17CBP4 — Cathode Ray Picture Tube

A rectangular glass, direct-view cathode ray tube featuring electrostatic focus and magnetic deflection, designed for television receiver applications.

Overview

The 17CBP4 is a direct-view cathode ray picture tube designed for television display systems. It features a rectangular glass construction, electrostatic focusing, and magnetic deflection. The tube is equipped with a unipotential cathode, an external conductive coating, a gray filter faceplate, and requires an external single-field ion trap.

The 17CBP4 is identical to the 17BUP4 picture tube in its electrical and mechanical specifications, with the sole distinction being that the 17CBP4 has a non-aluminized screen.

Construction and Optical Characteristics

The 17CBP4 is built with a rectangular glass envelope and utilizes magnetic deflection to sweep the electron beam across the screen. The approximate deflection angles are:

• Horizontal: 85°
• Vertical: 68°
• Diagonal: 90°

The screen has a minimum useful diagonal of 15 9/16 inches, a width of 14 5/16 inches, and a height of 11 1/8 inches, producing a standard raster size of 14 5/16" x 11 1/8".

The optical characteristics of the screen and faceplate include:

• Phosphor: P-4 (Sulfide type)
• Fluorescent Color: White
• Phosphorescent Color: White
• Persistence: Short
• Faceplate Transmission: Approximately 74% at the center
• Screen Type: Non-aluminized

An external conductive coating is applied to the bulb, which, in combination with the internal anode, forms a capacitor. The direct interelectrode capacitances are:

• Cathode to all other electrodes: Approximately 5 µµf
• Grid #1 to all other electrodes: Approximately 6 µµf
• External conductive coating to anode: Minimum 1200 µµf, Maximum 1500 µµf

Mechanical Specifications and Basing

The physical dimensions and mechanical features of the 17CBP4 are:

• Overall Length: 15 1/4 ± 3/8 inches
• Neck Diameter: 1 7/16 inches
• Greatest Bulb Dimensions:
  • Diagonal: 16 5/8 ± 1/8 inches
  • Width: 15 3/8 ± 1/8 inches
  • Height: 12 9/32 ± 1/8 inches
• Bulb Contact: Recessed small cavity cap (J1-21)
• Base: Small shell duodecal 6-pin (B6-63)
• Basing Arrangement: 12L
• Bulb Contact Alignment: The J1-21 contact aligns with pin position #6 ± 30 degrees.

The bottom view of the 12L basing arrangement provides the following pin connections:

• Pin 1: Heater
• Pin 2: Grid #1
• Pin 6: Grid #4
• Pin 10: Grid #2
• Pin 11: Cathode
• Pin 12: Heater
• Anode Cap: Grid No. 3, Grid No. 5, Anode

Electrical Characteristics and Typical Operating Conditions

The 17CBP4 operates with a nominal heater supply of:

• Heater Voltage: 6.3 V
• Heater Current: 0.6 A

Calculated Heater Power

The nominal heater power is calculated as: $\text{Heater Power} = 6.3\text{ V} \times 0.6\text{ A} = 3.78\text{ W}$ This calculation uses the nominal heater voltage and current as inputs.

Under typical operating conditions, the tube is set up with the following parameters:

• DC Anode Voltage: 12,000 V (Note: Brilliance and definition decrease below this value; operating voltage should not be less than 12,000 V)
• DC Grid #4 Voltage: -50 to +350 V
• DC Grid #2 Voltage: 300 V
• DC Grid #1 Voltage (for visual extinction of focused raster): -28 to -72 V
• DC Ion Trap Magnet Rated Strength: 32 Gausses (requires an external single field ion trap)

Maximum Ratings (Design Center System)

The maximum ratings are established under the Design Center System and must not be exceeded:

• Maximum DC Anode Voltage: 18,000 V
• Maximum DC Grid #4 Voltage: -500 to +1000 V
• Maximum DC Grid #2 Voltage: 500 V
• Maximum Grid #1 Voltage:
  • DC Negative-bias: 125 V
  • DC Positive-bias: 0 V
  • Positive-peak: 0 V
• Maximum DC Peak Heater-Cathode Voltage:
  • Heater negative with respect to cathode (during warm-up period ≤ 15 seconds): 410 V
  • Heater negative with respect to cathode (after equipment warm-up): 180 V
  • Heater positive with respect to cathode: 180 V
• Maximum Grid #1 Circuit Resistance: 1.5 MΩ

Technical Summary

The 17CBP4 is a rectangular glass, direct-view cathode ray picture tube featuring electrostatic focus and magnetic deflection. It is designed with a 90-degree diagonal deflection angle, a unipotential cathode, and a non-aluminized P-4 sulfide-type white phosphor screen. Operating at a nominal heater rating of 6.3 V and 0.6 A, the tube typically runs at an anode voltage of 12,000 V (with a design center maximum of 18,000 V) and requires an external single-field ion trap of 32 Gausses. It is identical to the 17BUP4 except for its non-aluminized screen construction.