HP LaserJet PRO M521 Repair Manua page 113

3.
Release two tabs, and then carefully remove two wire connectors from the interlock switch
assembly.
TIP:
It might be easier to release these connectors by first removing the interlock switch. See
Interlock-switch assembly on page
Figure 1-150
Figure 1-151
ENWW
89.
Remove the DC controller (2 of 6)
Remove the DC controller (3 of 6)
Removal and replacement procedures
103