ACER V3-472 Battery charging problem

[String2016]

I have this acer V3-472 laptop with board id DA0ZQ0MB6E0 REV:E , With battery charging problem, At first I thought it was a bad battery so, I bought new battery but the problem still the same,cannot turn on with battery only and when battery and charger plugged in no orange light indicator but the laptop is working properly with charger only plugged in. here is the measurement.I noticed when battery and charger both plugged in the voltage on current sense resistor PR1 is fluctuating form 19v go down but when charger only plugged in its working fine here is the measurement of PU1 BQ737 when battery and charger both plugged in.


acdet pin 6=2.6v
acok pin 5=3.3v
vcc pin 20=19v
regn pin 16=from 7.9v goes flustuate to 7.2v
BTST PIN 17=From 7.5 flustuate to 7v
hidrv pin 18=1.4v
phase pin 19=1.4v
lcdrv pin 15=2v

I noticed also when battery and charger both plugged the first dc mosfet PQ1 GATE PIN 4 is fluctuating voltage

anyone can help me on this please

[mon2]

Re: ACER V3-472 Battery charging problem

REGN is too high. It is typically ~6 volts.

Confirm your meter accuracy and is with fresh batteries.

[String2016]

Re: ACER V3-472 Battery charging problem

yes its with fresh batteries and multimeter is accurate tried also other multimeter is fluctuating on regn 7.9 to 7v fluctuate

[String2016]

Re: ACER V3-472 Battery charging problem

gate of pq1 is fluctuation when battery and charger plugged in same with PD2 PC3 AND PC4

[mcplslg123]

Re: ACER V3-472 Battery charging problem

Voltage on all pins of PQ3?? Resistance on PQ1 beween pin1-4/pin1-8/pin4-8??

[String2016]

Re: ACER V3-472 Battery charging problem

PQ3 measurement with battery and charger plugged in
pin1=19.8v
pin 2= from 19.8v to 17v fluctuate
pin3 =same voltage with pin2 fluctuate
pin 4=0v
pin 5=0.30v fluctuate
pin 6=from 3.4v to 6v fluctuate

pq1 resistance no battery and chrger plugged in
pin 1to 3 = 7megaohms goes down fluctuate
pin 4= 229k
pin 5 to 8=26.5k

[String2016]

Re: ACER V3-472 Battery charging problem

I cheched pq4 also pin3 pr8 and pr4 both resistor have same value reading as per schematic

[String2016]

Re: ACER V3-472 Battery charging problem

I Noticed also PR22 the resistor on the board is 2.2ohms but on the schematic is 4.7

[String2016]

Re: ACER V3-472 Battery charging problem

anyone could help this please

[mon2]

Re: ACER V3-472 Battery charging problem

My first suggestion is to replace the charger IC. Then check REGN voltage again. The part is not expensive on AliExpress. Buy a few along with the dcin mosfets. The voltage on REGN is too high..should be 6 volts.

[String2016]

Re: ACER V3-472 Battery charging problem

@mon2 replacing charging ic solved the problem regn voltage now is stable of 6v and charging orange light show up but checking pq1 no pin4 gate no voltage pq2 gate voltage is present at 19v

[String2016]

Re: ACER V3-472 Battery charging problem

and the problem is cannot power on with battery only and the charging is not going up

[String2016]

Re: ACER V3-472 Battery charging problem

I checked again battery plugged in and charger plugged in PQ1 have gate voltage of 9v can power on but on the charging not goes up, but when battery only plugged in no voltages on pq1 pin4 gate already replaced pq1 come from scrapboard mosfet with good reading

[String2016]

Re: ACER V3-472 Battery charging problem

I checked resistor PR6 AND PR3 its measures only 80k supposed to have 220k

[mon2]

Re: ACER V3-472 Battery charging problem

Ok. Good to hear of some progress.

See attached.

Measure the voltage to ground of PQ1 GATE pin # 4 when ONLY the battery is used. The battery should be charged enough to power the board.

Also measure the voltage to ground of PQ3 GATE pin # 4 when ONLY the battery is used.

Each is a P-channel mosfet so the GATE voltage must be LOWER than the voltage being passed between SOURCE / DRAIN pins.

Respectively, if the BATTERY ONLY is the power source, then PQ3 GATE should be a lower voltage = 0 volts since 2N7002 mosfet should be ON @ PQ4.

