19DBP4 — Rectangular Cathode Ray Tube

The 19DBP4 is a 19-inch direct-view rectangular picture tube designed for television display applications. It features a spherical faceplate made of gray filter glass, an aluminized screen, and a bonded protective implosion panel. The tube utilizes electrostatic focusing and a $114^\circ$ magnetic deflection angle. It is specifically designed for cathode-drive service, operating with a low Grid #2 voltage of 40 V, and does not require an external ion trap.

Physical and Optical Characteristics

The 19DBP4 is constructed using a J149C1 glass bulb and an FP149B2 bonded implosion panel. The faceplate is made of gray filter glass with an approximate light transmittance of 48% at the center, which enhances picture contrast under bright ambient lighting conditions. The screen is coated with a P4 aluminized phosphor, providing high brightness and efficient light output.

Mechanical Dimensions

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

Minimum Useful Screen Dimensions (Projected)

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

Deflection Angles

The magnetic deflection system operates with the following approximate angles:

• Diagonal: $114^\circ$
• Horizontal: $103^\circ$
• Vertical: $86^\circ$

Electrical Connections and Pinout

The tube utilizes a B6-214 base with a 7FA basing arrangement. The high-voltage anode connection is made via a recessed small cavity contact (J1-21). The anode contact is aligned with the pin position #7 within a tolerance of $\pm 30^\circ$.

The pin assignments for the 7FA base, viewed from the bottom, are:

Direct Interelectrode Capacitances

• Cathode to all other electrodes: 5 $\mu\mu\text{f}$ (approximate)
• Grid #1 to all other electrodes: 6 $\mu\mu\text{f}$ (approximate)
• External conductive coating to Anode:
  • Maximum: 1900 $\mu\mu\text{f}$
  • Minimum: 1400 $\mu\mu\text{f}$

The external conductive coating, when connected to a system ground, forms a high-voltage filter capacitor with the internal anode coating.

Heater and Filament Ratings

The heater is designed for a nominal voltage of 6.3 V. The electrical specifications for the filament are:

• Nominal Heater Voltage: 6.3 V
• Heater Current: $450 \pm 10%$ mA (at 6.3 V)
• Heater Warm-up Time: 11 seconds

Maximum Ratings (Design Maximum System)

All voltages are positive and measured with respect to Grid #1 unless otherwise specified. Under the Design Maximum System, the operating limits are:

• Anode Voltage: 19,800 V maximum, 12,000 V minimum
• Grid #4 (Focusing Electrode) Voltage: +1100 V maximum, -500 V minimum
• Grid #2 Voltage: 60 V maximum, 25 V minimum
• Cathode Voltage: 100 V maximum
• Heater Voltage: 7.0 V maximum, 5.8 V minimum
• Heater-Cathode Voltage:
  • Heater negative with respect to cathode during warm-up ($\le 15$ seconds): -410 V maximum
  • Heater negative with respect to cathode after warm-up: -180 V maximum
  • Heater positive with respect to cathode: 180 V maximum
• Grid #1 Circuit Resistance: 1.5 Megohms maximum

Typical Operating Conditions (Cathode Drive Service)

In typical cathode-drive applications, the electrodes are operated under the following conditions (with voltages measured with respect to Grid #1):

• Anode Voltage: 16,000 V
• Grid #2 Voltage: 40 V
• Grid #4 (Focusing Electrode) Voltage: 250 V
  • Note: Satisfactory focus is typically obtained on individual tubes at some value between 0 and 500 V when the combined Grid #1 bias and video-signal are adjusted for a $150\ \mu\text{A}$ anode current on a $15\ 1/8 \times 12$ inch pattern.
• Cathode Voltage: 35 to 50 V (for visual extinction of the focused raster)

Special Characteristics

The tube has a maximum anode penetration current of $150\ \mu\text{A}$. This is measured under specific test conditions: 19,800 V applied to the anode, 0 V applied to the cathode, Grid #1, and Grid #2, with all other elements set to their nominal voltages.

Technical Summary

The 19DBP4 is a highly integrated 19-inch rectangular cathode ray tube featuring a $114^\circ$ magnetic deflection angle and electrostatic focus. Its design is optimized for cathode-drive television receivers, utilizing a low Grid #2 voltage of 40 V and eliminating the need for an ion trap. With its built-in FP149B2 bonded implosion panel, gray filter glass faceplate, and aluminized P4 phosphor screen, the 19DBP4 provides a robust, high-contrast display solution. Its standard 7FA basing and 6.3 V heater make it compatible with contemporary television chassis designs of its era.