Measurement Results:
| Pin # | Function | Expected Voltage (AC Plugged In) |
|---|---|---|
| 1 & 2 | Positive (+) | ~0V to 3V (May pulse; full 12V only after handshake) | 0.12-0.14V
| 3 | Thermistor (T) | ~0V (Monitoring pin) | 0V
| 4 | Clock (SCL) | 3.3V (Steady standby voltage) | 3.29V
| 5 | Data (SDA) | 3.3V (Steady standby voltage) | 3.29V
| 6 | System Present (P) | 3.3V (Battery pulls this to 0V when inserted) | 3.29V
| 7 & 8 | Ground (GND) | 0V (Continuity to laptop chassis) | 0V
Conclusion: Motherboard Ok; Bad batteries.
