19DWP4 — Rectangular Glass Television Picture Tube

The 19DWP4 is a 19-inch direct-viewed rectangular glass television picture tube designed for use in television receivers. It features electrostatic focusing and magnetic deflection, utilizing an aluminized P4 phosphor screen that produces white fluorescence with medium-short persistence. The tube is constructed with integral implosion protection and does not require an external ion trap.

Mechanical Design and Physical Construction

The 19DWP4 is built using the J149F glass bulb envelope, featuring a spherical gray filter glass faceplate with an approximate light transmittance of 49%. The tube incorporates a banded integral implosion protection system consisting of a tension band and a rim band. To ensure proper operation and safety, the external conductive coating and the rimbands must be grounded.

Physical Dimensions and Weight

• Overall Length: 11 3/8 ± 1/4 inches
• Neck Length: 4 1/8 to 4 1/4 inches (with a tolerance of ± 1/8 inch)
• Neck Diameter: 1 1/8 inches
• Weight: Approximately 15 lbs
• Bulb Contact: Recessed small cavity cap (J1-21)
• Base: B7-208 (8HR basing configuration)

Screen Characteristics

• Minimum Useful Screen Dimensions: 12 inches Height x 15 3/8 to 15 3/4 inches Width x 17 9/16 inches Diagonal
• Minimum Useful Screen Area: 172 square inches
• Phosphor: Aluminized P4 (white fluorescence, medium-short persistence)

Electrical Characteristics and Basing

The 19DWP4 features an indirectly heated cathode. The heater is designed to operate under specified warm-up conditions to ensure reliability in series-string receiver designs.

Heater Ratings

• Heater Voltage: 6.3 V
• Heater Current: 0.45 ± 5% A
• Heater Warm-up Time: 11 seconds

The heater warm-up time is defined as the time required for the heater voltage to reach 80% of its rated value when four times the rated heater voltage is applied in series with an external resistance equal to three times the rated heater voltage divided by the rated current.

Pinout and Terminal Connections

The tube utilizes an 8-pin B7-208 base with an 8HR basing arrangement. The pin connections, viewed from the bottom of the base, are as follows:

The recessed small cavity cap (J1-21) is located on the same side of the envelope as Pin 4 and aligns with the horizontal centerline of the tube within a tolerance of 30°.

Interelectrode Capacitances and Resistance

• Cathode to all other electrodes: 5 pF (approximate)
• Grid No. 1 to all other electrodes: 6 pF (approximate)
• External conductive coating and rimbands to anode: 1000 pF minimum, 1500 pF maximum
• Resistance between external conductive coating and metal bands: 50 Megohms minimum

Operating Modes and Maximum Ratings

The 19DWP4 can be operated in either Grid Drive Service or Cathode Drive Service. The maximum ratings are defined under the Design-Maximum rating system.

Grid Drive Service

In Grid Drive Service, electrode voltages are specified with respect to the cathode.

• Anode Voltage: 11,000 Vdc minimum to 23,000 Vdc maximum
• Grid No. 4 (Focusing Electrode) Voltage: -550 Vdc to +1100 Vdc
• Grid No. 2 Voltage: 200 Vdc minimum to 550 Vdc maximum
• Grid No. 1 Voltage:
  • Negative bias value: 154 Vdc maximum
  • Negative peak value: 220 V maximum
  • Positive bias value: 0 Vdc maximum
  • Positive peak value: 2 V maximum

Typical Operating Conditions (Grid Drive)

• Anode Voltage: 20,000 Vdc
• Grid No. 4 Voltage for Focus: -200 to +200 Vdc
• Grid No. 2 Voltage: 400 Vdc
• Grid No. 1 Voltage for Cutoff: -50 to -98 Vdc (for visual extinction of a focused raster; the absolute value increases by approximately 5 V for an undeflected focused spot)

Cathode Drive Service

In Cathode Drive Service, electrode voltages are specified with respect to Grid No. 1.

• Anode Voltage: 11,000 Vdc minimum to 23,000 Vdc maximum
• Grid No. 4 (Focusing Electrode) Voltage: -400 Vdc to +1250 Vdc
• Grid No. 2 Voltage: 350 Vdc minimum to 700 Vdc maximum
• Cathode Voltage:
  • Positive bias value: 154 Vdc maximum
  • Positive peak value: 220 V maximum
  • Negative bias value: 0 Vdc maximum
  • Negative peak value: 2 V maximum

Typical Operating Conditions (Cathode Drive)

• Anode Voltage: 20,000 Vdc
• Grid No. 4 Voltage for Focus: -200 to +200 Vdc
• Grid No. 2 Voltage: 400 Vdc
• Cathode Voltage for Cutoff: 48 to 82 Vdc (for visual extinction of a focused raster; the absolute value increases by approximately 5 V for an undeflected focused spot)

Heater-Cathode Voltage Limits (Both Services)

• Heater Negative with Respect to Cathode:
  • During the equipment warm-up period (not to exceed 15 seconds): 450 V maximum
  • After the equipment warm-up period: 300 V maximum
• Heater Positive with Respect to Cathode:
  • Total value: 200 V maximum
  • DC component: 100 V maximum

Circuit Constraints and Safety Considerations

Circuit Values

The maximum allowable resistance in the Grid No. 1 circuit is 1.5 Megohms.

X-ray Radiation Warning

When operating the 19DWP4, safety precautions regarding X-ray radiation must be observed. If the tube is operated at anode voltages higher than 16,000 volts or the maximum rated anode voltage (whichever is less), shielding may be necessary to protect personnel against prolonged exposure at close range.