Epson 486SX - Manual (Page 97)

3. Open the clasp holding the power supply and drive cables to
the side of the subassembly, as shown below. Then remove
all the cables from the clasp.
4. Grasp the back of the subassembly by the edge on its upper
left side, as shown below, and lift up the back end.
5. Pull the subassembly forward slightly to release it from the
two pins beneath the front panel opening. Then lift it out of
the computer and place it on your work surface.
Accessing Internal Components 5-7