IBM N51 Series, Hardware Maintenance Manual

Page: 94 / 503

Testing the Battery Pack
1. Place the computer bottom-side up.
2. Remove the battery pack and measure the voltage at
the battery terminals between 1 (
+
) and 3 (
−
).
1(+)
2(T)
3( )
Ÿ
If the voltage is less than
+
8.5 V dc, the battery
pack is discharged or defective.
Ÿ
If the voltage is more than
+
8.5 V dc, go to the
next step.
3. Using a low-power ohm meter, measure the
resistance at the battery terminals between
2 (T) and 3 (
−
). The resistance must be
4 kilohms to 30 kilohms. If the resistance is out of
range, replace the battery pack.
4. Remove the bottom cover and set the battery pack in
place without connecting any external power devices.
5. Measure the voltage at the connector between
terminals 1 (
+
) and 3 (
−
) on the voltage converter and
note the voltage.
1(+)
3( )
6. Using the AC adapter, apply external power to the
computer.
Warning: Be careful not to cause a short circuit
while doing the following steps. The charging circuit
is active even if the computer power switch is set to
off.
7. Measure the voltage again between terminals
1 (
+
) and 3 (
−
).
Ÿ
If the voltage is not greater than that measured
in Step 5, replace the AC adapter, then go to the
next step.
Ÿ
If the voltage is greater than that measured in
Step 5, the battery pack is good.
Pin Voltage (V dc)
1
+
8.5 to
+
18.0
2 Thermal Detection
3 Ground
82
IBM Mobile Systems HMM - Volume 1