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4. If the voltage is more than +11.0 V dc, measure the
resistance between battery terminals 3 and 4. The
resistance must be 4 to 30 K ohm.
If the resistance is not correct, replace the battery
pack. If the resistance is correct, replace the system
board.
Checking the Backup Battery
1. Power off the computer and unplug the AC Adapter
from the computer.
2. Turn the computer upside down.
3. Remove the DIMM cover and backup battery (see
“1010 Backup Battery” on page 298).
4. Measure the voltage of the backup battery. See the
following figure.
Note: Be careful not to measure the wrong side of
the backup battery.
Black (-)
Red (+)
S
O
N
Y
+
If the voltage is correct, replace the system board.
If the voltage is not correct, the backup battery has
been discharged. Replace the backup battery.
If the backup battery discharges quickly after
replacement, replace the system board.
Wire Voltage (V dc)
Red +2.5 to +3.7
Black Ground
Port Replicator Checkout
Use the following procedure to isolate a port replicator
problem. A port replicator attaches to the system
expansion connector at the bottom of the computer.
1. Power off the computer.
2. Remove the failing devices from the replicator.
3. Unplug the AC adapter from the replicator, if
attached.
4. Remove the port replicator from the computer.
ThinkPad 560 (2640)
275