Dell Latitude 120L (WISTRON DK1 MB) - no battery detected

[cruiser_]

Hello there!

I have a problem with and old laptop I got hold of.
It charges the battery and works off of it, but the battery itself is not detected in BIOS (no battery installed) or OS. It is a genuine DELL one.

The AC adapter is recognized as 60W.

The voltages on the battery connector (with AC on, no battery)
2 - 3.3 (PBAT_PRES)
4 - 3.3 (BT_SCL_R)
5 - 3.3 (BT_SDA_R)
6 - 15.8 (and goes down)

With AC adapter on + battery
2 - 0 (PBAT_PRES)
4 - 3.0 (BT_SCL_R)
5 - 3.0 (BT_SDA_R)
6 - 12.2 (and grows)

I am working on the diagram from
https://drive.google.com/file/d/1-DL...RbuZ9j1Kt/view

I checked R525, R526, R524, R189, R190
diodes D2/D3/D16
capacitors EC59, C270.

Still no joy :|

What else can I check guys?

[KvnTM]

Re: Dell Latitude 120L (WISTRON DK1 MB) - no battery detected

Take a look at the I2C Bus (SDA, SCL) with an oscilloscope if you have one.
I'd bet that battery is dead.

It is not detected but it still works off it? What does HWINFO say about it?

[diif]

Re: Dell Latitude 120L (WISTRON DK1 MB) - no battery detected

Have you checked BCC1 ?

[cruiser_]

Re: Dell Latitude 120L (WISTRON DK1 MB) - no battery detected

When is I2C comm supposed to happen? I looked with a mini osc at SDA & SCL while connecting the battery (no charger) - no activity. When should the BIOS talk to it?

The laptop is disassembled now so I cannot boot it to the OS, but from the Linux kernel message I remember acpi system reporting 'battery absent' during boot.

I couldn't find BCC1. No boardview here

But I do remember from the measurements, that between 'after' the R524/525/526 and GND there was steady 0.6kohm and capacity of 186nF with R524/525 and only 4nF with R526. Hope you know what I mean Can this rule out busted capacitor on these lines?

[cruiser_]

Re: Dell Latitude 120L (WISTRON DK1 MB) - no battery detected

With charger connected, there's loads of activity on SDA&SCL pins. Will yet have to hook up logic analyser to see what the messages sent are. Still scratching my head as to why BIOS would not see the battery...

[cruiser_]

Re: Dell Latitude 120L (WISTRON DK1 MB) - no battery detected

I hooked up the battery to my arduino and ran SBMInfo. It seems the battery operates fine on the logic level:

START D:\downloads\tmp\SBMInfo\SBMInfo.ino
Version 3.1 from Nov 22 2019
Found attached I2C device at 0xB

*** STATIC INFO ***
Chemistry: LION
Manufacturer Name: SMP-SDI2.6
Manufacturer Data: 4 20 20 20 20 7 20 20 20 20 20 20 20 1D 1 6 C FB 0 0 A 64 1 F4 10 9A 10 86
Device Name: DELL YD12068B
Serial Number: 1355
Manufacture Date (YYYY-MM-DD): 2006-8-11
Design Capacity: 5200 mAh
Design Voltage: 11.100 volt
Charging Current: 3500 mA
Charging Voltage: 12.975 volt
Specification Info: 33
Cycle Count: 136
Max Error of charge calculation (%): 100
RemainingTimeAlarm: 10 min
Remaining Capacity Alarm: 520 mAh
Battery Mode (BIN): 0b110000110000001
- Internal Charge Controller Supported
- Battery OK
- Charge Controller Enabled
- Disable AlarmWarning broadcast to Host and Smart Battery Charger
- Disable broadcasts of ChargingVoltage and ChargingCurrent to Smart Battery Charger
Pack Status (BIN): 0b1110001000100000

*** MANUFACTURER INFO ***
Device Type: 57888 / 0xE220

*** RATE TEST INFO ***
Setting AT rate to 100 mA
TimeToFull at rate: 38726 min
Setting AT rate to -100 mA
TimeToEmpty at rate: 570 min
Can be delivered for 10 seconds at rate: 1

*** DYNAMIC INFO ***
Full Charge Capacity: 65494 mAh
Remaining Capacity: 950 mAh
Relative Charge: 1 %
Absolute Charge(%): 18
Minutes remaining until empty: Battery not beeing (dis)charged
Average minutes remaining until empty: Battery not beeing (dis)charged
Minutes remaining for full charge: Battery not beeing (dis)charged
Battery Status (BIN): 0b11010111
- Initialized
- Discharging
- Fully Discharged
Voltage: 11.920 volt
Current: 0 mA
Average Current of last minute: 0 mA
Temperature: 21.45 C

*** DYNAMIC NON STANDARD INFO ***
Cell 1 Voltage: 3.970 volt
Cell 2 Voltage: 3.974 volt
Cell 3 Voltage: 3.978 volt
Cell 4 Voltage: 0.000 volt
State of Health: 0

*** CHANGED VALUES ***