Lenovo T400s User Manual - Page 61

Checking the backup battery - power adapter

Page 61 highlights

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 Red Black Voltage (V dc) +2.5 to +3.2 Ground 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. General checkout 53

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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
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.
General checkout
53