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Specialized - Cathode Ray ·CathodeRay

16RP4

Direct-view cathode-ray picture tube documented by manufacturer data for type 16RP4; available extracted technical detail is limited, so the description remains conservative.

Directly heatedCold cathodeCommon cathodeDissimilarSpecialized
Sections
1
Base
12N
Socket code
DUODECAL5
Base pins
5
Nominal heater
6.3 V / 600 mA

Description

16RP4 — Rectangular Cathode Ray Picture Tube

The 16RP4 and 16RP4A are direct-view, rectangular glass cathode ray picture tubes designed for television receiver applications. These tubes feature magnetic focusing and magnetic deflection, a grey filter faceplate, a unipotential cathode, and require an external single-field ion trap. The two designations are identical in construction and electrical ratings, with the sole exception that the 16RP4A incorporates an aluminized screen for enhanced brightness, whereas the standard 16RP4 does not.

The tubes provide a nominal raster size of 10 1/8" by 13 1/2", housed in a rectangular glass envelope that minimizes space requirements compared to contemporary round designs.

Mechanical Specifications and Physical Dimensions

The 16RP4 and 16RP4A utilize a rectangular glass bulb construction with a nominal diagonal dimension of 16 inches. The physical dimensions and tolerances are specified as follows:

  • Overall Length: 18 3/4 ± 3/8 inches
  • Greatest Bulb Diagonal: 16 1/8 ± 1/8 inches
  • Greatest Bulb Width: 14 3/4 ± 1/8 inches
  • Greatest Bulb Height: 11 1/2 ± 1/8 inches
  • Minimum Useful Screen Diagonal: 14 7/8 inches
  • Minimum Useful Screen Width: 13 1/2 inches
  • Minimum Useful Screen Height: 10 1/8 inches

Base, Basing, and Connections

The tube is equipped with a Small Shell Duodecal 5-pin base (designation B5-57) and uses the 12N basing configuration. High-voltage anode connection is made via a recessed small cavity cap (designation J1-21). The alignment of this bulb contact is designed to align with pin position #6 within a tolerance of ±30 degrees.

The pin connections, viewed from the bottom of the base, are:

  • Pin 1: Heater
  • Pin 2: Grid No. 1
  • Pin 10: Grid No. 2
  • Pin 11: Cathode
  • Pin 12: Heater
  • Anode Cap: Anode

Electrical and Optical Characteristics

The electron gun structure consists of an indirectly heated unipotential cathode, a control grid (Grid No. 1), and a screen grid (Grid No. 2). The focusing and deflection systems are entirely magnetic.

Optical Data

The screen utilizes Phosphor No. 4, which is characterized by:

  • Fluorescent Color: White
  • Phosphorescent Color: White
  • Persistence: Medium
  • Faceplate Light Transmission: Approximately 66% at the center of the grey filter faceplate.

Deflection and Capacitance

The deflection angles are approximately:

  • Horizontal Deflection Angle: 65 degrees
  • Diagonal Deflection Angle: 70 degrees

Direct interelectrode capacitances are:

  • Cathode to all other electrodes: 5 µµF (pF)
  • Grid No. 1 to all other electrodes: 6 µµF (pF)
  • External conductive coating to anode (Maximum): 1,500 µµF (pF)
  • External conductive coating to anode (Minimum): 750 µµF (pF)

The external conductive coating acts as a capacitor in conjunction with the internal anode coating, providing filtering for the high-voltage anode power supply.

Maximum Ratings (Design Center System)

The following maximum ratings are established under the Design Center System. Operating the tube beyond these limits can impair performance and tube life.

