Abstract: An apparatus for properly aligning a cathode-ray tube projection unit before a viewing screen includes a pair of ultrasonic rangefinders and a cooperating pair of light emitting diode (LED) reader units. One ultrasonic rangefinder and one reader unit are connected to each of two opposite sides of the projection unit. Each rangefinder is directed toward the viewing screen to sense the distance between the viewing screen and the side of the projection unit to which the rangefinder is connected. The cooperating LED reader unit then indicates whether that side is too close to, too far away from or a proper operating distance from the viewing screen.