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Specialized - Cathode Ray ·CathodeRay

19FEP4A

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

19FEP4A Television Picture Tube

The 19FEP4A is a television picture tube featuring a spherical gray filter glass screen, low-voltage electrostatic focusing, and a 114° magnetic deflection system. It utilizes an aluminized P4 phosphor screen and incorporates a tension band for implosion protection, eliminating the need for an external ion trap.

Mechanical and Physical Specifications

The 19FEP4A is constructed using the EIA J149F1 bulb envelope and has a net weight of 15 lbs. The screen features spherical gray filter glass with a light transmittance of approximately 49% at the center. Implosion protection is provided by a tension band, which must be grounded.

Physical Dimensions

  • Overall Length: 11.625" ± 0.250"
  • Greatest Diagonal: 18.733" ± 0.125"
  • Greatest Width: 16.552" ± 0.125"
  • Greatest Height: 13.446" ± 0.125"
  • Neck Length: 4.375" ± 0.125"
  • Maximum Neck Diameter at Splice: 1.168"

Screen Dimensions

The projected minimum useful screen dimensions provide a total useful area of 172 square inches:

  • Diagonal: 17.562"
  • Horizontal: 15.125"
  • Vertical: 12"

Deflection and Alignment

The tube utilizes magnetic deflection with a horizontal deflection angle of 103° and a vertical deflection angle of 86°, resulting in a diagonal deflection angle of 114°. The yoke reference line is determined by the plane surface of the flared end of JEDEC Reference Line Gauge No. 126. If a permanent magnet (PM) centering magnet (0 to 8 gauss) is used, it must extend no more than 2.125" from the Yoke Reference Line.

Electrical Connections and Heater Ratings

The 19FEP4A uses an EIA B7-208 small-button 7-pin base with an EIA 8HR basing configuration. The anode connection is made via an EIA J1-21 bulb contact.

Pin Connection Table

The pinout configuration for the EIA 8HR basing is detailed below:

Pin NumberElectrode Connection
Pin 1Heater (H)
Pin 2Grid No. 1 (G1)
Pin 3Grid No. 2 (G2)
Pin 4Grid No. 4 (G4, Focusing Electrode)
Pin 6Grid No. 1 (G1)
Pin 7Cathode (K)
Pin 8Heater (H)

Heater Characteristics

The heater is designed for a nominal voltage of 6.3 V and operates at a current of 450 ± 5% mA. Under specified test conditions, the heater has a warm-up time of 11 seconds to reach 80% of its rated voltage.

Electrostatic and Interelectrode Capacitances

The direct interelectrode capacitances and associated electrical characteristics of the envelope coatings are:

  • Cathode to all other electrodes: Approximately 5 pF
  • Grid No. 1 to all other electrodes: Approximately 6 pF
  • External conductive coating to anode: 1250 pF minimum to 1750 pF maximum
  • Minimum resistance from external coating to implosion hardware: 5 Megohms

Typical Operating Conditions (Cathode Drive)

Under typical cathode drive operation, where voltages are positive with respect to Grid No. 1, the operating parameters are established as follows:

ParameterTypical Value
Anode Voltage16,000 V
Grid No. 4 (Focusing Electrode) Voltage0 to 400 V
Grid No. 2 Voltage30 V
Cathode Voltage for Raster Cutoff30 to 45 V

Design Maximum Ratings and Circuit Limits

The following limiting values are specified under the Design Maximum System. All voltages are positive and measured with respect to Grid No. 1 unless otherwise noted.

Electrode Voltage Limits

  • Anode Voltage: 12,000 V minimum to 23,500 V maximum
  • Grid No. 4 (Focusing Electrode) Voltage: -550 V to +1100 V
  • Grid No. 2 Voltage: 20 V minimum to 60 V maximum
  • Cathode Voltage:
    • Maximum negative bias value: 0 V
    • Maximum negative peak value: 2 V
    • Maximum positive bias value: 154 V
    • Maximum positive peak value: 220 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: 200 V maximum
  • Heater positive with respect to cathode: 200 V maximum

Limiting Circuit Values

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

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

    1250 pF

  • External Coating-to-Anode Capacitance Maximum

    1750 pF

Other

  • Maximum Anode Voltage

    23500 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

    200 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