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Specialized - Cathode Ray ·CathodeRay

19EJP4

Wide-angle aluminized P4 monochrome television picture tube using electrostatic focusing and magnetic deflection, designed for high-voltage direct-view service with a large approximately 19-inch screen.

Directly heatedCold cathodeCommon cathodeDissimilarSpecialized
Sections
1
Base
-
Socket code
DUODECAL5
Base pins
-
Nominal heater
6.3 V / 450 mA

Description

19EJP4 Television Picture Tube

The 19EJP4 is a television picture tube designed with a 114-degree magnetic deflection system and low-voltage electrostatic focusing. It features an aluminized P4 phosphor screen with spherical gray filter glass, providing approximately 49% light transmittance at the center. The tube incorporates a tension band for implosion protection and an external conductive coating that serves as a supplementary filter capacitance.

Mechanical and Screen Characteristics

The 19EJP4 is constructed with an EIA J149F1 glass bulb and utilizes an EIA B7-208 small button 7-pin base. The physical dimensions of the tube are characterized by the following specifications:

  • Overall Length: 11.625 inches ± 0.250 inches
  • Neck Length: 4.375 inches ± 0.125 inches
  • Neck Diameter: 1.168 inches maximum at the splice
  • Greatest Diagonal: 18.733 inches ± 0.125 inches
  • Greatest Width: 16.552 inches ± 0.125 inches
  • Greatest Height: 13.446 inches ± 0.125 inches
  • Net Weight: 15 lbs

The screen provides a minimum useful projected area of 172 square inches, with the following minimum dimensions:

  • Diagonal: 17.562 inches
  • Horizontal: 15.188 inches
  • Vertical: 12 inches

For safety and proper operation, the tension band and the external conductive coating must be grounded. The electrical resistance between the external coating and the tension band is a minimum of 5 Megohms.

Heater and Electrical Connections

The 19EJP4 features an indirectly heated cathode with a controlled warm-up time.

ParameterValue
Heater Voltage6.3 V
Heater Current450 ± 5% mA
Heater Warm-up Time11 seconds

The heater warm-up time is defined as the time required to reach 80% of the rated voltage under a specified series resistance test.

The tube uses the EIA 8HR basing configuration. The pin connections, viewed from the bottom of the base, are as follows:

Pin NumberConnection
Pin 1Heater
Pin 2Grid No. 1
Pin 3Grid No. 2
Pin 4Grid No. 4 (Focusing Electrode)
Pin 6Grid No. 1
Pin 7Cathode
Pin 8Heater
Anode CapRecessed small cavity (EIA J1-21)

Base pin 4 aligns with the major axis of the tube within 30 degrees and is located on the same side as the anode terminal. To prevent mechanical damage, the socket must be equipped with flexible leads to avoid lateral strains on the pins.

Direct Interelectrode Capacitances

The direct interelectrode capacitances of the tube are:

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

Absolute Maximum Ratings

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

ParameterMinimumMaximum
Anode Voltage12,000 V20,000 V
Grid No. 4 (Focusing Electrode) Voltage-550 V+1,100 V
Grid No. 2 Voltage20 V60 V
Cathode Voltage (Positive Bias)—154 V
Cathode Voltage (Positive Peak)—220 V
Cathode Voltage (Negative Bias)—0 V
Cathode Voltage (Negative Peak)—2 V

Heater-Cathode Voltage Limits

  • Heater negative with respect to cathode (during warm-up, <= 15 seconds): 450 V maximum
  • Heater negative with respect to cathode (after warm-up): 300 V maximum
  • Heater positive with respect to cathode: 200 V maximum

Typical Operating Conditions and Circuit Limits

In typical cathode drive operation, the voltages are applied with respect to Grid No. 1:

  • Anode Voltage: 16,000 V
  • Grid No. 4 Voltage: 0 to 400 V
  • Grid No. 2 Voltage: 30 V
  • Cathode Voltage for Raster Cutoff: 30 to 45 V

When operating the 19EJP4 at anode voltages exceeding 16,000 V, appropriate shielding may be required to limit very soft X-ray radiation.

Circuit Resistance Limits

  • Maximum Grid No. 1 Circuit Resistance: 1.5 Megohms
  • Minimum Grid No. 2 and Grid No. 4 Circuit Resistance: 10,000 Ohms (protective resistance is advisable to prevent damage to the electrodes)

Centering Magnet Requirements

A permanent magnet (PM) centering magnet providing a field of 0 to 8 gauss may be used. This magnet should extend no more than 2.125 inches from the Yoke Reference Line, as determined by JEDEC Reference Line Gauge No. 126.

Technical Summary

The 19EJP4 is a 15-pound, 114-degree magnetic deflection television picture tube utilizing low-voltage electrostatic focusing and an aluminized P4 phosphor screen. Operating with a 6.3 V, 450 mA heater, it features a controlled 11-second warm-up time. The tube is designed for cathode-drive service, typically operating with a 16,000 V anode supply, a low Grid No. 2 voltage of 30 V, and a focusing voltage range of 0 to 400 V. It incorporates essential safety and performance features, including tension band implosion protection and an external conductive coating, both of which must be grounded.

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
-
Socket code
DUODECAL5
Base pins
-
Nominal heater voltage
6.3 V
Nominal heater current
450 mA
Parallel heater voltage
-
Parallel heater current
-
Series capable
No

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

No fixed ratings are recorded for this section.

Television CRT electron-gun/display section.

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

1965 Westinghouse Data Book

Published operating points and test conditions from this source.

SECTION 1

Cathode Ray

Characteristics

  • Heater Voltage

    6.3 V

  • Heater Current

    450 mA

  • Heater Warm-up Time

    11 s

  • Focusing Method

    Low Voltage Electrostatic text

  • Deflection Method

    Magnetic text

  • Horizontal Deflection Angle

    103 deg

    Approximate

  • Vertical Deflection Angle

    86 deg

    Approximate

  • Diagonal Deflection Angle

    114 deg

    Approximate

  • Phosphor

    Aluminized P4 text

  • Fluorescence

    White text

  • Persistence

    Short to Medium text

  • Light Transmittance

    49 percent

    Approximate

  • Cathode-to-All Capacitance

    5 pF

    Approximate

  • Grid1-to-All Capacitance

    6 pF

    Approximate

  • External Coating-to-Anode Capacitance Minimum

    1000 pF

  • External Coating-to-Anode Capacitance Maximum

    1500 pF

Other

  • Maximum Anode Voltage

    20000 V

  • Minimum Anode Voltage

    12000 V

  • Maximum Focus Electrode Voltage Positive

    1100 V

    Grid4

  • Maximum Focus Electrode Voltage Negative

    -550 V

    Grid4

  • Maximum Grid2 Voltage

    60 V

  • Minimum Grid2 Voltage

    20 V

  • Maximum Heater-Cathode Voltage During Warmup

    450 V

    Duration<=15s

  • Maximum Heater-Cathode Voltage After Warmup

    300 V

  • Typical Anode Voltage

    16000 V

    CathodeDrive

  • Typical Focus Voltage Minimum

    0 V

    Grid4

  • Typical Focus Voltage Maximum

    400 V

    Grid4

  • Typical Grid2 Voltage

    30 V

    CathodeDrive

  • Cathode Voltage for Raster Cutoff Minimum

    30 V

    CathodeDrive

  • Cathode Voltage for Raster Cutoff Maximum

    45 V

    CathodeDrive

  • Maximum Grid1 Circuit Resistance

    1.5 Mohm