Acer Nitro5 (N20C2) doesn't charghe battery

[shybear]

hi,
I don't figure out why this laptop doesn't charge battery. At first I thought it was the original battery that showed charged at 100% didnt' work at all. So I bought a new battery that is recognized from operating system and shows its charging. orange charge LED is on but keep it under charge dosen't charge! So I downloaded board schematic (Compal LA-L191P rev. 1C) and find out that D-S of PQ 201 give 1.7 ohm no matter if battery is connected or not but gate result insulated from drain and source. So i moved away mosfet and on board short disappear but testing mosfet looks working. Anyway I had here an other Compal board with same component and I replaced it with any success. Power adapter is orginal and using a lab power supply from laptop in shut down orange charge LED is on but current rise just to 0,03 A.
Between + and GND there is just 1,5V and on pin 7-8 and GND just 3,2V. I'm sure that the new battery works properly because I tested it on an other same laptop. I attach the picture of schematic Really thanks in advance for some support.

[mon2]

Attach the power adapter. Meter in DC volts mode (30v or higher is ok).

Measure the voltage to ground on each pin on DCin mosfet PQB11.

Interested in the voltage on

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

PUB1 (charger IC):

pin 28 (Vcc)
pin 24 (REGN)
pin 6 (ACDET

[shybear]

Thanks mon2 for reply.
Laptop isnt' mine and the owner didn't sat me anything but on the internal side of back cover I noticed some trace of possibile liquid and there some little trace of liquid (maybe coffee or coke) on the right side of ram socket . (ref. Nitro5.jpg)
I still didnt' dismount mainboard thing that I finished to make right now.
There were also a great trace of oxide and PUB1 was really in bad condiction. (ref. PUB1.jpg)

I cleaned carefully all and lucky pcb stil looks in good shpe and also PUB1 looks like (ref.PUB1_OK.jpg) ok and doesn't over heat if I power board.
Cleaned it solved the weird short between drain and source of PQ 201.

As asked here's valuse you asked me for:

PQB11 (near DC power socket):

1-2-3 (source): 19,7 V
4 (gate): 25,5 V
5-6-7-8 (drain): 19.7 V

PUB1 (charger IC):

pin 28 (Vcc): 19,37 V
pin 24 (REGN): 6,0 V
pin 6 (ACDET): 2,6 V

Battery isn't still charching but as before is recognizd from Windows and looks like its charching, also orange LED is still on.
Waiting for your opinion about voltage values.

Thanks

[mon2]

The charger IC looks really bad but the cleaned up is improved. Be sure every part is clean of any corrosion. Use the TI datasheet to locate the battery charge mosfets. Then remove all power -> measure the resistance of each mosfet linked to the battery. It is possible that you have a leaky high side mosfet that is used to dial up the charge voltage for the battery unit.

The posted voltages (above) all look correct.

[mcplslg123]

Dont use such cheap quality flux. Use atleast a flux like AMTECH

[shybear]

I think the PUB1 works properly. Also mosfet PQB1 - PQB2 and PQB13 looks good - no shorts. I've a doubt that something doesn't works as expected because +17.4V_BATT_CHG is just 4,9V even if on pin 5-6-7-8 of PQB13 there are correctly 19V

[mon2]

Carefully, measure the voltage to ground on each pin on this charger IC.

Also suggest to remove all power -> no battery -> meter in resistance mode -> measure the resistance between the battery charge current leg on the charger IC. Measure directly on the charger IC. The full path resistance must be very close to the resistance in the schematic. What is the resistance in ohms of this path?

The battery is still a suspect unless you are testing this exact battery on the same logic board in another box.

[shybear]

Carefully, measure the voltage to ground on each pin on this charger IC.

Also suggest to remove all power -> no battery -> meter in resistance mode -> measure the resistance between the battery charge current leg on the charger IC. Measure directly on the charger IC. The full path resistance must be very close to the resistance in the schematic. What is the resistance in ohms of this path?

The battery is still a suspect unless you are testing this exact battery on the same logic board in another box.

If I understand well if I measure restitance between PIN 27 (PHASE LX_CHRG) and +17.4V_BATT (i.e. pin1 of PCB28) I get 30 ohm.