ParameterRatingUnit
Heater Voltage6.3V
Heater Current0.6A
Maximum DC Anode Voltage16,000V
Maximum DC Grid No. 2 Voltage410V
Maximum Grid No. 1 DC Negative-Bias Value125V
Maximum Grid No. 1 DC Positive-Bias Value0V
Maximum Grid No. 1 Circuit Resistance1.5MΩ

Heater-Cathode Voltage Limits

To prevent insulation breakdown between the heater and the cathode, the following peak voltage limits must be observed:

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

Typical Operating Conditions

Under typical operating conditions, the tube is operated with an anode potential of 12,000 V. The required grid voltages and focusing/ion-trap currents are detailed below:

  • 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 (Approximate): 100 ± 20% mA
  • DC Ion Trap Current (Standard Coil #111, Approximate): 75 ± 50% mA

Focusing and Ion Trap Specifications

The typical focusing coil current of 100 ± 20% mA is specified for a Standard Focus Coil #109 (or equivalent). This specification applies when the combined Grid No. 1 bias voltage and video signal voltage are adjusted to produce a highlight brightness of 30 foot-lamberts on the standard 10 1/8" by 13 1/2" picture size. The physical placement of the focus coil requires that the distance from the reference line to the center of the air gap on the focus coil be exactly 3.50 inches.

The ion trap requires an external single-field ion trap magnet. When using a Standard Coil #111, the typical current is 75 ± 50% mA to properly align the electron beam and prevent ion burn on the phosphor screen.

Technical Summary

The 16RP4 and 16RP4A are 16-inch rectangular glass cathode ray tubes designed for television display applications. Operating with a nominal 6.3 V, 0.6 A heater, they feature magnetic focus and deflection (with a 70-degree diagonal deflection angle), a grey filter faceplate, and require an external single-field ion trap. The 16RP4A is distinguished by its aluminized screen, which provides higher brightness than the non-aluminized 16RP4. Both types utilize a Small Shell Duodecal 5-pin base (B5-57) with a 12N pinout and a recessed small cavity cap (J1-21) for the high-voltage anode connection. Under typical operating conditions, they run at an anode voltage of 12,000 V and a Grid No. 2 voltage of 300 V, requiring a Grid No. 1 bias of -33 V to -77 V for spot extinction.

Socket description

Small-shell Duodecal 5-contact CRT base

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
12N
Socket code
DUODECAL5
Base pins
5
Nominal heater voltage
6.3 V
Nominal heater current
600 mA
Parallel heater voltage
-
Parallel heater current
-
Series capable
No

12N - Terminal pinout

Electrical assignments shared by every tube using this base designation.

No verified pinout is recorded for this base designation.

Section ratings

1 physical section, each with unique specifications.

Section 1

Cathode Ray

X-ray radiationInterelectrode capacitances
Max plate voltage
16000 V
Max screen voltage
41 V

CRT-specific anode/focus/deflection ratings retained as parameters rather than mapped to ordinary plate/screen fields.

Source-dependent data

Operating conditions by source

Each block preserves the test conditions and published values from one reference. Values from different sources are intentionally kept separate.

Data set 01

1961 Tung Sol

Published operating points and test conditions from this source.

SECTION 1

Cathode Ray

Other

  • Maximum Anode Voltage

    16000 V

  • Typical Anode Voltage

    12000 V

  • Maximum Grid2 Voltage

    410 V

  • Typical Grid2 Voltage

    300 V

Characteristic

  • DeflectionAngleApproximate

    70 degree

  • FocusingMethod

    Magnetic

  • DeflectingMethod

    Magnetic

  • PhosphorNumber

    4

  • FluorescentColor

    White

  • Persistence

    Medium

Data set 02

1966 Tung Sol Electronic Tubes 4 of 4

Published operating points and test conditions from this source.

SECTION 1

Cathode Ray

Characteristics

  • MAGNETIC FOCUS b DEFLECTION — value 1

    13 mA

    Published CRT datasheet value; multiple values on a row represent the source table's separate conditions/limits.

  • MAGNETIC FOCUS b DEFLECTION — value 2

    1 mA

    Published CRT datasheet value; multiple values on a row represent the source table's separate conditions/limits.

  • MAGNETIC FOCUS b DEFLECTION — value 3

    2 mA

    Published CRT datasheet value; multiple values on a row represent the source table's separate conditions/limits.

  • HEATER

    6.3 V

    Published CRT datasheet value; multiple values on a row represent the source table's separate conditions/limits.