In this same case, PQ1 gate voltage should be high enough to DISABLE PQ1 mosfet (often the same voltage as the voltage on the source/drain pins) to force the DISABLE.

Confirm also the voltage to ground of the ACDET pin #6 again. Measure WITH the external adapter and without the external adapter.

PR6 AND PR3 its measures only 80k supposed to have 220k

That is ok as the ratio remains the same. That is with equal resistance on the high and low sides, the input voltage will be 50% at the junction of the 2 resistors. That is low enough to ENABLE the P-channel mosfet.

[String2016]

Re: ACER V3-472 Battery charging problem

thanks for the response measured PQ1 BATTERY only plugged in with 71percent charge there is no voltages on pin 4 gate of pq1 and on the pin 4 of pq3 no voltages

the acdet charger only plugged in pin number 6 2.6v

[String2016]

Re: ACER V3-472 Battery charging problem

checked pq3 pin 5 battery only no voltage shown

[String2016]

Re: ACER V3-472 Battery charging problem

both no voltage on pq3 pin 5 even charger only plugged in or battery only or both , pq4 pin 2 no voltage also

[String2016]

Re: ACER V3-472 Battery charging problem

I Noticed PQ1 pin 4 gate voltage present if charger only plugged in and both charger and battery plugged in, but when battery only plugged in no voltage on gate pin 4 of pq1

[mon2]

Re: ACER V3-472 Battery charging problem

What is the voltage to ground of ACOK# (pin 5) with only the power adapter? With only the battery?

Confirm the voltage of the battery at the battery contact. This same voltage must appear at PQ2 mosfet (aka battery mosfet) = my bad, corrected this label.

About to get some beauty sleep but continue to check the following...

1) The KBC / EC device monitors the power adapter presence by the ACOK# signal. If the ACOK# = LOW = adapter voltage is OK. This turns the dual MOSFETS @ PQ6 OFF.

2) With PQ6 mosfets OFF (due to gate voltage being LOW on the 2N7002), the pull-up resistors @ PR14 and PR12 should output a '1' = 3v3 from the +3VPCU rail. Confirm these voltages.

3) Based on this status, the KBC/EC should drive the D/C# pin to enable / disable the proper mosfets to allow for the adapter to power the logic board if present. Or, disable the DCin mosfet (PQ1) but ENABLE the battery mosfet @ PQ2 by turning ON the 2N7002 @ PQ4. PQ4 will turn ON if D/C# = '1' = high = ~3 volts. Once PQ4 is ON, the ground connection is made on PR8. This results in PR8 & PR4 creating a voltage divider to LOWER the gate voltage on PQ2. This LOWER gate voltage turns ON the P-channel battery mosfet @ PQ2 to allow the battery to power the logic board.

4) PQ3 is acting like an inverter triggered by the D/C# signal. If PQ1 is ON, PQ2 is OFF. If PQ2 is ON, PQ1 is OFF.

5) Also interested in the SMBUS signal voltage to ground on the battery pack:

MBCLK
MBDATA

Meter in DC volts (10 volts or higher is ok). Red probe on signal to measure. Black to ground (shield is ok). Post each measurement.

Each line should be ~3 volts if the line is not stuck. If the voltage is 0v or just a low voltage, close to zero then check again in DIODE mode.

Meter in DIODE mode, red meter probe - yes red to GROUND.
Black meter probe to the point to test.

What is the measurement ? If close to 0 volts then the line is being pulled down by some component.

Often the ESD devices near the battery pack get killed. That is, inspect / remove the ESD device @ PU2 and then measure again.

If the SMBUS line(s) are stuck, the battery pack cannot be detected and the battery will not be charged since it is not 'visible' to the logic board.

I Noticed PQ1 pin 4 gate voltage present if charger only plugged in and both charger and battery plugged in, but when battery only plugged in no voltage on gate pin 4 of pq1

That makes sense, since diode @ PD1 will block a reverse voltage to PQ1. That is, when the BATTERY ONLY is powering the logic board, the battery voltage should appear @ VIN (pins 1-2-3 of PQ2).

The PD2 diode orientation will block this VIN voltage from reaching pins 5-6-7-8 of PQ1.

More concerned about if the battery mosfet is being enabled or not. Wasted the day fixing an A1534 (piece of !@#*(*& design) so seeing doubles. Even with our amazing new microscope (4k resolution) - without it, I think I would have soldered my thumbs. Need to get some rest. Post your updates.