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

[mon2]

Pin #1 voltage is considered to be low. It should be 2v4 or higher. Compare this voltage on the laptop that is working.

[titomno2]

Ok I think I understand your point, I have measured before the Vin at 19.3V and checked the PR306 resistor which is 0.510MOhms (normally it should be a 499kOhms at 1% so the resistor is slightly Off tolerances).
I will try to make the measurement on the laptop working (but it is not the same board I have to check if the battery management is similar or not).

[titomno2]

I'm sorry the laptop in which I can charge the battery is quite different. Only think I can notice is when I plug only the battery.
It is the same battery i use for both, withou adapter:
When I plug the battery in the laptop that can charge, right away the battery is activated (I have 15.2V).
When I plug the battery in the laptop that cannot charge, the battery is not activated (I have 150mV).
Once the adapter is plugged in.
In the laptop that can charge, I have 1.35A immediately (and voltage increase while charging current slowly decrease).
In the laptop tha cannot charge, I have 0.00A voltage of the battery is activated and remain activated.

So I'm quite consufe as I assume that normaly when plugged in the battery should be activated right away on both laptop.
I did not try to fire the non charging one without adapter at first (it could help to understand where is the signal lost that prevent the proper charging).

I'm learning a lot, thank you for your help

[titomno2]

PQ201 blow up... I am not able to replace it as I did not have any good available for the moment... I will have to wait...

[titomno2]

Any of you know what I may use to replace the LBSS139LT1G, I can't find easily except on aliexpress (still afraid to buy cheap reproduction).
I have seen the LBSS138LT1G but it appears not to have the same schematic inside.

Any help will be very much appreciated

[mon2]

Consider to use the 2N7002 n-channel mosfet. These are very common and easy to source (no pun).

[titomno2]

Thank you again mon2, Indeed much more easy to find on local reseller. Just for my understanding, I understood that PQ201 is somehow an heritage from the board including a switch preventing battery usage when the bottom cover is removed (not populated on my boards).
So If I solder a jumping wire between the pin #3 and pin #1, I should have the same behavior than for an activated mosfet (is there any risk do you think ?).
Of course I have to ckeck if the rest of the circuit is all right.
Without PQ201 the boards works but of course battery is not activated (detected but not working).
I'm a little bit confuse by why they have introduce such design (they removed the switch as it was creating a lot of trouble when plastic and foam pushing getting loose when ageing.

[titomno2]

Thank you again mon2, Indeed much more easy to find on local reseller. Just for my understanding, I understood that PQ201 is somehow an heritage from the board including a switch preventing battery usage when the bottom cover is removed (not populated on my boards).
So If I solder a jumping wire between the pin #3 and pin #1, I should have the same behavior than for an activated mosfet (is there any risk do you think ?).
Of course I have to ckeck if the rest of the circuit is all right.
Without PQ201 the boards works but of course battery is not activated (detected but not working).
I'm a little bit confuse by why they have introduce such design (they removed the switch as it was creating a lot of trouble when plastic and foam pushing getting loose when ageing.

Small update, I use a shnt between pin #3 and pin #1
It works perfectly on my AN515-52 which have the same issue as the A315-41G => power on battery, on Adapter and charging properly.
It works not perfectly on my A315-41G => power on battery, on adapter but still no charging.

Battery used is the same for both motherboard.
I have tried to downgrade BIOS now the battery is recognized properly, v1.18 to v1.17 then back again to v1.18 (touchpad works again, keyboard is strange (but I assume that formating is different as when I look to the touch they are not at the same position betwen ASPIRE 3 and NITRO 5).

So I think I have still an issue with something elsewhere on the A315-41G board.

I will share with you my progress if it can help anybody else.

So if you have an AN515-52 or A315-41G (soon I will do the same with AN515-42) that not start and nothing is obvious on the board.
Remove the PQ201, if it start properly on adapter, you have found the issue.

[titomno2]

PU301 replaced by a brand new one tested on another motherboard PQ201 replaced by a new one => start with battery, start with adapter but still no charging.
Change both of the mosfet => No change, not charging.

I have to circle back to the intial measurment to check if I did not miss something somewhere.

[mon2]

1) Visit a friendly priest.

2) carefully measure the voltage to ground of each pin on the charger ic with both adapter and battery connected.

[titomno2]

Hi, Unfortunately i don't know any friendly priest (and I shoul ask for what type of action (1a exorcism or 1b funeral)).

