HP Notebook 17-CN (6050A3261701-MB-A02) - No Charge, No ACDRV with Battery & Adapter

Hello

I have an HP Notebook 17-CN (6050A3261701-MB-A02) that does not charge the battery, it will power on from the battery alone, and also power on from adapter alone, but when both are connected the ACDRV for the adapter mosfets is 0v and laptop will only run from battery, despite the orange LED showing and Windows sees the battery as charging even tho no current is drawn. There does appear to be some slight damage to the battery connector to (see picture of area below)

The mosfets have measured ok all in the Mohm range
S-D = 3.8M ohm
G-D = 5.1M ohm
S-G = 4.1M ohm

S-D = 2.7M ohm
G-D = 4.9M ohm
S-G = 4M ohm

Charging IC is BQ24725A, all measurements appear to be ok, apart from the ACDRV issue. IC and adapter mosfets have been replaced and still same prblem occurs.

4 = 0v
5= 3.3v
6 = 2.6v
8= 3.3v
9= 3.3v
10 = 0.9v
11= 18.6v
12= 12.4v
13= 12.4v
14= 0v
15= 0v
16= 6v
20 = 18.8v

When i unplug the battery whilst adapter is connected, DC jack LED goes off and ACOK drops to ~200mV.

Below are some other observations i noticed.

ACOK Bat and Adapter = 3.3v
ACOK Adapter only = 3.3v

Bat & Adapter ACDRV at BQ = 0v ACDRV at MOSFET Gate = 0v
Adapter only ACDRV at BQ = 25v ACDRV at MOSFET Gate = 25v

Adapter mosfets with Bat and adapter
S= 0v D= 19v G= 0v
Adapter only S= 19v D= 19v G= 25v



Thanks

Such melted connector could mean that the metalic part inside is not providing enough contact between motherboard and battery. I would start with replacing this connector.

I see it is a standard HP one so You can take one from some HP scrapboard or You can search for new one.

You can also measure resistance of all battery poles - with battery disconected of course - to the pins on the backside of this connector. If the resistance is higher than +-0.2Ohms on any pin, then this connector needs to be replaced.

Hi

The damage to the battery connector doesnt look that serious to have damaged the pins.

There is continuity on all pins of the battery connector from the pin to the underside of the board all around 0.02ohms.

Inside this connector there is surely residue of carbon which means there are shorts between the poles. With this picture this connector surely must be replaced. I would also avoid connecting battery to it as this can lead to permanent battery failure.

tekort писал(а):Inside this connector there is surely residue of carbon which means there are shorts between the poles.

Really? none of the pins are shorting together, and there is clear continuity through the connector for each pin. I can replace it but im not sure that it is the problem.

What caused this burn?

If mosfets go to 0V when You connect AC, then there are two possibilities:
1. the burned connector has a short
2. battery is damaged and has an internal short that blocks charging circuit, otherwise You would see a nice flame

I am unsure of the history of the laptop, i recieved it in this state.

The laptop does work on the battery alone, and it works on the adapter alone, but when both adapter and battery are connected the ACDRV from BQ chip drops to 0v and the adapter side mosfets Gate do not open.

I have tried with another battery and it is the same story, there are no shorts on the board that i can see. Resistance on all pins of the battery connector do not show any shorts otherwise it wouldnt be able to power on from the battery?

You can also post measurments on this connector:
- voltage to ground with only adapter connected, no battery
- voltage to ground with battery connected, no adapter
- then with both connected

Powering always works if the battery has the charge inside. Charging on the other hand is more complicated as it uses SMBus interface with SDA signal as data, and a clock with SCL signal. If those signals are missing or wrong, the charging will not start, but the battery still can power up the motherboard.
I will still obide with replacing this connector first hand & if that changes nothing, then go further. Also, remeber to have a known working battery to test this after replacing this connector.

Battery connector Adapter only
1= 2.6v
2= 2.6v
3= 3.3v
4= 3.3v
5= ~1.5v (decreasing)
6= 3.2v
7= gnd
8= gnd

Battery connector Battery only
1= 12.3v
2= 12.3v
3= 3.1v
4= 3.1v
5= 3.2v
6= 0v
7= gnd
8= gnd

Battery connector Battery and Adapter
1= 12.3v
2= 12.3v
3= 3.2v
4= 3.2v
5= 3.2v
6= 0v
7= gnd
8= gnd

With any of the above configuratins on the BQ chip, SDA and SCL are 3.3v

I have tried with a known working battery and still same result.

Replacing battery connector made no difference.

Ok, so now we know this connector is solid and in good shape It still would be nice to know what led to this kind of failure. Post the HP PN found on sticker of the board & full model name of the device to better recognize the MB. Also post the type of KBC.

Was the board spilled?
Was there any signs of burned components when You first started working with the MB?
Was any of MOSFETs or ICs damaged previously?

As there is no documentation for this board, we need to search a similar platform to this one and then proceed further. Make good photos on both sides of the board and some better pictures of charger area with good lighting. Also post all voltages to ground of charger IC pins when adapter and battery is connected.

@tekort
Yes but unsure on the history of the laptop and what caused the problem, HP part number is M50452-601, cant find any schematics/boardview online, i thin it is same similar board to the HP 470 G8 model. Laptop full model is Notebook 17-CN0534SA.

KBC = IT8987E

No signs of liquid damage at all.

No damage to any components that i could see on initial inspection. BQ measurements are in OP.



Hi @Vogelek23

Q6012
No, i dont think there is any short there,
D-S = 150k ohm
D-G = 2.8M ohm
S-G = 2.9M ohm

Post good quality photos of both sides of whole the board as mentioned in my post #10

KenM0560 писал(а):@tekort

No signs of liquid damage at all.

There are some signs of BIOS chip replacement & some pads there were repaired. Originally on this board was Winbond W25Q64**** chip and You have ISST (?) Remove the CPU foil to make sure that the CPU was not spilled.

Laptop was recieved with the ISSI chip, and two pulled pads, they were repaired and BIOS is working as it should now, it wasnt liquid damage.