Latitude 5420 Service Manual

Enter service mode

Service Mode allows you to immediately cut the power from the computer without disconnecting the battery cable or removing the battery from the computer.

1. Shut down the computer and disconnect the AC adapter from the computer.
2. Press and hold the <B> key on the keyboard, and then press the power button for 3 seconds until the Dell logo appears on the screen.

   

   The computer restarts and the following screed in displayed.

   

3. Press any key to continue.
   NOTE: The Service Mode procedure automatically skips this step if the Owner Tag of the system is not set up in advance by the manufacturer.
4. When the ready-to-proceed message appears on the screen, press any key to proceed. The system emits three short beeps and shuts down immediately.

   

   NOTE:If the AC adapter has not been disconnected, a message prompting you to remove the AC adapter appears on the screen. Remove the AC adapter and then press any key to continue the Service Mode procedure.

   

   Once the system shuts down, you can perform the replacement procedures without disconnecting the battery cable from the system board.

5. To exit Service Mode after finishing replacement procedures, connect AC adapter and press the power button to power on the system. The system automatically returns to normal functioning mode.