IL43234A - Apparatus for the regeneration of tv cathode-ray tubes - Google Patents

Abstract

1427250 Cathode-ray tubes SAFE ELECTRONIC SYSTEMS SA 15 Aug 1973 [25 Sept 1972] 39566/73 Heading H1D [Also in Division H4] An assembly for the rejuvenation of cathoderay display tubes and for the visual check of cathode conditions comprises first and second voltage converters S1, S2, the former, S1, having input terminals A, B connected to the primary of a mains transformer for, e.g. 220 V A.C. operations and the latter, S2, input lines 1, 2 connected either to the primary of the transformer in converter S1 or, alternatively, to a voltage source in the range 220 to 6000 V. Each converter has a plurality of output terminals to which controlled voltages may be supplied and converter S2 is additionally connected via further input lines 3, 4, to output terminals C and D of converter S1. In operation, when it is required to rejuvenate the tube, terminal C is connected to the tube cathode terminal D is connected to the first grid and terminals E and F are connected to the heater. An A.C. voltage in the range 6 to 12 V is then applied to terminals E and F and the heater is overheated for a period between a few seconds and a few minutes. A voltage in the range 50 to 5000 V is then applied to terminal D for a period ranging between one minute down to a quarter of a second (depending on the magnitude of the applied voltage) and the tube is thus rejuvenated. When the tube is a threegun colour tube each gun may be treated as described above or the converter S1 may be fitted with three separate sets of terminals. When a visual check on the cathode condition is required (even after it has been rejuvenated) terminals E1, F1 are connected to the heater, terminal C is connected to the cathode, terminal H, to which a voltage of between 0-50 V is supplied, is connected to the first grid, terminal L to which a voltage of between 150 and 400 V is supplied, is connected to the first anode, terminal M to which a voltage of between 100 and 300 V is supplied is connected to the second anode (focusing anode) and terminal AT, to which a voltage of between 4000 and 7000 V is supplied, is connected to the main anode. By manually varying the above voltages within the ranges indicated a disc-shaped image of the cathode is produced on the screen and if such image is luminous and uniform the efficiency of the tube is considered to be very good. If the image is speckled, the tube should be subjected to one or two rejuvenation cycles as described above. The various voltages produced by the converters S1, S2 may be either direct, alternating or pulsating and the converters are provided with either manual or automatic control devices controlling the magnitude and durations of the voltages applied to the tube. [GB1427250A]

Claims (4)

1. An assembly for the regeneration of cathode-ray tubes for TV-sets and fo the visual check of cathode conditions , comprising a first feeder and a second feeder series-connected with each other, wherein said first feeder can be directly connected with the mains system, and Is fitted with a set of at least four terminals, o which the first one is grounded, said feeder being designed to apply a direct, or alternating, or pulsating Voltage in the range from ab. 50 V up to ab. 5000 V to said second terminal,, and to apply a similar voltage in the range of ab. 6 and ab. 12 V between said third and fourth terminals, while the second feeder is directly connected with said first and second terminals of said first feeder, and can be simultaneously connected with another voltage source , there being provided at least one set of seven terminals , of which the irst and second ones are directly connected with the third and fourth terminals of said first feeder, said second feede being designed to appl a direct, or alternating or pulsating voltage in the range from ab. 0 V down to ab. -50 V to the said fourth terminal of said set of seven terminals, a similar voltage in the range from ab. 150: V up to ab. 400 to the fifth terminal of said set of seven terminals , a similar voltage in the range from ab. 1000 V up to 3000 V to the sixth terminal of said set of seven terminals, and in the range from ab. 400 V to ab. 7000 to the seventh terminal of said set of seven terminals, whil the third terminal of said set of seven terminals is grounded.

2. An assembly according to Claim 1, wherein said first feeder comprises manually or automatically operated devices, by which the time trough which a voltage is applied to feeder terminals can be accurately controlled.

3. An assembly according to Claims 1 or 2, wherein said second feeder is fitted with manually operated devices for varying, within the stated ranges, the voltage which is applied to terminals of samd feeder.

4. An assembly according to Claims 1 to 3 inclusive, wherein said other voltage source, with which said second feeder is connected, consists of transformer of first feeder. SC :CB