Epson 4500 - Manual (Page 180)

The Interface Boards
WARNING:
High voltages are present inside the printer when
the power is on. Do not attempt to remove the upper case
unless the printer is turned off and the power cord is
unplugged. Also, try not to touch contacts on the circuit
board of the printer because many of the components can be
destroyed by the static electricity present in your body.
Do not change the settings of any DIP switches on the main
board.
2. Remove the paper guide.
3. Remove the screw securing the interface board cover.
5-42 Using the Printer Options