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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.
Checking the Standby Battery: Be careful not
to cause a short circuit when measuring the voltage.
1. Power-off the computer and unplug the AC Adapter
from the computer.
2. Remove the standby battery.
3. Measure the voltage of the standby battery.
If the voltage between red and black is 3.5 V dc
or greater, the voltage is correct. Go to Step 9
on page 33 to verify standby battery operation.
If the voltage is less than 3.5 V dc, go to the
next step.
4. Plug the AC Adapter into the computer and power-on
the computer.
5. Measure the output voltage at the connector on the
system board.
Wire Voltage (V dc)
Red +2.9 to +3.3
Black Ground
32 IBM Mobile Systems HMM