19BCP4 — Rectangular Glass Television Picture Tube

The 19BCP4 is a 19-inch direct-viewed, rectangular glass television picture tube designed for television receiver applications. It features a spherical faceplate, a bonded shield, gray filter glass, and an aluminized screen. The tube incorporates electrostatic focusing and a 114-degree magnetic deflection system. It operates without an ion trap and includes an external conductive coating. The external surface of its safety plate is treated to reduce specular reflection, and the faceplate assembly provides a light transmittance of approximately 44%.

Mechanical Specifications and Physical Dimensions

The 19BCP4 is constructed using a J1-21 bulb and an FP159B safety plate. It has a recessed small cavity cap (J1-21) for the anode bulb contact and a B7-208 base. The physical dimensions and weight of the tube are as follows:

• Overall Length: 11 5/8 ± 3/16 inches
• Neck Length: 4 1/8 ± 1/8 inches
• Weight: Approximately 18.5 pounds
• Minimum Useful Screen Dimensions:
  • Height: 12 1/16 inches
  • Width: 15 1/4 inches
  • Diagonal: 17 1/4 inches
  • Area: 174 square inches

Electrical Characteristics and Heater Ratings

The 19BCP4 features an indirectly heated cathode with a controlled warm-up time.

• Heater Voltage: 6.3 Volts
• Heater Current: 0.30 Ampere ± 5%
• Heater Warm-up Time: 11 seconds

Direct Interelectrode Capacitances

The interelectrode capacitances of the tube are approximately:

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

Deflection, Focusing, and Phosphor Characteristics

The tube utilizes electrostatic focusing and magnetic deflection. The deflection angles are:

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

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

Basing and Pinout Connection

The 19BCP4 uses the 8HR basing configuration (B7-208 base). The pin connections, viewed from the bottom of the base, are:

• 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 Contact: Recessed Small Cavity Cap (J1-21)

Base Pin No. 4 aligns with the horizontal centerline (A-A') within 30% and is located on the same side of the neck as the anode contact.

Operating Conditions and Drive Services

The 19BCP4 can be operated in either Grid Drive Service or Cathode Drive Service. The typical operating conditions and maximum ratings (Design Maximum Values) differ between these two modes.

Grid Drive Service

In Grid Drive Service, the control signal is applied to Grid No. 1.

• Typical Operating Conditions:
  • Anode Voltage: 16,000 Volts DC
  • Grid No. 4 Voltage (Focus): 0 to 400 Volts DC
  • Grid No. 2 Voltage: 400 Volts DC
  • Grid No. 1 Voltage for Cutoff: -46 to -94 Volts DC
• Design Maximum Ratings:
  • Anode Voltage: 20,000 Volts DC
  • Grid No. 4 Voltage: -550 to +1100 Volts DC
  • Grid No. 2 Voltage: 550 Volts DC
  • Grid No. 1 Negative Bias: 155 Volts DC
  • Grid No. 1 Negative Peak: 220 Volts
  • Grid No. 1 Positive Bias: 0 Volts DC
  • Grid No. 1 Positive Peak: 2 Volts

Cathode Drive Service

In Cathode Drive Service, the control signal is applied to the cathode.

• Typical Operating Conditions:
  • Anode Voltage: 16,000 Volts DC
  • Grid No. 4 Voltage (Focus): 0 to 400 Volts DC
  • Grid No. 2 Voltage: 400 Volts DC
  • Cathode Voltage for Cutoff: 42 to 78 Volts DC
• Design Maximum Ratings:
  • Anode Voltage: 20,000 Volts DC
  • Grid No. 4 Voltage: -400 to +1250 Volts DC
  • Grid No. 2 Voltage: 700 Volts DC
  • Cathode Positive Bias: 155 Volts DC
  • Cathode Positive Peak: 220 Volts
  • Cathode Negative Bias: 0 Volts DC
  • Cathode Negative Peak: 2 Volts

Heater-Cathode Voltage Ratings

The heater-cathode voltage limits are identical for both Grid Drive and Cathode Drive services:

• Heater negative with respect to cathode (during warm-up ≤ 15s): 450 Volts peak maximum
• Heater negative with respect to cathode (after warm-up): 200 Volts peak maximum
• Heater positive with respect to cathode: 200 Volts peak maximum

Circuit Values and Operating Considerations

• Grid No. 1 Circuit Resistance: The maximum allowable resistance in the Grid No. 1 circuit is 1.5 Megohms.
• External Conductive Coating: The external conductive coating must be grounded to provide proper shielding and capacitance.
• Cutoff Voltage Definition: The specified cutoff voltage values are for the visual extinction of a focused raster. For the cutoff of an undeflected focused spot, the absolute value of the bias voltage between the cathode and Grid No. 1 increases by approximately 5 Volts.
• X-ray Warning: If the tube is operated at voltages higher than 16,000 Volts or the maximum rated anode voltage (whichever is less), shielding may be necessary to protect against prolonged exposure to X-radiation at close range.