Epson 3865X Plus - Manual (Page 241)

3. Use one of your hands to hold up the subassembly at an
angle or have someone hold it up for you. With your other
hand, reach under the subassembly and grasp the two main
system board power supply cables. The cables are labeled
P4 and P5, and have opaque, white plastic connectors on
their ends. Each connector also has six pin holes and a large
tab on one side, as shown below.
large tabs
B-50
Installing and Removing Disk Drives