IBM ThinkPad 340 Series Hardware Maintenance Manual page 338

Pin
+
−
If the voltage is less than +4.0 V dc, replace the
DC/DC card. If the voltage is still low, replace
the system board.
If the voltage is more than +4.0 V dc, power-off
the computer, replace the standby battery, and
go to the next step.
7. Ensure that the AC Adapter is plugged into the
computer; then power-on the computer.
8. Charging of the standby battery starts. A depleted
battery needs approximately 30 minutes to be
recharged to the operational voltage of +3.5 V dc.
9. Unplug the AC Adapter.
10. Verify the standby battery function by removing and
installing the battery pack during suspend mode.
Note: Removing and installing the battery pack
during suspend mode should be done within one
minute. The resume operation must start. If the
resume operation does not work, switching of power
from the battery pack to standby battery will not be
correct. Replace the DC/DC card.
If replacing the DC/DC card does not resolve the
problem, replace the system board.
Power Management Features
Three power management modes are provided by the
computer to save power consumption and prolong battery
power.
328
IBM Mobile Systems HMM
Voltage (V dc)
+4.0
Ground