Acer A315-55G / DA0ZAWMB8E0 not charging [SOLVED]

[vannix]

Re: Acer A315-55G / DA0ZAWMB8E0 not charging

in resistance mode all measurement result in infinite resistance. by exciting the gate of both fets with another tester in diode mode they measure about 1ohm in source-drain, so PQ1 and PQ9054 seems ok.
the voltage are the following:

PQ1 pin 4 gate = 0.1v
PQ1 pin 1-3 source = 0.2v
PQ1 pin 5-8 drain = 19,6v

PQ9054 pin 4 gate = 0.2v
PQ9054 pin 1-3 source = 0.1v
PQ9054 pin 5-8 drain = 0.2v

i think the problem is still related to the bq24780s

EDIT: ACOK is 0V, but vcc and acdet are ok, so the problem is still related to the battery charger.. chinese ic fails??

[mon2]

Re: Acer A315-55G / DA0ZAWMB8E0 not charging

2.7v on acdet but, again, there is no 19v after PQ1

Good value of ACDET. The PQ1 is a different fault and is very common.

Remove all power. Meter in resistance mode.

Check the resistance across the mosfet pins to check if it is defective.

Source (1-2-3) & Drain (5-6-7-8)
Source (1-2-3) & Gate (4)
Gate (4) & Drain (5-6-7-8)

Post the above readings for PQ1 and then again for the next mosfet that follows. A low reading = defective mosfet.

Next, measure the voltage @ GATE of each of the first 2 mosfets.

Recommend to do the above with NO POWER (NO BATTERY). When checking the gate voltage - do so with only the external power adapter.

The good value of ACDET is now informing the charger IC that a valid power adapter is mated to the logic board. This will allow us to move forward.

[vannix]

Re: Acer A315-55G / DA0ZAWMB8E0 not charging

What is the voltage @ pin #2 of the PQ17 mosfet ?

It appears to be checking the voltage of the ADP_ID pin and is used to turn ON the mosfet @ PQ17 but that would then cause the ACDET pin to be pulled to 0V.

Measure the ADP_ID voltage on pin # 2 so we can review.

pq17 is not shorted and ADP_ID is 9,3v (1/2 of VA), i can find it also in the dc connector.
i dont understand what it does, the dc connector only has + and -, it hasn't ID pin.
The voltage of 9v is given by the voltage divider on the board, so it has no contact with the connector. The only explanation i think is that the connector is broken and must have a return on the adp-id when a connector is plugged in (like the sense of the audio jack)

EDIT: the dc connector is broken. there is a bent pin that does not make good contact with ground when the connector is inserted. manually shorting apd_id to ground results in about 2.7v on acdet but, again, there is no 19v after PQ1

[mon2]

Re: Acer A315-55G / DA0ZAWMB8E0 not charging

What is the voltage @ pin #2 of the PQ17 mosfet ?

It appears to be checking the voltage of the ADP_ID pin and is used to turn ON the mosfet @ PQ17 but that would then cause the ACDET pin to be pulled to 0V.

Measure the ADP_ID voltage on pin # 2 so we can review.

[vannix]

Re: Acer A315-55G / DA0ZAWMB8E0 not charging

Good link with the new resistor values.

1) You can use the above calculator to validate any resistor combination.

2) The key point is to use the same ratio of the resistors to hit the target voltage.

3) See attached. Your link validates the same. Ok to use the new resistor values you have from your donor board.

same result with new resistors.. 0v on pin 6. but now i'm sure that the resistor value are correct.
the problem could be PQ17 (what does that circuit do?? i'm thinking of removing it...)

[mon2]

Re: Acer A315-55G / DA0ZAWMB8E0 not charging

Good link with the new resistor values.

1) You can use the above calculator to validate any resistor combination.

2) The key point is to use the same ratio of the resistors to hit the target voltage.

3) See attached. Your link validates the same. Ok to use the new resistor values you have from your donor board.

[vannix]

Re: Acer A315-55G / DA0ZAWMB8E0 not charging

The above are bad values. Start with ACDET.

1) This is a voltage that is based on the DCIN (adapter) voltage that will enter a resistor based voltage divider to lower the DCIN voltage to a safe voltage for the charger IC.

See resistors PR31 & PR211. Each must be present and each must be the value shown in the schematic.

2) Meter in DC volts mode (20V is ok).

3) Red meter probe to PR31 -> either side -> black meter probe to ground.

What is the voltage reading ?

Then move the red meter probe to the other side of PR31.

Post your measurements.

If adapter is working then you should have ~19V coming in -> this voltage should be present on one side of PR31.

Confirm it.

Then the LOWER voltage should appear on pin # 6 of the charger IC = ACDET.

Reference:
https://ohmslawcalculator.com/voltag...der-calculator

hi, and thank you for your reply. i would like to tell you that last friday i had already checked the voltage divider and it seemed quite correct (doing the calculation with the ohm values read by the tester should have been about 2.3v). I had therefore assumed that the 24780s had an effect on this voltage divider (with an internal resistance to ground).
this morning i unsoldered the resistances to make the most precise measurement and pr31 seems to be open. I don't know if it was damaged in the tests or if it was already broken.

pr31: 0v --- 19,6v
pr211: 0v --- 0v

pr31: 1m (friday i read 920k)
pr211: 129k (friday i read 130k)

pr31 removed: 3m
pr211 removed: 136k


i don't find 866k R in donor boards, do you think it's safe for test to change pr31 with 422k and pr211 with 66.5k?


EDIT: according to this pdf it seems ok, i'll try asap... https://www.badcaps.net/forum/showpo...12&postcount=2

[mon2]

Re: Acer A315-55G / DA0ZAWMB8E0 not charging

pu1 pin 4 acdrv is 0.5v
pu1 pin 5 acok is 9.6v
pu1 pin 6 acdet is 0V

The above are bad values. Start with ACDET.

1) This is a voltage that is based on the DCIN (adapter) voltage that will enter a resistor based voltage divider to lower the DCIN voltage to a safe voltage for the charger IC.

See resistors PR31 & PR211. Each must be present and each must be the value shown in the schematic.

2) Meter in DC volts mode (20V is ok).

3) Red meter probe to PR31 -> either side -> black meter probe to ground.

What is the voltage reading ?

Then move the red meter probe to the other side of PR31.

Post your measurements.

If adapter is working then you should have ~19V coming in -> this voltage should be present on one side of PR31.

Confirm it.

Then the LOWER voltage should appear on pin # 6 of the charger IC = ACDET.

Reference:
https://ohmslawcalculator.com/voltag...der-calculator

[vannix]

Hi, i need help in troubleshooting this board. with battery it works normally, but it does not charge battery.
The owner reports that the pc has fallen to the ground from the side of the dc connector. the pc did not shut down but from that moment it stopped charging the battery.
it uses a 24780s that has already been replaced without any changes (replaced 2 times, first time with a used one and then with a new one from china).
the 24780s (pu1) is powered but does not open the PQ1 mosfet.

pu1 pin 4 acdrv is 0.5v
pu1 pin 5 acok is 9.6v
pu1 pin 6 acdet is 0V
pu1 pin 28 vdc is 19.3v

pq1 pin 4 gate = 0.2v
pq1 pin 1-3 source = 0.9v
pq1 pin 5-8 drain = 19,3v


does anyone have any suggestions?
thank you

schematic & boardview: https://www.badcaps.net/forum/showth...ht=DA0ZAWMB8C0