ACER TimelineX 4830TG not charging

[Nze123]

Hi folks,

I am having a charge issue with a Acer TimelineX 4830TG-2434G75Mnbb laptop motherboard (LA-7321P rev1.0, model no P4LJ0).
The PC is booting and running OK on battery, but when I plug the AC adapter, I have no charge led and the battery does not charge (whether system on or off). Windows 10 shows the PC appears on battery mode.

I checked the charging port and the power rail through the DC-IN mosfets ; the 19.3V is available up to the B+ port. The gates of the 2 Mosfets is 25,2V.
I changed the original battery for a new battery ; charged at 11V.
Note: The JDOOR1 auxiliary board is connected to the motherboard with PWR ON set (battery active).

Somehow the BQ24725 (PU1) charging circuit looks inactive ; I noted the following voltages on the pins (AC adapter and battery connected, system off), which seem to comply with the standard application circuit

PIN1 1,2,3 : 19,34V
PIN4: 25,6V (ACDRV)
PIN5: 3,3V (ACOK)
PIN6: 2,7V (ACDET)
PIN7: 0V
PIN8,9: 3,3V (SMBUS)
PIN10: 0,8V (ILIM)
PIN11,12: 10,96V
PIN13: 11,01V
PIN14,15: 0V
PIN16: 5,99V
PIN17: 10,72V
PIN18: 10,93V
PIN19: 11,01V
PIN20: 19,05V


The battery driver mosfet is blocked (11V on one side, 19V on the other)
No sign of liquid damage or heated component in the area
Any idea what may be causing this issue and where to look ?

Thanks in advance for guidance.

[mon2]

Re: ACER TimelineX 4830TG not charging

1) Confirm the voltages for the SMBUS (I2C) interface for the battery:

EC_SMBDA
EC_SMCA

these are the pins on the battery connector and after the current limit resistors (100 ohms; 0402).

2) Remove all power. Meter in resistance mode (2k should be fine).

Check and post the resistance for the following - checking for damaged mosfets:

source & drain
source & gate
gate & drain

for PQ6, PQ7, PQ8, PQ9, PQ10.

Reference:
http://electronicsbeliever.com/how-t...-is-defective/

See the table on this website.

[Nze123]

Re: ACER TimelineX 4830TG not charging

Thanks for the insight ; nice link by the way...

1) EC_SMB_DA1 and CK1 are both 3.3V on the battery side as well as after current limiting resistor (pin 8&9 of BQ24725)

2) Resistance check 2kR (S/D, S/G, G/D)
PQ6 na / na / na
PQ7 na / na / na
PQ8 na / na / na
PQ9 na / na / na
PQ10 na / na / na

Diode check (S/D)
PQ6 0,527V
PQ7 0,520V
PQ8 0,484V
PQ9 0,485V
PQ10 0,502V
(all na on reverse)



3) I queried battery SMBUS data (battery standalone) using an Arduino:
17:07:39.716 -> Manufacturer Name: Panasonic
17:07:39.716 -> Device Name: AS11A5E
17:07:39.763 -> Chemistry LION
17:07:39.763 -> Design Capacity: 4400
17:07:39.763 -> Design Voltage: 10800
17:07:39.763 -> Manufacture Date (Y-M-D): 2021-1-28
17:07:39.763 -> Serial Number: -23263
17:07:39.763 -> Specification Info: 49
17:07:39.763 -> Cycle Count: 1
17:07:39.763 -> Voltage: 11.02
17:07:39.763 -> Full Charge Capacity: 4400
17:07:39.763 -> Remaining Capacity: 1863
17:07:39.763 -> Relative Charge(%): 43
17:07:39.763 -> Absolute Charge(%): 43
17:07:39.763 -> Minutes remaining for full charge: -1
17:07:39.763 -> Cell 1 Voltage: 3674
17:07:39.763 -> Cell 2 Voltage: 3679
17:07:39.763 -> Cell 3 Voltage: 3672
17:07:39.810 -> Cell 4 Voltage: 0
17:07:39.810 -> State of Health: 100
17:07:39.810 -> Battery Mode (BIN): 0b110000010000001
17:07:39.810 -> Battery Status (HEX): 0xC0
17:07:39.810 -> Charging Current: 1770
17:07:39.810 -> Charging Voltage: 12600
17:07:39.810 -> Temp: 27.85
17:07:39.810 -> Current (mA): 0

