Abstract: Apparatus is used to restore the efficiency of depleted cathode-ray tubes for TV-sets, and to project the image of the cathode onto the screen of each tube, thus giving the possibility to check visually the condition of the cathode. The apparatus includes two feeders, series-connected with each other, the first of which is designed to generate a voltage up to 5000 V maximum, while the second is designed to generate a voltage up to 7000 V maximum. Both feeders are fitted with terminals, through which they can be separately connected with the electrodes of a cathode-ray tube.