19DZP4 — Electrostatic-Focus Picture Tube

A 19-inch rectangular glass cathode-ray tube featuring magnetic deflection, an aluminized P4 phosphor screen, and a short-neck, non-ion trap gun designed for cathode drive service.

Overview

The 19DZP4 is a rectangular, glass, aluminized picture tube designed for television display applications. It features a 19-inch diagonal screen, electrostatic focusing, and magnetic deflection. The tube incorporates a short-neck, non-ion trap electron gun designed specifically for cathode drive operation. Its spherical gray faceplate provides approximately 78% light transmittance at the center, which helps maintain high picture contrast under ambient lighting conditions. The tube is also equipped with an external conductive coating that, in conjunction with the internal anode coating, forms a high-voltage filter capacitor.

Physical and Mechanical Design

The 19DZP4 utilizes a J149A1A glass bulb. The physical dimensions of the tube are compact, featuring a short neck length of 4 1/2 ± 1/8 inches, which contributes to a shallow cabinet depth.

Overall Dimensions

• Overall Length: 11 3/4 ± 1/4 inches
• Greatest Diagonal: 18 5/8 ± 1/8 inches
• Greatest Width: 16 13/32 ± 1/8 inches
• Greatest Height: 13 11/32 ± 1/8 inches

Screen and Display Area

The screen is rectangular with a spherical gray faceplate. The minimum useful projected screen dimensions are:

• Diagonal: 17 9/16 inches
• Horizontal Axis: 15 1/8 inches
• Vertical Axis: 12 inches
• Total Useful Area: 172 square inches

Deflection Angles (Approximate)

• Diagonal: 114 degrees
• Horizontal: 102 degrees
• Vertical: 87 degrees

Base and Electrical Connections

The tube uses a JETEC No. B7-237 or B7-208 base with an 8HR basing arrangement. The high-voltage anode connection is made via a JETEC No. J1-21 bulb contact located on the long side of the bulb. This anode contact aligns with Pin No. 4 within a tolerance of ± 30 degrees.

The pinout configuration (8HR basing) viewed from the bottom of the base is as follows:

• Pin 1: Heater (H)
• Pin 2: Grid No. 1 (G1)
• Pin 3: Grid No. 2 (G2)
• Pin 4: Focus / Grid No. 4 (F)
• Pin 6: Grid No. 1 (G1)
• Pin 7: Cathode (K)
• Pin 8: Heater (H)
• Bulb Contact: Anode (A)

Electrical Characteristics and Heater Ratings

The 19DZP4 is designed with a low-power heater and specific interelectrode capacitances to ensure stable operation in television receivers.

Heater Ratings

The heater is designed for a nominal voltage of 6.3 V and has a controlled warm-up time.

• Heater Voltage: 6.3 V (with design-maximum limits of 5.7 V minimum to 6.9 V maximum)
• Heater Current: 450 ± 23 mA
• Heater Warm-up Time: 11 seconds

Direct Interelectrode Capacitances

• Cathode to all other electrodes: approximately 0.5 µµF
• Grid No. 1 to all other electrodes: approximately 0.6 µµF
• External conductive coating to Anode: 1000 µµF minimum to 1500 µµF maximum

The external conductive coating, when connected to the chassis, forms a high-voltage filter capacitor with the internal anode coating, which helps smooth the high-voltage anode supply.

Operating Conditions and Ratings

The 19DZP4 is rated under the Design-Maximum System. All voltage values are positive and measured with respect to the cathode unless otherwise specified.

Absolute Design-Maximum Ratings

• Anode Voltage: 10,000 V minimum to 18,000 V maximum
• Grid No. 4 (Focusing Electrode) Voltage: -500 V to +1000 V
• Grid No. 2 Voltage: 100 V minimum to 250 V maximum
• Grid No. 1 Voltage:
  • Maximum Negative DC Value: 140 V
  • Maximum Negative Peak Value: 200 V
  • Maximum Positive DC Value: 0 V
  • Maximum Positive Peak Value: 2 V
• Maximum Heater-Cathode Voltage:
  • Heater negative with respect to cathode during warm-up (≤ 15 seconds): 410 V
  • Heater negative with respect to cathode after equipment warm-up: 180 V
  • Heater positive with respect to cathode: 180 V

Typical Operating Conditions (Cathode Drive Service)

In typical cathode drive service, the input signal is applied to the cathode, and the operating voltages are established as follows:

• Anode Voltage: 13,000 V DC
• Grid No. 4 Voltage: -250 V to +150 V DC (adjusted for optimum focus at 150 µA anode current on a 15 1/8 x 11 15/16 inch pattern)
• Grid No. 2 Voltage: 150 V DC
• Cathode to Grid No. 1 Voltage: 36 V to 54 V DC (required for visual extinction of the focused raster)

Maximum Circuit Values

To prevent damage to the tube's internal electrodes from transient arcs or discharges, specific circuit resistance limits must be observed:

• Maximum Grid No. 1 Circuit Resistance: 1.5 MΩ
• Minimum Grid No. 2 Circuit Resistance: 0.1 MΩ
• Minimum Focusing Electrode Circuit Resistance: 0.1 MΩ

Note: It is advisable to include protective resistance in the Grid No. 2 and focusing electrode circuits to safeguard the tube.

Technical Summary

The 19DZP4 is an electrostatic-focus, magnetic-deflection glass picture tube featuring a 114-degree diagonal deflection angle, a short neck, and a non-ion trap gun optimized for cathode drive service. Operating with a 6.3 V, 450 mA heater, it provides a 172-square-inch display area on an aluminized P4 phosphor screen. Under typical cathode drive conditions, it operates with an anode voltage of 13,000 V, a Grid No. 2 voltage of 150 V, and a focusing voltage range of -250 V to +150 V. Circuit designs must incorporate protective resistances in the Grid No. 2 and focusing electrode paths to ensure long-term reliability.