4) I also managed to snif SMBUS traffic on the motherboard by listening on the battery SMBUS pins (battery and AC adapter connected):

17:23:57.187 -> 16+ 19+ 17+ 30+ 2A-
17:23:57.187 -> 16+ 0A+ 17+ 00+ 00- (current : 0)
17:23:57.187 -> 16+ 0B+ 17+ 00+ 00- (avg current : 0)
17:23:57.187 -> 16+ 09+ 17+ 10+ 2B- (voltage : 11,024 )
17:23:57.187 -> 16+ 14+ 17+ EA+ 06- (charging current : 1,77A )
17:23:58.086 -> 16+ 18+ 17+ 30+ 11- (design capacity : 4400)
17:23:58.086 -> 16+ 1B+ 17+ 3C+ 52- (manuf.date : )
17:23:58.086 -> 16+ 1C+ 17+ 21+ A5- (serialno : 42273)
17:23:58.086 -> 16+ 20+ 17+ 09+ 50+ 61+ 6E+ 61+ 73+ 6F+ 6E+ 69+ 63- (Panasonic)
17:23:58.086 -> 16+ 21+ 17+ 07+ 41+ 53+ 31+ 31+ 41+ 35+ 45- (AS11A5E)
17:23:58.086 -> 16+ 00+ 17+ 00+ 00-

17:23:58.086 -> 16+ 16+ 17+ C0+ 00- (status : 0xC0)
17:23:58.086 -> 16+ 0D+ 17+ 2B+ 00- (Relative charge : 43%)
17:23:58.930 -> 16+ 15+ 17+ 38+ 31- (chg voltage : 12,6V)
17:23:58.930 -> 16+ 08+ 17+ BC+ 0B- (temperature: 30,04)
17:23:58.930 -> 16+ 0F+ 17+ 46+ 07- (remaining capacity : 1862)
17:23:58.930 -> 16+ 10+ 17+ 30+ 11- (full capacity: 4400)
17:23:58.930 -> 16+ 03+ 17+ 81+ 60- (mode: x6081)
17:23:58.930 -> 16+ 0A+ 17+ 00+ 00-
17:23:58.930 -> 16+ 0B+ 17+ 00+ 00-
17:23:58.930 -> 16+ 09+ 17+ 0F+ 2B-
17:23:59.818 -> 16+ 14+ 17+ EA+ 06-
17:23:59.818 -> 16+ 00+ 17+ 00+ 00-
17:23:59.818 -> 16+ 17+ 17+ 01+ 00- (#cycles : 1)
17:23:59.818 -> 16+ 3F+ 17+ 5A+ 0E-
17:23:59.818 -> 16+ 3E+ 17+ 5F+ 0E-
17:23:59.818 -> 16+ 3D+ 17+ 57+ 0E-
17:23:59.818 -> 16+ 3C+ 17+ 00+ 00-
17:23:59.818 -> 16+ 40+ 17+ 17+ 17-
<pattern repeating>
17:24:11.666 -> 16+ 16+ 17+ C7+ 00- (status : 0xC7)
17:24:11.666 -> 16+ 0D+ 17+ 2B+ 00-
17:24:11.713 -> 16+ 15+ 17+ 38+ 31-
17:24:11.713 -> 16+ 08+ 17+ BC+ 0B-
17:24:11.713 -> 16+ 0F+ 17+ 46+ 07-
17:24:11.713 -> 16+ 10+ 17+ 30+ 11-
17:24:11.713 -> 16+ 03+ 17+ 81+ 60-
17:24:11.713 -> 16+ 0A+ 17+ 00+ 00-
17:24:23.555 -> 16+ 0B+ 17+ 00+ 00-
17:24:23.555 -> 16+ 09+ 17+ 0F+ 2B-
17:24:23.555 -> 16+ 14+ 17+ EA+ 06-
17:24:23.555 -> 16+ 00+ 17+ 00+ 00-
17:24:23.555 -> 16+ 17+ 17+ 01+ 00-
17:24:23.555 -> 16+ 3F+ 17+ 59+ 0E-
17:24:23.555 -> 16+ 3E+ 17+ 5F+ 0E-
17:24:23.555 -> 16+ 3D+ 17+ 57+ 0E-

