Abstract: An image pickup tube is rigidly centered and mounted to a coil assembly by an adjustable split-ring clamp of hard plastic material mounted to the coil assembly. The split-ring clamp when adjusted for mounting compresses about the periphery of the faceplate or anti-halation disk extension of the tube to thereby provide a rigid mounting between the coil assembly and the tube. The rear portion of the coil assembly includes a yoke with a tapered inner surface. A split-ring wedge is forced between the tube and the rear portion of the yoke to rigidly support and center the rear portion of the tube.