Acer Network Device Altos R520 - Manual (Page 54)

3 System upgrade 44
To install the top cover:
1 Observe the ESD precautions and pre-installation instructions
described on page 39.
2 Place the top cover on the chassis so that the tabs on the cover
align with the slots on the chassis .
3 Slide the top cover toward the front of the chassis until it is fully
closed (A).
4 Replace the screw on the top cover (B).