An apparatus is used to inspect an assembled circuit board having a device assembled to the circuit board by a ball grid array (BGA). The BGA includes a plurality of rows of solder connections. The apparatus has a source of light, which may be a laser. A first deflector is positioned to direct the light into a first side of the BGA, between two adjacent rows of solder connections in the BGA. A second deflector directs any light emitted from a second side of the BGA opposite the first side onto a target. The deflectors may be prisms, mirrors, or optical fibers. The target may be a viewing surface (such as a wall or screen) or a light detector, such as a camera, frame grabber, or photoelectric device. The absence of light on the target while the light is directed into the first side of the BGA indicates the presence of a solder bridge in the BGA. The light source, deflectors and detector may be moved at a constant rate along the length of the BGA, to provide a pattern of alternating light and dark illumination levels. The presence of a solder bridge may be detected based on the pattern.