up a little bit as well.
Anyway, so far I've replaced the BQ24725A IC, some Shottcky diodes and the two N-MOSFETS (high and low side) which have been the culprits of many notebooks' faults. The situation isn't changed at all. That is why I am kindly asking here for help. Thanks
Oh, and if you need to see the circuit, just search for ASUS UX31 schematics, the same charging circuit is implemented there as well.
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