Lenovo 418734U - IdeaPad S9e 4187 Hardware Maintenance Manual page 39

4. Remove the backup battery (see "1110 Fan, backup battery, and system board"
on page 77).
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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