Checking the Backup Battery

1.Carefully place the computer bottom-side up.

2.Remove the bottom cover.

3.Disconnect the battery connector from the system board.

4.Measure the voltage of the backup battery. See the following figure.

(Red)

(Black)

Wire

Voltage

(V dc)

 

 

 

Red

+2.5

to+3.7

 

 

 

Black

Ground

 

 

 

 

Ÿ If the voltage is correct, replace the system board

ŸIf the voltage is not correct, the backup battery h been discharged by a short circuit or it is defect

Checking the

Standby

Battery

Note:

Make

sure

that the battery pack is removed

 

from

the computer before the standby battery

 

is

removed.

1.Power-off the computer and unplug the AC adapter cable from the computer.

2.Remove the battery pack.

3.Remove the indicator cover.

4.Disconnect the standby battery connector from the voltage converter.

5.Plug the AC adapter cable into the computer and power-on the computer.

6.Measure the output voltage at the connector on the voltage converter. See the following figure.

ThinkPad 700, 700C, 720, 720C (9552)75