Acer A315-41G similar to AN515-42, AC OK Battery OK but not charging

[titomno2]

Hi guys,
I currently trying to figure out why the laptop of my friend did not charge.
It is a Acer AN515-42 (Ryzen 5 2500U), I manage to make it works on AC and battery but no charging.
At first it was not working on Battery, I discovered that PQ201 was knocked off and replace it => work on battery precharged on another computer.
I also checked the small resistors between PQ312 and PQ201 and even if they are ugly values are OK.
My issue, when I plug the charger computer off, it drains 0.25A during few seconds with amber light on (charging) then amber light blinks and 0.00A drain.
I measured the mosfet PQ305, PQ306 and PQ312 and did not find any short (from my perspective).
On infrared camera during the 0.25A consumption I can see PQ305 getting hot, PU301 and PD301 also.
Voltage of the battery was 15.79V and when it "charges" voltage between PQ305 and PQ306 is 15.90V (once charging stops the battery voltage remain at 15.79V).
I checked the 100 Resistor and read 10Ohms => OK
I checked the 0 Resistor and read 0.1 Ohms => OK
I' am a bit confused to determine if the intersil chip 88739A is good (seems to).

What can I check, I already tried to replace the PU301 but the one from the doner board was out of order (to reaction at all, so I swapped back with the old one (and computer works but did not charge).

The battery works (drain and charge on another acer computer and yes it is the same part number AC14B8K.

Any help or advice will be highly appreciated.

Thanks guys for any help you may provide to me.

[mon2]

checked the 100 Resistor and read 10Ohms => OK

??

Remove all power. Meter in lowest resistance mode. Measure the resistance between pins 14 & 15 on the charger IC PU301. You are checking the resistance of the current sense resistor. Measure this directly at the charger IC. Post your measurement.

Next, short your meter probes. Post the resistance measurement with the probes shorted.

[titomno2]

Hi Mon2

I cannot choose the range for the resistance on my meter (it cycle itself from MOhms to Ohms).

I measured directly on the IC but is quite hard as the pitch between pads is very tiny.
I measured between PC319, pins are very small to have a proper measurement, but according to the boardview it should be the same.
Between pins 14 & 15 I read 2.2Ohms to 2.3Ohms.
When I short the probes the readings are between 0.0Ohms and 0.1Ohms.

I understand it is the CSON for CHARGER, but don't know if the value is correct or not (seems low for me).

I put an extract of boardview to be certain I did it properly.
The board wzas out, I removed Battery, AC and the RTC Battery also. Waited few minutes to be sure to have a complete discharge.

As english is not my mothertong, feel free to ask for clarification (my wording is sometimes messy, sorry for that).

[mcplslg123]

Resistance between CSON/CSOP is correct. Check resistance between ACN/ACP also in same way.

[titomno2]

Resistance between CSON/CSOP is correct. Check resistance between ACN/ACP also in same way.

Hi mcplskf123, could you help me to identify the pins on the chip, in the board view I'm not findinf ACN or ACP (I have ACIN_CHG, ACLIM_CHG).

[mon2]

I'm not findinf ACN or ACP

These 2 pins are also known as CSIP and CSIN. Standing for 'current sense input positive' and 'current sense input negative'. The positive pin is where the current enters the circuit and negative is where it leaves in the power path. Between the 2 pins will be a very low resistance resistor known as the current sense resistor. The charger IC is monitoring the voltage that enters and the voltage that leaves and expects a very very small voltage drop. Based on this voltage drop, the charger IC can gauge the amount of load or the current draw imposed by the power rail. If the voltage drop is too high, this equates to too high of a current use so power down the rail's mosfets.

So with no power, measure the resistance between pins 32 & 31 but do so directly at the charger IC pins.

[titomno2]

Thank you mon2,
I have also a reading of 2.1 to 2.2Ohms between pin 31 & 32.

[mon2]

This resistance path check is OK and matches the schematics.

Carefully measure the voltage to ground of each pin on the dual diode @ PD301. When both, the adapter and battery are connected, the higher voltage of these 2 power sources should appear on pin # 1 to power the charger IC.

Confirm the details of this dual diode which may be leaky.

To check in another way, remove all power -> meter in DIODE mode. Red meter probe on pin # 3 and black meter probe to pin # 1. The diode should conduct. Reverse the direction of the probes and the diode should block (OL).

Do the same with pins # 2 & # 1 - same results should follow if the diode is working.

[titomno2]

With adpater (19.3V on stabilized power supply) and battery (15.22V).
Battery plug in => 75mV on #1.
Plugin the AC adpater => 19.03V for few seconds then drop to 18.83V (during 0.25A consumption) and goes back to 19.03V when returning to 0.00A.
Removing the adapter => 15.22V (voltage of the battery).

To complete the figure I have made the measurment in diode mode (everything unplugged):
#3 to #1 0.333V
#1 to #3 OL
#2 to #1 0.333V
#1 to #2 OL

I assume the dual diode is fine.

I replaced the PQ201 from a doner board as I wasn't able to start on a charged battery (don't think it could have a direct influence on charging behavior).

Hope it is helping you to guide me to find the culprit.

Thanks again, explanation are very clear for me.

