Acer Nitro 5 LA-H501P Not Charging, Not Powering On

[Growtopia Jaw]

I have an Acer Nitro 5 AN515-54 no charging indicator and not powering on via AC. Battery is totally dead (0V) and I'm in the process of getting another battery that at least has some charge left in it.

I have no idea where to start so without plugging in battery and plugging in AC, I measured main voltage rails with my analog multimeter. i've also attached boardview and schematics for this motherboard.




[Mod. Edit]
Schematic and boardview:
https://www.badcaps.net/forum/troubl...11#post1492111

https://www.badcaps.net/forum/troubl...25#post1531325

Reminder: rules and organization of this section
https://www.badcaps.net/forum/troubl...f-this-section

If you request/offer BIOS/schematics/boardviews, please post in the appropriate subsection, and you can link to it in the troubleshooting topic.

[Stevedb]

You need the measurements on the charging ic

[Growtopia Jaw]

You need the measurements on the charging ic

I'm not really sure which component exactly is the charging IC. Could you help me out by pointing out the charging IC. Should I take measurements in volts, amps, resistance etc.?

[mon2]

Search for PUB1 in the PDF schematic = ISL88739AHRZ. This is the charger IC.

[Growtopia Jaw]

Which pins exactly should I measure?

Edit: In the meantime, I'm measuring all the pins' voltage just in case

[mon2]

Pin 30 is a good voltage to enable the dcin mosfets at pqb11 and pqb12.

carefully measure the voltage to ground of each pin on pqb11. Then repeat for pqb12. Post each measurement.

output at pqb12 should power the board.

[Growtopia Jaw]

Here are the measurements as requested

[Stevedb]

Looks ok so you have 19v on current sensor now we need a hd picture with all voltages on coils and resistance of the coils to ground . Resistance measured without any power and on 200ohmd or 2kohms mode or automatic but says it Kohm or Mohm.

[Growtopia Jaw]

hd picture with all voltages on coils

Could you point out where exactly could I find said coils in the schematics/ boardview? Thanks.

Edit: So basically coils are just inductors right?

[Growtopia Jaw]

I've measured resistance and voltage of the inductors and found out that almost all are 0 ohms (when NOT connected to AC) and 0V (when connected to AC) other than the PL101,102 and 103 which are getting 19V

[Growtopia Jaw]

I've also noticed that this metal bracket for the NVME slot getting quite hot for no logical reason whenever the AC adapter is connected.

Edit: I've also just noticed that PUB1 (ISL88739AHRZ) gets very hot and is burning to the touch. Could this be the issue all the other inductors aren't getting power?

[Stevedb]

Big grey coils ( squares)

[Growtopia Jaw]

Big grey coils ( squares)

I measured it with AC plugged in and found out they are all 0V. I l also measured without AC, in resistance mode and they are all 0 ohms.

PL101, PL102 and PL103 is 19V when AC is plugged in.

[Growtopia Jaw]

I've replaced ISL88739AHRZ and plugged in AC. The mosfet is no longer burning hot and is in normal temperature. But all coils are still 0V when AC is plugged in. Charger receives 19V to PL101, PL102 and PL103.

In resistance mode (not connected to AC), coils are all 0 ohms with or without ISL88739AHRZ soldered.

I no longer have any idea what to do next. Does anyone have an idea?

[mon2]

Confirm the voltage on the 2*dcin mosfets at pqb11 and pqb12.

measure:

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

for each of these mosfets. Post each measurement.

[Growtopia Jaw]

I've remeasured and these are the values

[Growtopia Jaw]

Is it safe to say that PQB11 is bad?

[mon2]

No, not yet. We know that the adapter voltage is reaching the first mosfet from the 19v measurement. The datasheet for this part identifies the part to be N-channel type. So the gate voltage must be higher than the voltage being passed between source and drain to enable. This gate voltage should be ~25 volts to fully enable these 2 dcin mosfets. Yet the gate voltage is 0 volts.

remove all power. Meter in resistance mode. Measure the resistance to ground of the gate pin. What is the measurement?

Repeat for the resistance to ground on the drain pins. We are checking if either of these pins are shorted to ground.

next, switch the meter to volts mode (dc scale; 30v or higher). Apply the power adapter.

carefully measure the voltage to ground of the following pins on the charger ic:

ACIN pin #1 ; to confirm adapter will be detected
DCIN pin #18 ; to confirm the ic is being powered
ACOK pin # 2 ; output flag for the adapter detection

[Growtopia Jaw]

PQB11: gate - 9.5k ohms
all drain pins - 34k ohms

[mon2]

These resistance to ground measurements are ok. No shorts here.

Continue to debug the charger ic as noted above. Post each measurement. If the charger ic is not defective ; is soldered in place properly; is being powered then the gate voltage should be ~25 volts to enable these 2 dcin mosfets.