Checking The Coin-Cell Battery - Lenovo ThinkPad S540 Hardware Maintenance Manual

2. Connect the computer to ac power to charge the battery. If the battery status icon in the Windows
notification area indicates that the battery is not charging, remove the battery and let it return to room
temperature.
3. Reinstall the battery. If the battery is still not charging, replace the battery pack.
4. Check the battery status icon again. If the same error still exists, replace the system board.

Checking the coin-cell battery

To check the coin-cell battery, do the following:
1. Disable the built-in battery. See "Disabling the built-in battery" on page 60.
2. Remove the coin-cell battery. See "1090 Coin-cell battery" on page 71.
3. Measure the voltage of the coin-cell battery. See the following illustration.
• If the voltage is correct, replace the system board.
• If the voltage is not correct, replace the coin-cell battery.
• If the coin-cell battery discharges quickly after replacement, replace the system board.
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Hardware Maintenance Manual
Wire
Voltage (V dc)
Red +2.5 to +3.2
Black Ground