Checking The Backup Battery - Lenovo 64576PU Hardware Maintenance Manual

Checkout guide
3. If the voltage is less than +11.0 V dc, the battery pack has been discharged.
4. If the voltage is more than +11.0 V dc, measure the resistance between battery

Checking the backup battery

Do the following:
1. Power off the computer, and unplug the ac adapter from it.
2. Turn the computer upside down.
3. Remove the battery pack (see "1010 Battery pack" on page 57).
4. Remove the backup battery (see "1100 Backup battery" on page 74).
5. Measure the voltage of the backup battery. See the following figure.
Red (+)
v If the voltage is correct, replace the system board.
v If the voltage is not correct, replace the backup battery.
v If the backup battery discharges quickly after replacement, replace the system
32
MT 8889, 8890, 8891, 8892, 8893, 8894, 8895, 8896, 8897, 8898, 8899, 8900, 8938, and 8939
7(-)
6(-)
5
4
3
1(+) 2(+)
Note: Recharging will take at least 3 hours, even if the indicator does not turn
on.
If the voltage is still less than +11.0 V dc after recharging, replace the battery.
terminals 5 and 7. The resistance must be 4 to 30 K .
If the resistance is not correct, replace the battery pack. If the resistance is
correct, replace the system board.
Black (-)
board.
Terminal Voltage (V dc)
1 + 0 to + 12.6
7 Ground (−)
Wire Voltage (V dc)
Red +2.5 to +3.2
Black Ground