I noted there is no traffic using the slave address 0x12 or 0x13 (charger IC)
Any insight ?

Thanks in advance for the help

[mon2]

Re: ACER TimelineX 4830TG not charging

Well done on the SMBUS sniffing !! Brilliant and very helpful.

So the BMS of the battery is chatting back and reporting its stats.

Do you see any attempts to chat with the charger IC at the noted address?

See attached.

From the posted voltage readings, the conditions should be met to enable the SMBUS communications.

Any sign of corrosion or liquid damage? Consider to flux the PU1 device and apply enough heat to reflow the part. Make it 'dance' as Louis says in his videos. Just be careful to not blow away any support tiny SMD parts.

The same SMBUS connections for the battery are common to communicate with PU1 so it should work if the host is initiating dialog with the slave ID of 0x12 (according to the TI datasheet).

The voltages look good except for pin 11 & 12.

To turn the battery mosfet @ PQ8 ON, the gate voltage (BATDRV) must be 6 volts above the SRN pin. See attached from the datasheet.

Connect the battery - leave out the ac adapter. What are the voltage readings of PQ8 mosfet ? Is the gate truly 6 volts higher than the SRN pin of the PU1 charger IC ? Only then, the battery should power the logic board.

Also, confirm the values of the series current sense resistors linked to the battery on SRN & SRP pins of PU1. Are they indeed matching the schematic values ?

[Nze123]

Re: ACER TimelineX 4830TG not charging

Yes indeed, both the battery and SIO seem to chat together. And the battery looks healthy from the readings.
What I don't know is whether the series of 0x3C through 0x40 returns expected values (manufacturer specific codes, or undocumented).
OptionalMfgFunction4 0x3c r/w word
OptionalMfgFunction3-1 0x3d-0x3f r/w word
Besides the "manufacturer access" returns 0, which I am not sure how it is interpreted by the host.

Also, I see the Battery Status oscillates between 0xC0 (INITIALIZED/DISCHARGING) and 0xC7 where the 7 is a code "unknow error", as per appendix C of https://cdn.badcaps-static.com/pdfs/...5caaff9927.pdf. Might this be due to perturbations on my sniffing the bus ?

As far as I can see, no sign of traffic directed to the charging IC slave (address 0x12 write, 0x13 Read), whether from the Host or from the Battery acting as master (§6 of SMBUS data specification), however long I wait.

Smart Battery Master Functions
Master Functions Code Access Data
ChargingCurrent (to Smart Battery Charger) 0x14 w mA
ChargingVoltage (to Smart Battery Charger) 0x15 w mV

Those function codes 0x14 and 0x15 are indeed exchanged on the bus with suitable values, but with the slave adress 0x16 / 0x17 which correspond to the battery (?)
17:23:57.187 -> 16+ 14+ 17+ EA+ 06- (chg current : 1,77A)
17:23:58.930 -> 16+ 15+ 17+ 38+ 31- (chg voltage : 12,6V)


Unfortunately I have no Hot air station available (yet) to reflow the IC ; the board looks fine in that area - no sign of liquid damage (and this PC has not be subject to liquid spillage as far as I know)
PS: are your referring to Louis Rossmann's videos ?

BAT_DRV looks low (~SRN/SRP) as I suppose PU1 disconnected the battery from the system, which is powered from the AC adapter (even though Windows says otherwise...), as B+ is at 19,3V. Hence no current is flowing in (from the charger) or out of (to the system) the battery - which happens to be what the Battery says on SMBUS.

