Sony PCV-RX750 System Reference Manual page 41

!
Hold the add-in card by its edges and do not touch any components or
contacts on the card. Static electricity in your body may damage
sensitive components on the card. As a precaution, touch any exposed
metal part on the metal chassis (preferably the metal part on the power
supply) before handling an add-in card to discharge any static electricity
in your body.
5
If you do not replace the card or install another add-in card, install a
slot cover over the vacant slot at the rear of the chassis (see
an Open I/O Slot"
6
Replace the side panel (see
Upgrading and Maintaining Components
on page 38).
"Replacing the Side Panel"
27
"Covering
on page 25).