Epson LQ-510 User Manual page 163

The Interface Boards
FG wire attached
1. Carefully place the interface board next to the printer as shown
below. Use the CG screw to connect the round end of the FG
(frame ground) wire to the main board.
2. Holding the interface board level, rotate it into position and
attach it to the main board. Make sure that the connector pins
are properly inserted into the mating connector.
Using the Printer Options
5-39