A tracking mount assembly is provided for use with an electronic typewriter magnetic card support platform having a top surface and a card guide surface thereon. The tracking mount assembly includes a bridge frame with a lead screw and a guide shaft mounted in the frame. A pair of lugs extend from the frame and are formed with alignment surfaces thereon. The alignment surfaces of the lugs engage the card guide surface of the card support platform to align thelead screw and guide shaft relative to the card guide surface. The lead screw and guide shaft are further aligned relative to the plane of the top surface of the card support platform by the connection between the bridge frame and the card support platform.