16YP4 — Cathode Ray Picture Tube

A direct-view, round glass picture tube designed for television receiver applications, featuring magnetic focus and deflection, a grey filter faceplate, and an external conductive coating.

Overview

The 16YP4 is a specialized direct-view cathode ray tube (CRT) designed for monochrome television display systems. It features a round glass envelope with a nominal outer diameter of 16 inches (specifically, a maximum bulb diameter of 15 7/8 inches) and is capable of displaying a standard 10 1/4" by 14 1/2" raster.

The tube utilizes magnetic deflection and magnetic focusing. To optimize picture contrast under ambient room lighting, the 16YP4 is equipped with a grey filter faceplate. It also incorporates an external conductive coating that, when grounded, forms a high-voltage filter capacitor in conjunction with the tube's internal conductive anode coating. Operation of the tube requires an external single-field ion trap magnet to prevent ion-burn damage to the phosphor screen.

Mechanical Specifications and Physical Dimensions

The mechanical design of the 16YP4 is tailored for standard television chassis mounting. The physical dimensions and alignment parameters are as follows:

• Overall Length: 17 5/16 ± 3/8 inches
• Greatest Diameter of Bulb: 15 7/8 ± 1/8 inches
• Minimum Useful Screen Diameter: 14 1/2 inches
• Neck Diameter: 1 7/16 ± 1/16 inches
• Bulb Contact: Recessed small cavity cap (J1-21)
• Base: Small shell duodecal 5-pin base (B5-57)
• Basing Designation: 12N
• Anode Terminal Alignment: The J1-21 recessed cavity cap aligns with pin position #3 within a tolerance of ±10 degrees.
• Ion Trap Magnet Clearance: A space of 3 7/8 ± 1/16 inches along the neck, measured from the reference line, must be kept clear for the installation and adjustment of the external single-field ion trap magnet.

Electrical and Optical Characteristics

The electrical and optical parameters of the 16YP4 define its performance as a display device.

Optical Data

• Phosphor Number: No. 4 (P4)
• Fluorescent Color: White
• Phosphorescent Color: White
• Persistence: Medium
• Faceplate Light Transmission: Approximately 70% at the center of the faceplate.

Direct Interelectrode Capacitances

• Cathode to all other electrodes: Approximately 5.0 µµF
• Grid No. 1 to all other electrodes: Approximately 6.0 µµF
• External conductive coating to anode:
  • Maximum: 2,000 µµF
  • Minimum: 750 µµF

Terminal Connections and Pinout

The 16YP4 uses a duodecal 5-pin base (B5-57) with the 12N basing arrangement. The electrical connections, viewed from the bottom of the tube base, are as follows:

Ratings and Operating Limits

The ratings for the 16YP4 are established under the Design Center system. Operating the tube beyond these limits may impair performance or shorten its service life.

Heater-Cathode Voltage Limits

To prevent insulation breakdown between the heater and the cathode, the peak voltage between these elements must not exceed the following limits:

• Heater negative with respect to cathode:
  • During equipment warm-up period (not to exceed 15 seconds): 410 V
  • After equipment warm-up period (steady state): 150 V
• Heater positive with respect to cathode: 150 V

Typical Operating Conditions

For typical television receiver operation, the 16YP4 is operated under the following conditions:

• DC Anode Voltage: 12,000 V
• DC Grid No. 2 Voltage: 300 V
• DC Grid No. 1 Voltage (for visual extinction of undeflected focused spot): -33 V to -77 V
• DC Focusing Coil Current: Approximately 100 mA

Focusing Coil Specifications

The typical focusing coil current of 100 mA is specified using a standard focus coil (such as the #109 or equivalent). This operating point is defined under the following conditions:

• The combined Grid No. 1 bias voltage and video signal voltage are adjusted to produce a highlight brightness of 30 foot-lamberts.
• The raster size is adjusted to 10 1/4" by 14 1/2".
• The distance from the reference line to the center of the air gap on the focus coil is exactly 3.25 inches.

Technical Summary

The 16YP4 is a 16-inch round glass, direct-view cathode ray tube designed for television receivers. It features a 70-degree magnetic deflection angle, magnetic focusing, and requires an external single-field ion trap magnet. Operating with a standard 6.3 V, 0.6 A heater, the tube is rated for a maximum DC anode voltage of 14,000 V and utilizes a P4 phosphor screen to produce a white-emitting display with medium persistence. The grey filter faceplate provides a light transmission of 70% to optimize contrast. Electrical connections are made via a small shell duodecal 5-pin base (B5-57) and a recessed small cavity cap (J1-21) for the high-voltage anode.