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The 1478K is a radar CRT and was listed as current but with an E suffix (probably phosphor colour) in the GEC 1976-77 short-form catalogue.
The final anode voltage of this magnetically deflected tube is designed to run at 17.5 kV and the EHT connector and cable is bonded in manufacture. The focus anode voltage is between -330 V and 0 V. The first anode runs at between -330 V to - 60 V. Cut-off is at a cathode voltage of 20. The face-plate is flat and the glass is thick. The base is given as B9A/D as the evacuation tube has to pass through the centre of the valve-holder.
The face-plate shows signs of phosphor burn in the shape of a semi-circle. Another example we have seen has a very pronounced semi-circular burn mark. The internal face of the bell is covered with aluminium. The catalogue dimensions for the screen are 132 x 80 mm.
The gun and focus anode. The bent pins suggest a less than gentle removal from its original equipment.
The EHT connector and part of the original anode lead. Such bonding may indicate that this tube was to be used in areas of high humidity - possibly air-borne.
The end window envelope is 23 mm in diameter, and excluding the B9A/D base pins is 255 mm tall.
References: GEC Catalogue.


Absolute Maximum Operating Conditions
Updated April 03, 2014.
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