19EGP4 — Electrostatic-Focus Magnetic-Deflection Television Picture Tube

The 19EGP4 is a 19-inch cathode ray tube (CRT) designed for television receiver applications. It features a 114-degree magnetic deflection angle, a straight electron gun requiring no ion-trap magnet, and low-voltage electrostatic focusing. The tube incorporates a filled-rim type implosion protection system with integrated hardware, a spherical gray filter glass faceplate, and an aluminized P4 phosphor screen.

Mechanical and Optical Specifications

The 19EGP4 is constructed using a JEDEC J149F (or J149F1) glass bulb envelope. It features a recessed small cavity cap (JEDEC J1-21) for the high-voltage anode connection and a small-button Neoeightar 7-pin base (JEDEC B7-208). The anode cap is aligned with pin position number 4 within a tolerance of ±30 degrees.

Physical Dimensions

• Overall Length: 11.625 ± 0.250 inches
• Neck Length: 4.375 ± 0.125 inches
• Neck Diameter: Maximum of 1.168 inches at the splice
• Greatest Shell Dimensions:
  • Diagonal: 20.875 ± 0.094 inches (or 20 7/8 ± 3/32 inches)
  • Width: 17.125 ± 0.063 inches (or 17 1/8 ± 1/16 inches)
  • Height: 14.078 ± 0.063 inches (or 14 5/64 ± 1/16 inches)
• Minimum Useful Screen Dimensions (Projected):
  • Diagonal: 17.562 inches (or 17 9/16 inches)
  • Horizontal Axis: 15.125 inches (or 15 1/8 inches)
  • Vertical Axis: 12.000 inches
  • Projected Area: 172 square inches
• Net Weight: Approximately 16 to 16.25 pounds

Optical Characteristics

The faceplate is made of gray filter glass with a light transmittance of approximately 48% to 49% at the center. It does not feature an anti-reflection treatment. The screen utilizes an aluminized, sulfide-type P4 phosphor, which provides a white display.

Heater and Basing Configuration

The 19EGP4 is equipped with an indirectly heated cathode. The heater is designed for series or parallel operation in television receivers.

Heater Ratings

• Nominal Heater Voltage: 6.3 V
• Design-Maximum Heater Voltage Range: 5.7 V or 5.8 V to 6.9 V
• Heater Current: 450 mA with a tolerance of ±5% (or ±20 mA)
• Heater Warm-up Time: 11 seconds (average). This warm-up characteristic is defined as the time required for the heater to reach 80% of its rated voltage when four times the rated voltage is applied in series with a resistance equal to three times the rated voltage divided by the rated current.

Basing and Pin Connections

The tube utilizes the JEDEC 8HR basing arrangement. Under this configuration, the pin connections viewed from the bottom of the base are:

Grid No. 1 is internally connected to both Pin 2 and Pin 6. The external conductive coating is of the modified-band type, providing a contact area for grounding near the reference line.

Electrical Characteristics and Capacitances

The direct interelectrode capacitances of the 19EGP4 are relatively low, minimizing loading on the driving circuitry:

• Cathode to all other electrodes: Approximately 5 pF
• Grid No. 1 to all other electrodes: Approximately 6 pF
• External conductive coating to anode: 1,000 pF minimum to 1,500 pF maximum (or up to 1,250 pF minimum to 1,750 pF maximum depending on the specific implosion-protection hardware configuration).

The electrical resistance between the external conductive coating and the implosion-protection hardware is specified as a minimum of 5 Megohms or 50 Megohms, depending on the hardware grounding arrangement.

Design-Maximum Ratings

The following limits are established under the Design-Maximum System. All voltages are positive and measured with respect to Grid No. 1 unless otherwise specified.

Electrode Voltages

• Anode Voltage: 12,000 V minimum to 21,000 V maximum
• Grid No. 4 (Focusing Electrode) Voltage:
  • Maximum Positive Value: +1,000 V, +1,100 V, or +1,250 V
  • Maximum Negative Value: -400 V, -500 V, or -550 V
• Grid No. 2 Voltage: 20 V or 25 V minimum to 60 V maximum
• Cathode Voltage:
  • Maximum Negative Bias Value: 0 V DC
  • Maximum Negative Peak Value: 2 V
  • Maximum Positive Bias Value: 100 V or 154 V DC
  • Maximum Positive Peak Value: 150 V or 220 V

Heater-Cathode Voltage Limits

• Heater Negative with Respect to Cathode:
  • During equipment warm-up period (not to exceed 15 seconds): 450 V maximum
  • After equipment warm-up period: 200 V or 300 V maximum
• Heater Positive with Respect to Cathode:
  • Combined AC and DC voltage: 200 V maximum
  • DC component limit: 100 V maximum

Circuit Impedance Limits

• Maximum Grid No. 1 Circuit Resistance: 1.5 Megohms
• Minimum Grid No. 2 and Grid No. 4 Circuit Resistance: 10,000 Ohms. A protective resistance of at least this value is advised in these electrode circuits to prevent damage from internal arcing.

Typical Operating Conditions (Cathode-Drive Service)

In typical cathode-drive operation, the input signal is applied to the cathode while Grid No. 1 is held at a reference potential (usually ground). All voltages are positive and measured with respect to Grid No. 1.

• Anode Voltage: 16,000 V DC. Operating the tube at anode voltages exceeding 16,000 V may generate X-rays, which can require appropriate shielding in the receiver design.
• Grid No. 4 (Focusing Electrode) Voltage: Typically 250 V DC. Individual tubes are designed to focus satisfactorily within a range of 0 to +400 V DC (measured with an anode current of 150 µA on a 12" x 15.125" raster pattern).
• Grid No. 2 Voltage: 50 V DC
• Cathode Voltage for Raster Cutoff: 32 V to 50 V DC, or 35 V to 55 V DC, for visual extinction of the focused raster.
• Centering Magnet Field Strength: An adjustable centering magnet providing a field strength of 0 to 8 Gauss is required to align the raster.