So I tried the option 2 (Computer was OFF during the measurement and with batterie and adapter plugged in).
I'm confuse by the reading of NXXXXXX and PROG_CHG and COMP_CHG reading at 0.000V (I may try to do it on computer running).
01 ACIN_CHG 2.216V
02 ACIN 3.144V
03 N16860647 3.286V
04 N16860655 3.288V
05 N16860695 0.000V
06 AMON_ISL95520 0.000V
07 N46981745 0.000V
08 N46981759 0.000V
09 PROG_CHG 0.000V
10 COMP_CHG 0.000V
11 CCLIM_CHG 1.704V
12 FSET_CHG 0.000V
13 N16860560 157mV
14 CSON_CHG 15.74V
15 CSOP_CHG 15.74V
16 ACLIM_CHG 1.474V
17 N16860799 1.004V
18 N16860474 19.16V
19 VDD_CHG 5.14V
20 VDDP_CHG 5.14V
21 LG_CHG 0.000V
22 LX_CHG 15.74V
23 UG_CHG 15.71V
24 BST_CHG 15.46V
25 BGATE_CHG 13.65V
26 VBAT_CHG 15.73V
27 OPCP_CHG 16.92V
28 OPCN_CHG 11.79V
29 CMSRC_CHG 19.45V
30 ASGATE_CHG 24.52V
31 CSIN_CHG 19.51V
32 CSIP_CHG 19.51V

[mon2]

Remove all power. Meter in resistance mode.

Measure the resistance between pins 3 and 4 but measure directly at the charger ic pins.

What is the measurement?

[titomno2]

I read 4.38kOhms

[mon2]

This is a very high measurement. Be sure that you are measuring on the proper pins.

Compare the resistance against the schematics. There is a defect here and this is the root cause of your issues.

Post clear pics of the resistors that are on these pins.

Be sure that the adapter and battery are disconnected!!!

[titomno2]

Yes of course, all measurement where done without any power on the board, (no battery and no adapter).
So I have checked but in front of pin#3 en pin #4 there is no resistance (PR316 and PR314 not polated (circuit is continuous).
On pin #4 PR316 is linked to the PR202 (100K according to pdf and I read 100.2kOhms with the multimeter)
On pin #3 PR314 is linked to the PR201 (100K according to pdf and I read 100.5kOhms with the multimeter)

I have also check R1577 and R1574 both are close to the 2.2kOhms presented => if I read between R1577 and R1577 I found 4.38kOhms so could it be a super IO chip issue ? Short circuit on this two lines?
On another super IO I read OL on the same point !!!

[mon2]

Pins 2 & 3 are SMBUS lines - these measurements for the voltage to ground are ok. Was originally concerned that they were in the power path and there is a voltage drop.

Update

The parked voltage on these SMBUS lines is ~3v3 which is ok and this means the lines are not shorting to ground.

As a final test of these lines, remove all power, meter in diode mode. Short your meter probes and the meter will tone beep. One meter probe onto pin #2 of the charger IC and other meter probe onto the EC controller pin that should mate with the same line. The meter should tone beep which means the trace between the 2 points is not defective.

Repeat the same test with pin # 3 of the same SMBUS line to the EC.

Sharing the partial charger circuit for the board.

[mon2]

Check the voltage to ground of +RTCVCC

[titomno2]

Really challenging, I was hoping to be Shiva.
So in diode mode on pin #2 of the IC (ACIN) and pin What to test with??? of the EC chip I read 0.9Ohms (and it bip).
on pin #3 of the IC (N16860647) and pin Abit BP6 recapping & stability tips [UPDATED] of the EC chip I read 1Ohm (and it bip also).
So the trace seems to be OK.

Regarding the +RTCVCC the value is strange, I have 2.77V when I check on the coin cell I have 3.08V and it drop after DC1 (3.08V on pin #2 and only 2.77V on pin #1). I found the voltage drop quite important.

I hope I understand clearly your instruction and don't make loose your time. I hope also it may help someone else.

[mon2]

What are the markings on your battery? The battery charge mosfet area notes 17v4. Is that the battery pack you are using?

21 LG_CHG 0.000V

Does not look correct. Has the mosfet @ PQ306 been replaced?

[titomno2]

Battery is AC14B8K genuine acer model 4cells 15.2V (max charging is 17.4V 4×4.2V = 16.8V so to my point of view it is OK).
Yes, I change the PQ306, but maybe I did not solder it properly. I should check that next evening.
I don't remember to have checked any brigde between gate and drain nor betwen drain and source. (not good).
On picture solder not seems to be so bad but sometime the mess is hidden under.