Compaq 159715-002 - Deskpro EN - DT 6650 Model 10000 Configuration Manual page 19

7. Before you install each drive into the chassis, turn it so that
it is perpendicular to the internal 3.5-inch drive. The
bottom of the drive should be parallel to drivelock 2.
The diskette drive should always be placed in the bay
nearest the top of the chassis in the desktop configuration
for proper drive clearance and access.
Installing a Drive in the Desktop Configuration
8. Gently slide the drive into the bay. When the drive is
properly inserted, the drivelock will secure it.
CAUTION:
The use of unnecessary force may result in damage to
the drives.
9. Reconnect all power and data cables to the drives in the
5.25-inch drive bays.
Making Hardware Changes 2-9