[mon2]

With adpater (19.3V on stabilized power supply) and battery (15.22V).
Battery plug in => 75mV on #1.
Plugin the AC adpater => 19.03V for few seconds then drop to 18.83V (during 0.25A consumption) and goes back to 19.03V when returning to 0.00A.
Removing the adapter => 15.22V (voltage of the battery).

Confused about the above.

If battery is @ 15v22 and the adapter is @ 19v3, then pin # 1 should be ~19 volts.
If adapter is removed, pin # 1 should be ~15 volts.

Confirm the above details again. Pin # 1 is the output of the dual diodes and the highest voltage should be output to power the charger IC.

[titomno2]

Sorry,
When on battery alone it is 15.22V (value could be lower over time as the battery is discharging).
When I put the adapter the voltage go up to 19.03V and reduced to 18.85V during the few seconds (only during the few seconds I see a current consomption of 0.25A and mosfet PQ305 getting slightly hot in the same time of the ic chip).
Pïn one is the output of the dual mosfet (see picture).

What I find confusing and may be it did not help you is when I plug only the battery only (alone) I have nothing (no voltage neither on pin 1 nor on pin 2 (as I assume only the pin 3 as the adapter voltage).
But once I have plugged in the adapter and remove I have this time the 15.22V of the battery continuously.

May be I am wrong but my first idea is that I should have the 15.22V right when I plug the battery ?

Feel free to ask any clarification.

[mon2]

What I find confusing and may be it did not help you is when I plug only the battery only (alone) I have nothing (no voltage neither on pin 1 nor on pin 2 (as I assume only the pin 3 as the adapter voltage).

This behaviour is not correct for this dual diode. The battery voltage should travel through the diode when it is the only power source. Replace this dual diode with another. It is a common part used by many vendors.

To confirm, the battery voltage MUST be present on pin # 2 and the same voltage should be present @ pin # 1. Something wrong with this diode (most likely) or the traces from the battery to the pin # 2 of this part. You can perform a diode (continuity) check between pin # 2 and the contacts of the battery connector (do not attach the battery in such a test).

[titomno2]

Just tested the continuity between the pin #2 and the positive battery terminal (0.1Ohms, so It is OK).
Changed the dual diode with one from other board and the behavior is exactly the same.

Something I was thinking of is that resistor of the battery temp reading seems damaged not in good shape, should I change them. Could it be an issue of reading the battery temperature sensor that stopped the charging ?
As the ic can not read the temperature sensor it shut down everything to avoid damage ?

[mon2]

Something I was thinking of is that resistor of the battery temp reading seems damaged not in good shape, should I change them. Could it be an issue of reading the battery temperature sensor that stopped the charging ?

YES!! That should be the # 1 step. As Louis shows in his countless videos, always inspect the board for puke / cat urine, etc. that may have caused parts to be defective.

[titomno2]

So I changed the 3 resistors PR202 (100Ohms) PR203 (1kOhms) and PR204 (200kOhms) (I'm confuse the pdf indicate 200kOhms on the PR203, but I read 1kOhm on the resistor removed and the same value on the resistor from the doner board).
Whatever the behavior of the board is still the same.

I have notice #2 in PR203 have the 3.3V only fews seconds and drop at 156mV when charge stop and orange light start to blink.
PR201 is 100Ohms, PR202 is 100Ohms.
Did not find any component on which the Louis Rossman cat may have piss on :-D.

I think the issue is not far but I running out of new Idea.
Is to bad because the computer start on battery, on ac, on battery and ac but doesn't charge which is a bit disappointing.

[mon2]

What is the voltage to ground of the gate pin # 2 of PQ201 ?

[titomno2]

With battery plugged in and ac adapter, I measured 2.947V steady on pin #2 of PQ201.
The value not vary much whatever the consumption is (0.25A or not).

[titomno2]

I have order the ISL chip (just in case) and also the mosfet for PQ201 (as I am not very confident with the doner board health).
PQ201 are cheap, but on two other motherboard a defective one was preventing the board from booting up (seems a quite fragile part).

Until parts receiption I will wait for any comment from you guys if I have anything to check again to fix this charging issue.
On windows the batttery reading are OK and the plugin logo show up when I plug the charger but no charging rate visible (which is ok as we can see on the different measurement).

Thank you.

[mon2]

Measure the voltage to ground of the following points of interest with both, the power adapter & battery connected:

ACIN_CHG ; pin 1 on PU301
AC_OK ; pin 2 on PU301
ASGATE ; pin 30 on PU301

If the power adapter is above a certain threshold voltage on pin # 1 (ACIN_CHG), then AC_OK will be floating and should be a logic '1' state and ASGATE will be boosted to drive the 2*DCin mosfets.

[titomno2]

ACIN_CHG ; pin 1 on PU301 => I read 2.206VDC (quite stable)
AC_OK ; pin 2 on PU301 => I read 3.26 to 3.27VDC (fluctuating)
ASGATE ; pin 30 on PU301 => I read 24.44VDC (Boosted OK)

Fun fact (or not) I have made the measurement a first time with battery RTC plugged in, Battery plugged in and power adapter (the amber light is blinkin right away).
I the RTC is not plugged in I have the 0.25A consumption for few seconds and amber light steady before going donw to 0.00A and blinking amber light.

But it doesn't change the measurements (except on mV scale, which I think we could ignore)