HP ProBook 4520s Maintenance And Service Manual page 102

4. Remove the ExpressCard bezel (1), then angle the top cover up (2), and lift it up (3) until it
disengages from the base enclosure.
Remove the top cover on 15.6-in computers:
1. Position the computer right-side up with the front toward you.
2. Disconnect the power button board cable from the system board by releasing the ZIF connector
(1), and then disconnecting the cable (2).
94 Chapter 4 Removal and replacement procedures