Epson 1010 User Manual page 165

If the FG wire is not attached, follow these steps:
1. Use the CG screw to attach the round end of the FG (frame
ground) wire to the main board and position the other end as
shown.
2. Carefully insert the pins on the optional interface board into the
mating connector on the main board; then secure the board with
the screws provided.
Using the Printer Options 5-41