Virtual Valve Museum

Virtual Valve Museum

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Size This CRT measures 180x44mm overall, and 35mm across the screen. It has a 9 pin base.


Heater voltage 4.0V
Heater current 1.0A
Max anode 4 voltage 4.0kV
Max anode 3 voltage 1.7kV
Max anode 2 voltage 200V
Max peak cathode current 500µA
Typical operating conditions
Anode 4 voltage 3.5kV
Anode 3 voltage 1.5kV
Anode 2 voltage 75V approx
Beam current 30µA
Cathode current 40µA
X plate sensitivity 0.110 mm/V
Y plate sensitivity 0.087 mm/V


Pin Function
1 Heater and cathode
2 Grid
3 Heater
4 Anode 2
5 X plate 1
6 Y plate 1
7 Anode 1 and anode 3
8 Y plate 2
9 X plate 2
Side contact Anode 4

When viewing the screen with the tube positioned such that the keyway of the spigot is at an angle of 30 degrees to the left of vertical, a positive voltage on X plate 1 (pin 5) will deflect the spot to the right, and a positive voltage on Y plate 2 (pin 8) will deflect it upwards.

Top quarter view Bottom quarter view
Below: two developmental versions, serials 1725 and 1737. The first has 4976 stamped inside, and the second has 5057.
Developmental tubes