Latitude 5540 Owner's Manual

Before working inside your computer

1. Save and close all open files and exit all open applications.
2. Shut down your computer. For Windows operating system, click Start > Power > Shut down.
   NOTE:If you are using a different operating system, see the documentation of your operating system for instructions.
3. Turn off all the attached peripherals.
4. Disconnect your computer from the electrical outlets.
5. Disconnect all attached network devices and peripherals, such as keyboard, mouse, and monitor from your computer.
6. Remove any media card and optical drive from your computer, if applicable.
7. Enter the Service Mode.

   Service Mode

   Service Mode is used to cut off power without disconnecting the battery cable from the system board before conducting repairs in the computer.

   CAUTION:If you are unable to turn on the computer to put it into Service Mode, proceed to disconnect the battery cable. To disconnect the battery cable, follow the steps in Removing the battery.

   NOTE:Ensure that your computer is shut down and the power adapter is disconnected.
   1. Press and hold the B key and the power button for 3 seconds or until the Dell logo appears on the screen.
   2. Press any key to continue.
   3. If the power adapter is not disconnected, a message prompting you to disconnect the power adapter appears on the screen. Disconnect the power adapter and then press any key to enter into the Service Mode. The Service Mode process automatically skips the following step if the Owner Tag of the computer is not set up in advance by the user.
   4. When the ready-to-proceed message appears on the screen, press any key to proceed. The computer emits three short beeps and shuts down immediately.
      The computer shuts down and enters the Service Mode.