chip needs to be closest to the center of the circuit board, not closest to the siderail. If you look closely at the white silkscreen lettering/lines on the circuitboard, you will also note that on one side there is a white 'half circle' which indicates where the notch on the EPROM needs to be oriented. Additionally, the socket will also have an indicator like a dimple, or that side is recessed to help one identify the correct orientation.