IBM ThinkPad 340 Series Hardware Maintenance Manual page 336

Checking the Car-Battery Adapter
Note: There are several types of adapters but the
checkout procedure is the same for both of them.
1. Unplug the Car-Battery Adapter cable from the
computer.
2. Plug the Car-Battery Adapter into the cigarette lighter
socket.
Note: If the adapter is already plugged in, reseat it.
3. Measure the output voltage of the Car-Battery
Adapter cable. See the following figure.
Pin
1
2, 3
If the voltage is correct and the power-on
indicator on the Car-Battery Adapter is on all the
time, the Car-Battery is working correctly.
Replace the system board.
If the problem is not resolved when the system
board is replaced, go to "Undetermined
Problems" on page 343.
If the voltage is outside the normal voltage
range, do one of the following:
–
–
Note: If the output voltage from the cigarette lighter
socket of the car is less than 10.5 V dc, a
continuous noise can be heard. The condition of
the car battery should be checked by appropriate
service personal.
Checking the Backup Battery
1. Power-off the computer and unplug the AC Adapter
from the computer.
2. Open the keyboard, and remove the battery pack.
3. Remove the backup battery from the shield assembly.
4. Measure the voltage of the backup battery. See the
following figure.
326
IBM Mobile Systems HMM
2
Try the above test procedures in a different
car, if one is available.
Replace the Car-Battery Adapter if the
computer works correctly with the AC
Adapter.
3
1
Voltage (V dc)
+19.0 to +21.0
Ground