Lenovo 28155XU, 28155YU, 2808DKU manual Checking the backup 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 83).

4.Remove the backup battery (see “1080 Backup battery” on page 100).

5.Measure the voltage of the backup battery. See the following figure.

Red (+)

Black (-)

Wire	Voltage (V dc)
Red	+2.5 to +3.2
Black	Ground

vIf the voltage is correct, replace the system board.

vIf the voltage is not correct, replace the backup battery.

vIf the backup battery discharges quickly after replacement, replace the system board.

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