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 shut-down instructions.
3. Disconnect your computer and all attached devices from their electrical outlets.
4. Disconnect all attached network devices and peripherals, such as keyboard, mouse, and monitor from your computer.
5. Remove any media card and optical disk from your computer, if applicable.
6. Enter the service mode, if you are able to power on your computer.

   Service Mode

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

   CAUTION:If you are unable to turn on the computer to put it into Service Mode, or the computer does not support 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 AC adapter is disconnected.
   1. Hold <B> key on the keyboard and press the power button for 3 seconds or until the Dell logo appears on the screen.
   2. Press any key to continue.
   3. If the AC adapter is not 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 process. 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.
   5. Once the computer shuts down, it has successfully entered Service Mode.
   NOTE:If you are unable to power on your computer or unable to enter Service Mode, skip this process.