16BYP4 — 16-Inch Rectangular Cathode Ray Tube

The 16BYP4 is a 16-inch rectangular glass picture tube designed for television display applications. It features electrostatic focusing, magnetic deflection, and a spherical gray faceplate. The tube is characterized by its wide-angle deflection capabilities, a non-ion-trap electron gun, an aluminized screen, and a compact neck design.

Design and Construction

The 16BYP4 is constructed with a rectangular glass envelope (bulb designation J125-B1) and incorporates a banded-type implosion protection system. The fluorescent screen uses a P4 aluminized phosphor, which is designed to enhance light output and minimize undesirable screen charging. The faceplate is made of spherical gray glass with a light transmittance of approximately 54 percent at the center.

To reduce sweep-induced radiation and provide filtering, the tube is equipped with an external conductive coating. When grounded, this coating acts as a filter capacitor in conjunction with the anode. The electron gun is a non-ion-trap design, and the tube features a small neck diameter to facilitate compact deflection yoke designs.

Mechanical Specifications

The physical dimensions and mounting requirements of the 16BYP4 are highly specified to ensure proper alignment and safety:

• Overall Length: 10 7/16 ± 1/4 inches
• Neck Length: 4 1/4 ± 1/8 inches
• Greatest Dimensions:
  • Diagonal: 15.688 ± 0.100 inches
  • Width: 13.780 ± 0.100 inches
  • Height: 11.187 ± 0.100 inches
• Minimum Useful Screen Dimensions (Projected):
  • Diagonal: 14 7/8 inches
  • Horizontal Axis: 12 15/16 inches
  • Vertical Axis: 10 1/4 inches
  • Total Area: 125 square inches

The tube utilizes a JEDEC No. B7-208 base and an 8 HR basing configuration. The anode terminal is a JEDEC No. J1-21 bulb contact, which aligns with Pin No. 4 of the base within a tolerance of ±30 degrees. The reference line of the tube is established by the intersection of the plane C-C of an EIA No. 126 gage with the glass funnel. For installation, a non-rigidly mounted socket with flexible leads must be used, and the bottom circumference of the base wafer must fall within a 1-3/4 inch diameter circle concentric with the bulb axis.

Electrical and Deflection Characteristics

The 16BYP4 operates with a combination of electrostatic focusing and magnetic deflection. The deflection angles are:

• Diagonal (Approximate): 114 degrees
• Horizontal (Approximate): 102 degrees
• Vertical (Approximate): 84 degrees

Heater Ratings

The heater is designed for a nominal operating voltage of 6.3 volts and draws a current of 450 ± 23 mA. The heater warm-up time is approximately 11 seconds.

Interelectrode Capacitances

• Cathode to all other electrodes: 0.5 µµF (approximate)
• Grid No. 1 to all other electrodes: 0.6 µµF (approximate)
• External conductive coating to anode: 1000 µµF minimum / 1500 µµF maximum

Basing Diagram and Pin Connections

The 16BYP4 uses the 8 HR basing arrangement. The pin connections, viewed from the bottom of the base, are as follows:

• Pin 1: Heater
• Pin 2: Grid No. 1
• Pin 3: Grid No. 2
• Pin 4: Focusing Electrode (Grid No. 4)
• Pin 6: Grid No. 1
• Pin 7: Cathode
• Pin 8: Heater
• Bulb Contact: Anode (JEDEC No. J1-21)

Design Maximum Ratings

The following ratings are established under the Design Maximum System. All voltage values are positive and measured with respect to the cathode unless otherwise specified:

• Anode Voltage: 10,000 V minimum to 16,000 V maximum
• Grid No. 4 (Focusing Electrode) Voltage: -500 V to +1000 V
• Grid No. 2 Voltage: 75 V minimum to 200 V maximum
• Grid No. 1 Voltage:
  • Maximum Negative DC Value: 140 V
  • Maximum Negative Peak Value: 200 V
  • Maximum Positive DC Value: 0 V
  • Maximum Positive Peak Value: 2 V
• Heater Voltage: 5.7 V minimum to 6.9 V maximum
• Maximum Heater-Cathode Voltage:
  • Heater negative with respect to cathode:
    • During warm-up period (not to exceed 15 seconds): 410 V
    • After equipment warm-up period: 180 V
  • Heater positive with respect to cathode: 180 V

Typical Operating Conditions

For typical cathode drive service, the operating parameters are defined as follows:

• Anode Voltage: 13,000 V DC
• Grid No. 4 (Focusing Electrode) Voltage: 0 V DC
• Grid No. 2 Voltage: 100 V DC
• Cathode-to-Grid No. 1 Voltage: 31 V to 49 V DC (for visual extinction of a focused raster)

The 0-volt focus condition is specified with the combined Grid No. 1 bias voltage and video-signal voltage adjusted to produce an anode current of 150 microamperes on a 12 15/16 x 10 1/4 inch pattern (such as that from an RCA 2F21 monoscope or equivalent).

Maximum Circuit Values and Protection

To prevent damage to the tube's electrodes, the following circuit resistance limits must be maintained:

• Maximum Grid No. 1 Circuit Resistance: 1.5 megohms
• Minimum Grid No. 2 Circuit Resistance: 0.1 megohm
• Minimum Focusing Electrode Circuit Resistance: 0.1 megohm

The installation of protective resistance in the Grid No. 2 and focusing electrical circuits is highly advisable to prevent damage to the tube. If applicable, a single resistor common to both circuits may be utilized.

Technical Summary

The 16BYP4 is a specialized 16-inch rectangular glass cathode ray tube designed for television display systems. It combines a wide 114-degree diagonal magnetic deflection angle with electrostatic focusing, allowing for a compact overall length of 10 7/16 inches. Its design features a P4 aluminized screen, a spherical gray faceplate with 54% light transmittance, and a 450 mA heater with an 11-second warm-up time. Operating under the Design Maximum System, it supports anode voltages up to 16,000 V and utilizes an 8 HR basing configuration. Proper circuit design requires adhering to specified minimum and maximum resistance values on Grid No. 2 and the focusing electrode to ensure long-term reliability.