HP laptop does not charge the battery, the light turns amber and then changes to white.

[stevenallauca]

Hello everyone. I have a problem with an HP laptop, when connecting the charger the amber light comes on for 6 seconds, changes to white and does not charge, I have checked all the components with the multimeter and the values seem correct, I was guided by the diagram, I do not know if it is a problem with the BQ24728H charge controller, investigating it seems that the voltages given by the charge controller are correct, I made the measurements connected to the power source and without the battery:
- ACN (BQACN) 19.6v
- ACP (BQACP) 19.6v
- CMSRC (BQCMSRC) 19.6v
- ACDRV (BQACDRV) 26v
- ACPRES (ACIN) 3v
- ACDET 3v
- IOUT (BQIOUT) 0v
- SDA (BQDATA) 3.6v
- SCL (BQCLK) 3.6v
- ILIM 1v
- BATDRV (BQBATDRV) 3v
- SRN (BQSRN) 3v
- SRP (BQSRP) 3v
- GND 0v
- LODRV (BQLODRV) 0v
- REGN (REGN6V) 6v
- BTST 6v
- HIDRV (BQHIDRV) 3v
- PHASE (BQPHASE) 3v
- VCC (BQVCC) 19.6v

The battery is healthy, I even tried with a new battery.
If someone can help me by telling me which are the important components for charging and I can check them again, if possible to know the voltage that must cross in a healthy charging system without problems. Attached schematic is page 27.

https://www.badcaps.net/forum/troubl...atic-boardview

[mon2]

Review the sticky above by piernov on charger circuits.

Each mosfet in the power path is a suspect. The battery srn/srp should not be at 3v. Something is wrong here. Too many 3v.

Remove all power. Meter in resistance mode. Test the resistance across each mosfet:

source (1-2-3) & drain (5-6-7-8)
source (1-2-3) & gate (4)
gate (4) & drain (5-6-7-8)

Post each measurement. Test the usual dc-in mosfets and also the battery charger mosfets.

[stevenallauca]

Hi, thank you very much for your reply, the error was pq13, I replaced it and now it charges.
But now I have the beep problem, it gives me 2 short beeps in 5 series, can you tell me what is the cause?
I did some research but I can't find any information.
Thank you for your help.

[mon2]

May be defective ram.

https://h30434.www3.hp.com/t5/Notebo...0the%20modules.

[stevenallauca]

Hello, I have already changed the RAM but the problem continues, it does not give an image to the screen.
The sound is 2 short beeps (sb) with 3 seconds, it does it like this:
2 (sb) - 3 sec - 2 (sb) - 3 sec - 2 (sb) - 3 sec - 2 (sb) - 3 sec - 2 (sb)
After this it does not beep anymore. The Caps Lock light stays on with 2 short blinks every 3 seconds, it does this indefinitely, the fan also stays on only until I remove the power from the power supply.
I tested what happens if I turn it on without RAM, the beep is 3 short times.
I also tested putting in a new CR2032 battery.
I don't know if it has anything to do with changing the mosfet, but I doubt it. The change I made was from a 6414A to a 6428. I couldn't find the 6414A, but I investigated the 6428 and it could be adapted to the 6414A work system. I changed it and it works without any problem regarding charging.

[mcplslg123]

Give us the voltage on all coils after pressing power switch. There may be a missing rail.
Observe the mb under microscope/magnifier for corrossion etc.