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19DP4A

Nineteen-inch direct-view television picture tube with magnetic focusing, approximately 56-degree deflection, and a white P4 medium-persistence screen. It provides a large monochrome image for conventional receiver display service.

Directly heatedCold cathodeCommon cathodeDissimilarSpecialized

Sections: 1
Base: 12N
Socket code: DUODECAL5
Base pins: 5
Nominal heater: 6.3 V / 600 mA

Description

19DP4A — Direct-View Television Picture Tube

The 19DP4A is a direct-view, round glass picture tube designed primarily for television receiver applications. It features magnetic focus and magnetic deflection, utilizing a unipotential cathode and an external single-field ion trap. The tube is constructed with an external conductive coating that, when grounded, serves as a filter capacitor in the high-voltage anode circuit.

A key distinction between the 19DP4A and its predecessor, the 19DP4, lies in the faceplate treatment: while the standard 19DP4 uses a clear glass faceplate, the 19DP4A is equipped with a grey filter faceplate to improve picture contrast under ambient room lighting.

Physical and Mechanical Specifications

The 19DP4A is a physically substantial cathode-ray tube with a round glass envelope. Its mechanical dimensions and alignment tolerances are highly specified to ensure proper mounting and deflection yoke positioning:

Greatest Diameter of Bulb: 18 7/8 ± 1/8 inches
Overall Length: 21 1/2 ± 3/8 inches
Minimum Useful Screen Diameter: 17 3/8 inches
Typical Raster Size: 11 3/4" x 15 3/4"

The tube uses a small shell duodecal 5-pin base (designated B5-57) with a 12N basing configuration. High-voltage anode connection is made via a recessed small cavity cap (J1-21) located on the bulb cone. This anode contact is precisely aligned with pin position #3 within a tolerance of ±10 degrees to facilitate neat and safe high-voltage cabling.

Heater and Pin Connections

The 19DP4A is equipped with an indirectly heated unipotential cathode. The heater is designed for parallel operation in television chassis.

Heater Parameter	Value
Nominal Heater Voltage	6.3 V
Nominal Heater Current	0.6 A
Calculated Heater Power	3.78 W

The bottom-view pinout configuration of the B5-57 base and the anode cap is defined as follows:

Pin / Connection	Electrode
Pin 1	Heater
Pin 2	Grid No. 1 (Control Grid)
Pin 10	Grid No. 2 (Screen Grid)
Pin 11	Cathode
Pin 12	Heater
Anode Cap (J1-21)	Anode (Grid No. 3 / Screen / Collector)

Optical Characteristics

The screen of the 19DP4A utilizes Phosphor No. 4, which is optimized for monochrome television display.

Fluorescent Color: White
Phosphorescent Color: White
Persistence: Medium
Faceplate Light Transmission: Approximately 70% at the center of the screen (specifically enabled by the grey filter glass of the "A" variant).

Interelectrode Capacitances and Deflection

The external conductive coating on the bulb envelope forms a capacitor with the internal anode coating. The capacitance values are:

External Conductive Coating to Anode (Maximum): 2,500 μμf
External Conductive Coating to Anode (Minimum): 750 μμf

The tube is designed for a nominal deflection angle of 56 degrees, requiring standard magnetic deflection yoke components.

Design Center Ratings

The following absolute maximum and minimum limits are established under the Design Center Rating System. Operating the tube beyond these limits can impair performance and shorten its service life.

Parameter	Rating
Maximum DC Anode Voltage	17,000 V
Maximum DC Grid No. 2 Voltage	410 V
Maximum DC Negative-Bias Grid No. 1 Value	125 V
Maximum DC Positive-Bias Grid No. 1 Value	0 V
Maximum Positive-Peak Grid No. 1 Value	2 V
Maximum DC Peak Heater-Cathode Voltage (Heater negative, warm-up ≤ 15s)	410 V
Maximum DC Peak Heater-Cathode Voltage (Heater negative, after warm-up)	125 V
Maximum DC Peak Heater-Cathode Voltage (Heater positive)	125 V

The maximum allowable control grid (Grid No. 1) circuit resistance is 1.5 Megohms.

Typical Operating Conditions

Under typical operating conditions, the 19DP4A is operated with an anode potential of 13,000 Volts. Focusing and ion-trap alignment require external magnetic fields adjusted to specific current levels.

