Dell Precision 490 - Manual (Page 51)

About the Metal Shields Present in Some Drive Configurations
In certain computer configurations, metal shields are present in the drive bays of your computer. If metal shields are present in your computer configuration,
they are essential and must be installed in the appropriate bays at all times.
Note the three scenarios in which a metal shield may be removed and not immediately replaced:
l If the FlexBay held a third hard-drive (in the tower configuration only) or was empty (in either configuration) with a vented metal shield in front of
it and you install a floppy drive or Media Card Reader in that bay, a shield is not needed in that bay.
l If the FlexBay held a Media Card Reader or floppy drive (in the tower configuration only) and you install a hard drive in its place, a vented metal
shield must be installed in front of the hard drive in the FlexBay.
l If a metal shield is installed in the 5.25-inch drive bay and you install an optical drive in its place, a shield is not needed in that bay.
In either of the above situations, the metal shield should be kept in case it is needed later.
If you remove a floppy drive, a Media Card Reader, or an optical drive from your computer, you will need to install a metal shield in its place. If a metal shield is
not installed in any of these cases, your computer may not function properly. Contact Dell if you need an extra shield (see
Contacting Dell ).
1 upper 5.25-inch drive bay (holds CD/DVD drive)
2 lower 5.25-inch drive bay (holds optional CD/DVD drive or SATA hard drive)
3 rotatable hard-drive carrier (holds two SAS or SATA drives)
4 FlexBay (holds optional floppy drive or Media Card Reader)
NOTICE: If metal shields are present in your computer configuration, they must be installed at all times while your computer is in use or your computer
may not function properly.
1 5.25-inch metal shield
2 vented metal insert