IBM ThinkPad 2644, Hardware Maintenance Manual

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CHECKOUT GUIDE
3. If the voltage is less than
+
11.0 V dc, the battery pack
has been discharged. Recharge the battery pack.
Note
In this case, the battery pack is over-discharged.
It takes at least 3 hours to recharge the battery
pack even if the indicator does not turn on.
4. If the voltage is still less than
+
11.0 V dc after
recharging, replace the battery.
5. If the voltage is more than
+
11.0 V dc, measure the
resistance between battery terminals 3 and 4. The
resistance must be 4 K to 30 K ohm.
6. If the resistance is not correct, replace the battery
pack. If the resistance is correct, replace the system
board.
Checking the backup battery:
Do the following:
1. Power off the computer and unplug the AC Adapter
from the computer.
2. Turn the computer upside down.
3. Remove the backup battery (see “1020 Backup
battery” on page 56).
4. Measure the voltage of the backup battery. See the
following figure.
Ÿ
If the voltage is correct, replace the system board.
Ÿ
If the voltage is not correct, replace the backup
battery.
Terminal Voltage (V dc)
1
+
0 to
+
12.6
4 Ground (
−
)
Wire Voltage (V dc)
Red
+
2.5 to
+
3.2
Black Ground
Introduction
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