HP Laptop 25-dw2000nl Power supply

[RGSound]

Good morning,
I have a problem with my HP 25-dw2000nl laptop. Since a couple of days the battery is not charging. I've tried changing both the power supply and the battery but either way it won't charge or hold a charge.

The laptop then only turns on and works when connected to the power supply. As soon as I unplug it it has no charge and shuts down. What could be the problem, can you help me?

I'm sorry if the topic is not in the right area.

[mon2]

Hi. Are the replacement power adapter and battery known good parts and suitable for this model of laptop?

Do you have a multimeter? Soldering tools? Which logic board is onboard? Share pics of all silkscreen text of the logic board.

[RGSound]

Thank you for the answer. Yes they are both suitable for this model. I have all the tools I attach some photos if there is need for something more specific let me know.

[mon2]

Would you see any white silk screened text on the board for identification? Perhaps 'LA-****' or 'NM-****' or similar. This will assist us on perhaps finding a schematic. If not, need you to trace where the power enters the board and which mosfets are near the charging port and finally the charging IC that is driving these mosfets. Not impossible to work without a schematic but it helps.

[RGSound]

I found it, I leave photo attached. LA-H328P

[mon2]

Great. Could not find this exact board but maybe found a similar logic board from HP.

Can you confirm the topside chip markings for PUB1 = charging IC on the board?

[RGSound]

Is this one?

[mon2]

Perfect! Yes, this is the charger IC and will be very helpful to diagnose.

It is this charger IC that is detecting your power adapter and then creating a boosted voltage to enable the DCin mosfets to power the board. It is a critical part on the board.

You can download the datasheet for this part from here:

bq24735 1- to 4-Cell Li+ Battery SMBus Charge Controller for Supporting Turbo Boost Mode With N-Channel Power MOSFET Selector datasheet (Rev. B)

Use the datasheet to review the topside view and where the pin #1 is located on the chip. Pin #1 = circle on the top left of the IC -> then you will count in a COUNTER-CLOCKWISE direction (as shown in the datasheet top view).

Remove all power. No battery. Meter in resistance mode.

Measure the resistance (not diode mode) to ground of pin # 1 and then of pin # 2. Post each measurement. We are checking if the main power rail is shorted and causing the charger IC to power OFF to prevent damage.

[mon2]

My bad - unit works but does not charge. Are your meter probes sharp at the tips? We will need to check some points on the board while it is powered on.

Interested in the voltage to ground of pin # 5 - it is a corner pin. Red probe on pin #5 and black probe to ground (shield is ok). What is the voltage measurement?

[RGSound]

I will try to do this test, even I am not very experienced. As for the shield, what do you mean?