Lenovo ThinkPad L412 Hardware Maintenance Manual page 61

4. Remove the backup battery (see "1130 Backup battery" on page 103).
5. Measure the voltage of the backup battery. See the following figure.
Red (+)
Black (-)
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
board.
Wire Voltage (V dc)
Red +2.5 to +3.2
Black Ground
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