A63-11X

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Telefunken PALcolor 708T from 1967 with A63-11X

The A63-11X was the first delta shadow masks - color picture tube , which was developed in Germany in the mid-1960s, built and sold from the 1967th They came from the Telefunken and Valvo companies . It was built into the first-generation color television sets by almost all companies and is based on the American 25AXP22, which was one of the first rectangular color picture tubes to replace the American round-bottom tubes.

Technical specifications

The deflection angle is specified as 90 °, the anode voltage as 25 kilovolts (max. 27.5 kilovolts).

interpretation

The shadow mask of the A63-11X was designed for the American number of lines of 525 lines according to the NTSC method. When reproducing a television picture with 625 lines, as it is, for. B. is the norm for PAL -coded color television, the larger hole spacing on the mask resulted in undesirable moiré effects (streaking) on ​​the screen. This could be suppressed somewhat by reducing the image focus . The shadow masks of the later Permachrome picture tubes (A56-120X, A65-120X, A66-120X) were adapted to the 625 line standard according to PAL.

mechanics

Another shortcoming of the A63-11X was the suspension of the shadow mask. This warped when heated by the jet stream, which resulted in unpleasant errors in the color purity. The rule was that the setting of the color purity of the picture tube could only be made after approx. 15 minutes of operation with a medium screen brightness.

Arrangement of the electron guns

In contrast to today's color picture tubes, the three color electron guns are housed in the shape of a triangle in the neck of the picture tube. Hence the name delta picture tube , in contrast to the inline picture tubes , where they are in a row next to each other.

Long term properties

The A63-11X can tend to lose emissions after a long idle period of several decades. Then the beam currents of the cathodes fall to very low values ​​when first used after such a long time, and the picture tube shows predominantly weak values ​​during a test. After several hours of operation, however, it can regenerate itself and return to its previous beam current output. Therefore, if the values ​​are weak, you should wait with a regeneration , because this can under certain circumstances shorten the life of the tube considerably.

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