Checking The Coin-Cell Battery - ThinkPad Edge E440 Hardware Maintenance Manual

Note: If the battery pack becomes hot, it may not be able to charge. Remove it from the computer and leave
it at room temperature for a while. After it cools down, reinstall and recharge it.
To check the battery pack, do the following:
1. Power off the computer.
2. Remove the battery pack and measure the voltage between battery terminals 1 (+) and 7 (-). See the
following figure:
3. If the voltage is less than +11.0 V dc, the battery pack has been discharged.
If the voltage is still less than +11.0 V dc after recharging, replace the battery pack.
4. If the voltage is more than +11.0 V dc, measure the resistance between battery terminals 5 and 7.
The resistance must be 4 to 30 K Ω. If the resistance is not correct, replace the battery pack. If the
resistance is correct, replace the system board.

Checking the coin-cell battery

Do the following:
1. Power off the computer, and unplug the ac power adapter from it.
2. Turn the computer upside down.
3. Remove the battery pack (see "1020 Battery pack" on page 65).
4. Remove the cion-cell battery (see "1100 Coin-cell battery" on page 74).
5. Measure the voltage of the coin-cell battery. See the following figure.
• 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
Terminal Voltage (V dc)
1, 2 + 0 to + 12.6
6, 7 Ground (-)
Wire Voltage (V dc)
Red +2.5 to +3.2
Black Ground