Dell OptiPlex 755 - Manual (Page 184)

Removing the Chassis Intrusion Switch
1. Follow the procedures in Before You Begin .
2. Remove the computer cover (see Removing the Computer Cover ).
3. Remove the hard drive (see Removing a Hard Drive ).
4. Disconnect the chassis intrusion switch cable from the system board by using two fingers to squeeze the release mechanism on one side of the
connector as you pull to disconnect the cable connector.
5. Slide the chassis intrusion switch out of its slot in the metal bracket, and then push it down through the square hole in the bracket to remove the switch
and its attached cable from the computer.
Replacing the Chassis Intrusion Switch
1. Gently insert the switch from underneath the metal bracket into the square hole in the bracket, and then slide the chassis intrusion switch into its slot
until it snaps securely into place.
2. Reconnect the cable to the system board.
3. Replace the hard drive (see Installing a Hard Drive ).
4. Replace the computer cover (see Replacing the Computer Cover ).
5. If you are using a computer stand, attach it to the computer.
Resetting the Chassis Intrusion Detector
1. Turn on (or restart) your computer.
2. When the blue DELL™ logo appears, press <F2> immediately.
If you wait too long and the operating system logo appears, continue to wait until you see the Microsoft® Windows® desktop. Then shut down your
computer and try again.
3. Select the Chassis Intrusion option and then press the left- or right-arrow key to select Reset. Change the setting to On, On-Silent, or Disabled.
4. Save your BIOS settings and exit system setup.
NOTE: You may feel a slight resistance as you slide the switch out of the slot.
NOTE: The default setting is On-Silent.