Dell Precision 5520 Owner's Manual page 34

a. keyboard
b. system board
c. power connector port
d. display assembly
e. fans
f. heatsink assembly
g. speakers
h. WLAN card
i. hard drive(optional)
j. memory modules
k. battery
l. base cover
5. Follow the procedures in After Working Inside Your Computer
34 Disassembly and reassembly