Parameter	Typical Value
DC Anode Voltage	13,000 V
DC Grid No. 2 Voltage	250 V
DC Grid No. 1 Voltage (for visual extinction of undeflected focused spot)	-26 to -63 V
DC Focusing Coil Current (Approximate)	146 mA
DC Ion Trap Current (Approximate, Standard Coil)	75 ± 50% mA

The typical focusing coil current of 146 mA is specified using a standard focus coil #109 (or equivalent), with the focus coil air gap center positioned 3.25 inches from the reference line. This operating point is measured with the combined Grid No. 1 bias and video signal adjusted to produce a highlight brightness of 25 foot-lamberts on the standard 11 3/4" x 15 3/4" picture area.

Technical Summary

The 19DP4A is a 19-inch class, round glass television picture tube featuring a grey filter faceplate with approximately 70% light transmission for enhanced contrast. It utilizes magnetic focus and 56-degree magnetic deflection, requiring an external single-field ion trap and a standard focusing coil. Operating at a typical anode voltage of 13,000 V (with a design center maximum of 17,000 V), the tube provides a white-phosphor monochrome display (Phosphor No. 4) with medium persistence. Its electrical interface consists of a small shell duodecal 5-pin base and a recessed small cavity anode cap, supported by a standard 6.3 V, 0.6 A heater.

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: 1 V
Max screen voltage: 41 V

CRT-specific electrode, focusing and deflection data retained as parameters.

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
17000 V
Typical Anode Voltage
13000 V
Maximum Grid2 Voltage
410 V
Typical Grid2 Voltage
250 V

Characteristic

DeflectionAngleApproximate
56 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

11 3~'a" % 15 3~N" RASTER SIZE — value 1
3
Published CRT datasheet value; multiple values on a row correspond to separate source-table conditions or limits.
11 3~'a" % 15 3~N" RASTER SIZE — value 2
15
Published CRT datasheet value; multiple values on a row correspond to separate source-table conditions or limits.
11 3~'a" % 15 3~N" RASTER SIZE — value 3
3
Published CRT datasheet value; multiple values on a row correspond to separate source-table conditions or limits.
DEFLECTION ANGLE (APPROX.)
56 degrees
Published CRT datasheet value; multiple values on a row correspond to separate source-table conditions or limits.
HEATER POSITIVE WITH RESPECT TO CATHODE
125 V
Published CRT datasheet value; multiple values on a row correspond to separate source-table conditions or limits.
OC ION TRAP CURRENT STANDARD COIL (APPROX.)
75 mA
Published CRT datasheet value; multiple values on a row correspond to separate source-table conditions or limits.
FO R, STANDARD FOCUS COIL 1109, OR — value 1
1109 V
Published CRT datasheet value; multiple values on a row correspond to separate source-table conditions or limits.
FO R, STANDARD FOCUS COIL 1109, OR — value 2
111 V
Published CRT datasheet value; multiple values on a row correspond to separate source-table conditions or limits.
VIDEO SIGNAL
25 V
Published CRT datasheet value; multiple values on a row correspond to separate source-table conditions or limits.
11 3/µ" BY 15 3/µ+ PICTURE SIZE. — value 1
3
Published CRT datasheet value; multiple values on a row correspond to separate source-table conditions or limits.
11 3/µ" BY 15 3/µ+ PICTURE SIZE. — value 2
15
Published CRT datasheet value; multiple values on a row correspond to separate source-table conditions or limits.
11 3/µ" BY 15 3/µ+ PICTURE SIZE. — value 3
3
Published CRT datasheet value; multiple values on a row correspond to separate source-table conditions or limits.

Other

MAXIMUM OC ANODE VOLTAGE
1 V
Published CRT datasheet value; multiple values on a row correspond to separate source-table conditions or limits.
MAXIMUM DC GRID #2 VOLTAGE — value 1
2 V
Published CRT datasheet value; multiple values on a row correspond to separate source-table conditions or limits.
MAXIMUM DC GRID #2 VOLTAGE — value 2
41 V
Published CRT datasheet value; multiple values on a row correspond to separate source-table conditions or limits.
MAXIMUM GRID #1 VOLTAGE
1 V
Published CRT datasheet value; multiple values on a row correspond to separate source-table conditions or limits.
MAXIMUM GR 10 #i CIRCUIT RESISTANCE — value 1
10 mA
Published CRT datasheet value; multiple values on a row correspond to separate source-table conditions or limits.
MAXIMUM GR 10 #i CIRCUIT RESISTANCE — value 2
1.5 mA
Published CRT datasheet value; multiple values on a row correspond to separate source-table conditions or limits.