[mon2]

No. Remove all power. Meter in resistance mode. One meter probe on pin # 19 of PUB1. Other meter probe on pin # 20 of PUB1. What is the resistance in ohms?

We are checking the full path resistance of the current sense loop circuit used by the battery.

[mcplslg123]

PQ201 working properly? What is the voltage on battery connector pins
01.Only adapter
02.Adapter+battery

[shybear]

No. Remove all power. Meter in resistance mode. One meter probe on pin # 19 of PUB1. Other meter probe on pin # 20 of PUB1. What is the resistance in ohms?

We are checking the full path resistance of the current sense loop circuit used by the battery.

ah ok. I didn't understand exactly your first message so I detailed exactly where I made measurment. In the meanwhile following your suggestions I wanted to check better battery so I charghed it directily connecting to power supply. When I put on laptop again and started operating system battery LED was still orange but at the end of operating system turned to blue and battery level showd 100%. So I disconnevted power adapter and laptop didnt' shut off but battery level went down to 99% so I plugged again power adapter and battery LED went orange for like 1 minute and next turned blue again and battery went to 100%. I supposed that all worked fine! Next I wanted to make a double check leaving battery discharge at 91% and next I plugged again power adapter but even if system says battery charge level doesn't rise up staying at 91%.

Going to resistance values of PUB1 you asked me for are:

pin #19 - GND arounf 9 MB (rising to infinite)

pin #20 - GND 65K

[shybear]

PQ201 working properly? What is the voltage on battery connector pins
01.Only adapter
02.Adapter+battery

Testing PQ 201 works fine.

On battery connector PJP201:

without connecting battery: 4,98 V

with (charghed) battery 16,1 V

[mon2]

We still need to confirm the path resistance between pins # 19 & # 20 on the charger IC.

From post #9 - Remove all power. Meter in resistance mode. One meter probe on pin # 19 of PUB1. Other meter probe on pin # 20 of PUB1. What is the resistance in ohms?

We are checking the full path resistance of the current sense loop circuit used by the battery.

[mcplslg123]

You need to post voltage on all pins of battery connector and not the positive pinonly as asked in post#10

[shybear]

We still need to confirm the path resistance between pins # 19 & # 20 on the charger IC.

From post #9 - Remove all power. Meter in resistance mode. One meter probe on pin # 19 of PUB1. Other meter probe on pin # 20 of PUB1. What is the resistance in ohms?

We are checking the full path resistance of the current sense loop circuit used by the battery.

Ouch forgive me! I was reading your message too quick.

On PUB1:

pin #19 - pin #20 resistance (with no power) is: 20 ohm

[shybear]

You need to post voltage on all pins of battery connector and not the positive pinonly as asked in post#10

PJP201 battery connector voltage:

pin# ______no bat__ charghed bat (orange led ON)

1 - 2_____ GND____ GND

3________ 3,2 V____ 3,2 V

4 ________3,2 V____ 3,2 V

5________ 3.1 V______ 153 mV

6__________ 0 V_____ 0 V

7 - 8______ 4,9 V___ 16,2 V

[mon2]

The current sense path for the battery leg is fine.

Remove all power. Meter in diode mode. Test the dual diode @ PDB1. The diode should conduct in one direction (red on anode; black on common cathode) but should block in reverse. Test both diodes.

[shybear]

The current sense path for the battery leg is fine.

Remove all power. Meter in diode mode. Test the dual diode @ PDB1. The diode should conduct in one direction (red on anode; black on common cathode) but should block in reverse. Test both diodes.

Put black on PIN 1 and positive on PIN 2 or PIN 3 give 0,605V on reverse blocked

[mon2]

Conducts in both directions? Flux and remove this part. Test again while it is off the board. Careful to not lose this tiny part. Been there.

[shybear]

Conducts in both directions? Flux and remove this part. Test again while it is off the board. Careful to not lose this tiny part. Been there.

Yep before to remove I tested again. Now I removed PQB1 and it just give 0,6V if I put - on PIN1 and + on PIN3. Right now I put back this component and works fine., but battery still doesntì charge.