Checking The Backup Battery - Lenovo ThinkPad X200 Tablet Hardware Maintenance Manual

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 "1020 Battery pack" on page 64).
4. Remove the backup battery (see "1090 Backup battery" on page 79).
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
board.
Black (-)
Wire Voltage (V dc)
Red +2.5 to +3.2
Black Ground
31
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