Epson LQ-850 User Manual page 151

3. Holding the interface board level, rotate it clockwise into
position and attach it to the main board. Make sure that the
connector pins are properly inserted into the mating connector.
4. Secure the board with the screws provided.
5. Reassemble the printer, taking care not to pinch the FG wire
between the upper and lower sections of the case.
Interface Boards
7-33