HP EliteBook 820 G1 Notebook PC - Manual (Page 47)

To test the AC adapter:
1. Shut down the computer.
2. Remove the battery from the computer.
3. Connect the AC adapter to the computer, and then plug it into an AC outlet.
4. Turn on the computer.
● If the power lights turn on, the AC adapter is functioning properly.
● If the power lights remain off, the AC adapter is not functioning and should be replaced.
Contact support for information on obtaining a replacement AC power adapter.
Using external AC power 37