12. Install the screw that secures the optical drive box on the VESA mount bracket.Figure167. Installing the screw that secures the optical drive box13. Connect the secondary hard disk drive cable to a USB connector on the computer. See “Locatingconnectors on the rear of your computer” on page 84.Installing or removing the I/O boxAttention:Do not open your computer or attempt any repair before reading and understanding the “Important safety information”on page 1.This section provides instructions on how to install or remove the I/O box.Note: The I/O box is only available on some models.The I/O box provides the following connectors for connecting to external devices:• Four USB 2.0 connectors (two on the front and two on the rear)• One serial port• Two PS/2 connectors (one for keyboard and one for mouse)To remove the I/O box, do the following:1. Remove all media from the drives and turn off all attached devices and the computer. Then, disconnectall power cords from electrical outlets and disconnect all cables that are connected to the computer.2. Disconnect the I/O box cable from the USB connector on the computer.208 ThinkCentre M73 Hardware Maintenance Manual
