Compaq Prolinea Family Maintenance & Serice Manual page 110

The following procedure assumes that a second hard drive is already
installed in the computer and it is being replaced. To install a second
hard drive with cable-select configuration, complete the following steps:
1. Complete the steps in Section 5.3 to prepare the computer for
disassembly.
2. Complete the steps in Unit Cover Removal and Replacement in Section 5.4
to gain access to the drive cage and hard drive.
3. Release the drive cage lock (plastic) on the top of the drive cage by
rotating it clockwise (Figure 5-12).
4. Elevating the drive cage will provide access to the drive cable
connectors. Push the metal drive cage release (Figure 5-13) away from
the drive cage and elevate the back end of the drive cage. The drive
cage release will engage a cutout in the side of the drive cage when
the drive cage has been elevated the proper amount (Figure 5-13).
5. Disconnect the power and signal cables from the back of the hard drive
as shown for a diskette drive in Figure 5-27. Hint: Use a rocking
motion on the signal cable connector (the largest connector) to ease
the removal of the connector.