19ATP4 — Tri-Potential Electrostatic Focus Television Picture Tube

The 19ATP4 is a 19-inch, direct-viewed, rectangular glass television picture tube designed for use in television receivers. It features a spherical faceplate with a bonded shield, tri-potential electrostatic focusing, magnetic deflection, and an aluminized screen. The tube does not require an ion trap and utilizes an external conductive coating that must be grounded.

Mechanical Specifications and Construction

The 19ATP4 is constructed with a rectangular glass bulb (C149 Exp. #5 or equivalent) and a laminated safety plate (FP159A). The faceplate is spherical and incorporates a bonded shield consisting of a gray filter glass safety plate laminated directly to the face of the tube. This configuration provides a light transmittance of approximately 44%.

The screen uses an aluminized P4 phosphor, which produces a white fluorescence with short-to-medium persistence.

Physical Dimensions and Weight

• Overall Length: 11-1/16 to 11-11/16 inches (with a tolerance of ± 5/16 inches)
• Neck Length: 3-9/16 ± 1/8 inches
• Minimum Useful Screen Dimensions:
  • Height: 12-1/16 inches
  • Width: 15-5/16 inches
  • Diagonal: 17-3/4 inches
  • Area: 174 square inches
• Weight: Approximately 18.5 lbs
• Bulb Contact: Recessed Small Cavity Cap (J1-21)
• Base: B7-208 (Basing 8JR)

Deflection and Focusing

The tube utilizes magnetic deflection with the following deflection angles:

• Diagonal: 114°
• Horizontal: 102°
• Vertical: 86°

Focusing is achieved via a tri-potential electrostatic method, which utilizes Grid No. 3 as the focusing electrode.

Heater and Electrical Characteristics

The 19ATP4 is equipped with an indirectly heated cathode. The heater has a controlled warm-up time designed for series or parallel heater string applications.

Heater Ratings

• Heater Voltage: 6.3 V
• Heater Current: 0.60 A ± 5%
• Heater Warm-up Time: 11 seconds

Direct Interelectrode Capacitances

• Cathode to All Other Electrodes: Approximately 5 µµF
• Grid No. 1 to All Other Electrodes: Approximately 6 µµF
• External Conductive Coating to Anode: 1000 µµF minimum to 1500 µµF maximum

The external conductive coating must be grounded to the receiver chassis to serve as a high-voltage filter capacitor in conjunction with the internal anode coating.

Basing and Pinout Configurations

The 19ATP4 uses a B7-208 base with an 8JR basing diagram. There are minor variations in the documented pin assignments for Pin 1 and Pin 2. In one configuration, Pin 1 is the heater and Pin 2 is Grid No. 1, while in another, Pin 1 is Grid No. 1 and Pin 2 is the heater. The remaining connections are identical across both configurations.

Pin Connections (8JR)

• Pin 1: Heater (H) or Grid No. 1 (G1)
• Pin 2: Grid No. 1 (G1) or Heater (H)
• Pin 3: Grid No. 2 (G2)
• Pin 4: Grid No. 3 (G3 / Focusing Electrode)
• Pin 6: Internal Connection (IC)
• Pin 7: Cathode (K)
• Pin 8: Heater (H)
• Cap: Anode (A)

Note on Alignment: Base Pin No. 4 aligns with the horizontal centerline of the tube within 30° and is positioned on the same side as the recessed small cavity cap anode contact.

Operating Conditions and Ratings

The operating limits and typical operating points for the 19ATP4 are specified under the Design-Maximum Rating System for grid-drive service.

Design-Maximum Ratings

• Anode Voltage: 12,000 V dc (Minimum) to 20,000 V dc (Maximum)
• Grid No. 3 Voltage (Focusing Electrode): 700 V dc (Maximum)
• Grid No. 2 Voltage: 600 V dc (Maximum)
• Grid No. 1 Voltage:
  • Negative Bias Value: 155 V dc (Maximum)
  • Negative Peak Value: 220 V (Maximum)
  • Positive Bias Value: 0 V dc (Maximum)
  • Positive Peak Value: 2 V (Maximum)
• Peak Heater-Cathode Voltage:
  • Heater Negative with Respect to Cathode (during warm-up ≤ 15 s): 450 V (Maximum)
  • Heater Negative with Respect to Cathode (after warm-up): 200 V (Maximum)
  • Heater Positive with Respect to Cathode: 200 V (Maximum)

Typical Operating Conditions (Grid Drive Service)

• Anode Voltage: 16,000 V dc
• Grid No. 3 Voltage for Focus: 0 to +400 V dc
• Grid No. 2 Voltage: 500 V dc
• Grid No. 1 Voltage Required for Cutoff: -43 to -78 V dc (for visual extinction of the focused raster; visual extinction of a stationary focused spot requires approximately 5 V more negative bias)

Maximum Circuit Values

• Grid No. 1 Circuit Resistance: 1.5 Megohms (Maximum)

Operating Safety Notes

When operating the 19ATP4, the external conductive coating must be securely grounded. Additionally, X-ray radiation shielding may be necessary if the tube is operated at anode voltages exceeding 16,000 V or the maximum rated anode voltage, whichever is less.

Technical Summary

The 19ATP4 is a 19-inch rectangular glass television picture tube featuring a 114° diagonal magnetic deflection angle and tri-potential electrostatic focusing. It is characterized by a spherical faceplate with a bonded gray filter glass safety plate (FP159A) providing 44% light transmittance, an aluminized P4 screen with white fluorescence, and a 6.3 V, 0.60 A heater with an 11-second warm-up time. Operating under grid-drive service, it supports anode voltages up to 20,000 V dc and requires proper grounding of its external conductive coating.