  • OC ANODE VOLTAGE

    12000 V

    Published CRT datasheet value; multiple values on a row represent the source table's separate conditions/limits.

  • OC GRID #2 VOLTAGE — value 1

    2 V

    Published CRT datasheet value; multiple values on a row represent the source table's separate conditions/limits.

  • OC GRID #2 VOLTAGE — value 2

    3 V

    Published CRT datasheet value; multiple values on a row represent the source table's separate conditions/limits.

  • DC GRID #i VOLTAGE A

    77 V

    Published CRT datasheet value; multiple values on a row represent the source table's separate conditions/limits.

  • OC FOCUSING COIL CURRENT S (APPROX.)

    2 mA

    Published CRT datasheet value; multiple values on a row represent the source table's separate conditions/limits.

  • DC ION TRAP CURRENT STANDARD COIL #111 (APPROX.) — value 1

    111 mA

    Published CRT datasheet value; multiple values on a row represent the source table's separate conditions/limits.

  • DC ION TRAP CURRENT STANDARD COIL #111 (APPROX.) — value 2

    75 mA

    Published CRT datasheet value; multiple values on a row represent the source table's separate conditions/limits.

  • DC ION TRAP CURRENT STANDARD COIL #111 (APPROX.) — value 3

    5 mA

    Published CRT datasheet value; multiple values on a row represent the source table's separate conditions/limits.

  • DFOR STANDARD FOCUS COIL N109 r OR EDUIVALEXT r WITH THE COMBINED GRID #1 BIAS VOLTAGE AND VI DEC

    1 V

    Published CRT datasheet value; multiple values on a row represent the source table's separate conditions/limits.

  • SIGNAL VOLTAGE ADJUSTED TO PRODUCE A NiGXL IGHT BRIGMTNEGG OF j0 F00T LAMBERTS OX A 10 1/8" — value 1

    10 V

    Published CRT datasheet value; multiple values on a row represent the source table's separate conditions/limits.

  • SIGNAL VOLTAGE ADJUSTED TO PRODUCE A NiGXL IGHT BRIGMTNEGG OF j0 F00T LAMBERTS OX A 10 1/8" — value 2

    1 V

    Published CRT datasheet value; multiple values on a row represent the source table's separate conditions/limits.

  • SIGNAL VOLTAGE ADJUSTED TO PRODUCE A NiGXL IGHT BRIGMTNEGG OF j0 F00T LAMBERTS OX A 10 1/8" — value 3

    8 V

    Published CRT datasheet value; multiple values on a row represent the source table's separate conditions/limits.

  • lj 1/2" PICTURE SIZE. DISTANCE FROM REFERENCE LINE TO CENTER OF AIR GAP OX FOCUS COIL GN ALL BE — value 1

    1

    Published CRT datasheet value; multiple values on a row represent the source table's separate conditions/limits.

  • lj 1/2" PICTURE SIZE. DISTANCE FROM REFERENCE LINE TO CENTER OF AIR GAP OX FOCUS COIL GN ALL BE — value 2

    2

    Published CRT datasheet value; multiple values on a row represent the source table's separate conditions/limits.

Other

  • MAXIMUM DC ANODE

    16000 V

    Published CRT datasheet value; multiple values on a row represent the source table's separate conditions/limits.

  • MAXIMUM DC GRID #2 VOLTAGE — value 1

    2 V

    Published CRT datasheet value; multiple values on a row represent the source table's separate conditions/limits.

  • MAXIMUM DC GRID #2 VOLTAGE — value 2

    41 V

    Published CRT datasheet value; multiple values on a row represent the source table's separate conditions/limits.

  • MAXIMUM GRID #1 CIRCUIT RESISTANCE — value 1

    1 mA

    Published CRT datasheet value; multiple values on a row represent the source table's separate conditions/limits.

  • MAXIMUM GRID #1 CIRCUIT RESISTANCE — value 2

    1.5 mA

    Published CRT datasheet value; multiple values on a row represent the source table's separate conditions/limits.