Epson EQUITY 386/33 PLUS - Manual (Page 47)

Removing the Subassembly
You need to remove the subassembly to install or remove disk
drives, or to access the SIMM or math coprocessor sockets on
your computer’s main system board. The subassembly is the
large metal casing that holds the horizontal drive bays and the
power supply, as shown below.
Accessing Internal Components 3-5