Now when the AC adapter is disconnected (and system off) I have the following readings:
[11] BAT_DRV 17V
[12] SRN 11V
[13] SRP 11V
and 11V on either side of the PQ8 mosfet hence on B+

PR66 and PR67 read respectively 10,3 and 7 ohm which seems to match the schematic

I must admit I'm out of options at this stage.

[Nze123]

Re: ACER TimelineX 4830TG not charging

Hi fellow hackers

I am still stuck with my Acer TimelineX 4830TG not charging the battery
I tried with the original (old) battery ; pretty much the same situation
With AC adapter connected charging light remains off, whether system is on or off

Battery Data read from SMbus:
18:27:51.822 -> Manufacturer Name: SANYO
18:27:51.870 -> Device Name: AS11A3E
18:27:51.870 -> Chemistry LION
18:27:51.870 -> Design Capacity: 6000
18:27:51.870 -> Design Voltage: 11100
18:27:51.917 -> Manufacture Date (Y-M-D): 2011-7-28
18:27:51.917 -> Serial Number: 1076
18:27:51.917 -> Specification Info: 33
18:27:51.917 -> Cycle Count: 477
18:27:51.917 -> Voltage: 11.27
18:27:51.917 -> Full Charge Capacity: 4913
18:27:51.917 -> Remaining Capacity: 1061
18:27:51.964 -> Relative Charge(%): 22
18:27:51.964 -> Absolute Charge(%): 18
18:27:51.964 -> Minutes remaining for full charge: -1
18:27:51.964 -> Cell 1 Voltage: 3745
18:27:51.964 -> Cell 2 Voltage: 3762
18:27:52.012 -> Cell 3 Voltage: 3767
18:27:52.012 -> Cell 4 Voltage: 0
18:27:52.012 -> State of Health: 5911
18:27:52.012 -> Battery Mode (BIN): 0b0
18:27:52.012 -> Battery Status (HEX): 0x40C0
18:27:52.012 -> Charging Current: 0
18:27:52.057 -> Charging Voltage: 0
18:27:52.057 -> Temp: 19.85
18:27:52.057 -> Current (mA): 0

SMBus sniffing attached
still regular polling of the battery data by the host ; no trafic with the charging IC
battery mode ; status oscillates between xC0 and xC7

PU1 pin voltages are the same as with the new battery
PQ8 is off (BATDRV = Battery voltage) when AC adapter is connected ; B+ rail is at 19V
PQ8 is on (BATDRV = battery voltage + 6V) when AC adapter disconnected ; B+ rail is battery voltage


With the new battery when pressing SW6 (battery indicator), the blue led briefly turns on, then off (with or without AC adapter)
With the original battery when pressing SW6, the amber led briefly turns on, then off (with or without AC adapter)
[schematics p41]


So indeed the KBD is discussing with the battery, and the LED GPIO seem to work OK ; only for some reason the charging instructions are not sent to the PU1 charging IC slave on SMBus and the charging LED does not turn on (not sure what the KBD protocol is on this PC though)

Suspecting some issue with the BIOS, I removed the CMOS battery and let it sit for ~2h ; no change. Same with SW7 battery reset button does not help.

Any clue what is going on here, or guidance on what I should look for / try would be greatly appreciated

[mon2]

Re: ACER TimelineX 4830TG not charging

Consider to reflash the bios. Then check the SMBUS traffic again for possible detection of the battery address.

[Nze123]

Re: ACER TimelineX 4830TG not charging

I would surely love to, however the BIOS flash utility (InsydeFlash) fails on "AC detect error!", even though the PC is powered via the AC adapter and the B+ is 19V.
Any other way to flash the bios ?

Meanwhile Windows10 status bar shows "power mode : battery" ; battery remains at 40% charge however long the PC is powered ; so the PC is actually powered via AC adapter through the AC mosfets, and Battery is disconnected via PQ8

My guess is that the KBD probably tells the CPU that the AC is not present, and simultaneously does not trigger the charge IC via SMbus commands.
What could cause KBD fail to detect the AC power ?