19CHP4 — Rectangular Glass Television Picture Tube

The 19CHP4 is a 19-inch direct-view rectangular glass television picture tube designed primarily for cathode-drive service. It features a low-voltage electrostatic focusing system, 114-degree magnetic deflection, and an aluminized screen with a P4-sulfide type phosphor. The tube's design eliminates the need for an external ion-trap magnet, and it incorporates a controlled heater warm-up time for series-string or parallel heater applications.

Construction and Mechanical Characteristics

The 19CHP4 is constructed with a rectangular glass envelope and a spherical faceplate made of gray filterglass, which provides approximately 78% light transmission to enhance picture contrast under ambient light. The tube utilizes the J149A bulb and has a nominal neck diameter of 1-1/8 inches (1.125 inches, with a tolerance of +0.043 inches and -0.025 inches).

Key mechanical dimensions and physical characteristics include:

• Overall Length: 11-5/8 ± 1/4 inches
• Neck Length: 4-3/8 ± 1/8 inches
• Weight: Approximately 13.5 to 14 pounds
• Operating Position: Any
• Screen Dimensions (Minimum Useful):
  • Height: 12 inches
  • Width: 15-3/16 to 15-3/8 inches
  • Diagonal: 17-3/8 to 17-9/16 inches
  • Projected Area: 172 square inches

The tube is equipped with an external conductive coating (regular band) that must be grounded, with the contact area for grounding located near the reference line. The high-voltage connection is made via a recessed small cavity cap (JEDEC No. J1-21) located on the bulb cone. The base is a small-button Neoeightar 7-pin configuration (JEDEC No. B7-208) with an 8HR basing designation. Pin 4 of the base aligns with the horizontal centerline of the tube within 30 degrees on the same side as the anode contact.

Heater and Warm-Up Ratings

The 19CHP4 is designed with a heater that has a controlled warm-up time, making it suitable for use in television receivers with series-connected heater strings.

• Nominal Heater Voltage: 6.3 V
• Heater Current: 600 mA (with a tolerance of ±30 mA or ±5%)
• Average Heater Warm-Up Time: 11 seconds
• Heater Voltage Limits (Design-Maximum): 5.7 V minimum to 6.9 V maximum

Pinout and Basing Configuration

The 19CHP4 uses the 8HR bottom-view basing arrangement. The electrical connections are allocated as follows:

• Pin 1: Heater
• Pin 2: Grid No. 1
• Pin 3: Grid No. 2
• Pin 4: Grid No. 4 (Focusing Electrode)
• Pin 6: Grid No. 1
• Pin 7: Cathode
• Pin 8: Heater
• Anode Cap (Ultor): Grid No. 3, Grid No. 5, and Collector (Screen)
• C: External Conductive Coating (must be grounded)

Note that Grid No. 1 is connected to both Pin 2 and Pin 6.

Direct Interelectrode Capacitances

The direct interelectrode capacitances of the 19CHP4 are measured as approximate values:

• Grid No. 1 to all other electrodes: 6 pF
• Cathode to all other electrodes: 5 pF
• External conductive coating to anode (ultor): 1000 pF minimum to 1500 pF maximum

The capacitance of the external conductive coating to the anode serves as a high-voltage filter capacitor when the coating is properly grounded.

Design-Maximum Ratings

The following design-maximum ratings represent the absolute limits within which the 19CHP4 must be operated to ensure reliability and performance. All voltages are specified as positive with respect to Grid No. 1 unless otherwise noted.

Typical Operating Conditions (Cathode Drive Service)

Under typical operating conditions in cathode-drive service, the electrode voltages are set relative to Grid No. 1 as follows:

• Ultor-to-Grid-No. 1 Voltage: 16,000 Vdc
• Grid-No. 2-to-Grid-No. 1 Voltage: 50 Vdc
• Grid-No. 4-to-Grid-No. 1 Voltage for Focus: -50 to +250 Vdc (or 0 to 400 Vdc)
• Cathode-to-Grid-No. 1 Voltage for Visual Extinction of Focused Raster: 32 to 50 Vdc

For visual extinction of an undeflected focused spot, the absolute bias required increases by approximately 5 V relative to the raster extinction value.

Deflection and Scanning Angles

The 19CHP4 utilizes magnetic deflection to scan the electron beam across the screen. The deflection angles are:

• Diagonal Deflection: 114°
• Horizontal Deflection: 101°
• Vertical Deflection: 86°

Maximum Circuit Values

To maintain stable operation and prevent damage to the tube's electron gun, the maximum resistance in the Grid No. 1 circuit must be limited:

• Grid-No. 1-Circuit Resistance: 1.5 MΩ maximum

The external conductive coating must be securely grounded to the receiver chassis to complete the high-voltage return path and provide proper shielding.