HP Compaq Presario CQ42-152TU Notebook PC - Manual (Page 73)

3. Plug the other end of the power cord into an AC outlet (3).
Testing an AC adapter
Test the AC adapter if the computer exhibits any of the following symptoms when it is connected to AC
power:
● The computer does not turn on.
● The display does not turn on.
● The power light is off.
To test the AC adapter:
1. Remove the battery from the computer.
2. Connect the AC adapter to the computer, and then plug it into an AC outlet.
3. Turn on the computer.
● If the power light turns on, the AC adapter is functioning properly.
● If the power light remains off, the AC adapter is not functioning and should be replaced.
Contact technical support for information on obtaining a replacement AC power adapter.
Select Start > Help and Support > Get assistance.
Using battery power
When a charged battery is in the computer and the computer is not plugged into external power, the
computer runs on battery power. When a charged battery is in the computer and the computer is plugged
into external AC power, the computer runs on AC power.
If the computer contains a charged battery and is running on external AC power supplied through the
AC adapter, the computer switches to battery power if the AC adapter is disconnected from the
computer.
NOTE: The display brightness is decreased to save battery life when you disconnect AC power. To
increase display brightness, press the f3 action key or reconnect the AC adapter.
Using battery power 63