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Specialized - Cathode Ray ·CathodeRay

11CP4

Eleven-inch P4 cathode-ray picture tube using magnetic deflection for direct-view display. Published operating data place the anode around 12 kV, with a substantial projected screen area suited to television-picture presentation.

Directly heatedCold cathodeCommon cathodeDissimilarSpecialized
Sections
1
Base
-
Socket code
-
Base pins
7
Nominal heater
6.9 V / 20 A

Description

11CP4

The 11CP4 is a PAN-O-PLY type cathode-ray picture tube designed for television display applications. It features a 110-degree magnetic deflection system and a low-voltage electrostatic focus system. The tube incorporates an aluminized, sulfide-type P4 phosphor screen, a filterglass faceplate, and integrated implosion protection hardware.

Mechanical Design and Physical Dimensions

The 11CP4 utilizes the J87A bulb outline. Its physical dimensions and mechanical characteristics are highly specified to ensure precise mounting and alignment:

  • Screen Dimensions: The screen has a minimum diagonal of 10.125 inches, a minimum height of 7.125 inches, and a minimum width of 8.938 inches. The projected area of the screen is 60 square inches.
  • Overall Bulb Dimensions: The overall width is 9.750 ± 0.125 inches, the overall height is 8.000 ± 0.125 inches, and the diagonal dimension is 10.875 ± 0.125 inches.
  • Length and Neck: The overall length of the tube is 8.785 ± 0.250 inches. The neck length is 4.125 ± 0.125 inches, with a neck diameter of 1.125 (+0.043 / -0.025) inches.
  • Deflection Angles: The tube is designed for a diagonal deflection angle of 110°, a horizontal deflection angle of 99°, and a vertical deflection angle of 82°.
  • Weight: The approximate weight of the tube is 4 pounds, which includes the integrated implosion protection hardware.
  • Reference Line: The reference line of the bulb is determined by the JEDEC No. G-126 gauge.

Electrical Connections and Basing

The 11CP4 is equipped with a JEDEC No. B7-208 base, which is a small-button Neoeightar 7-pin base (Arrangement 1). The basing configuration is designated as 8HR. High-voltage anode connection is made via a recessed small cavity cap (JEDEC No. J1-21) located on the bulb funnel.

The terminal connections, viewed from the bottom of the base, are assigned as follows:

PinConnection
Pin 1Heater
Pin 2Grid No. 1
Pin 3Grid No. 2
Pin 4Grid No. 4
Pin 6Grid No. 1
Pin 7Cathode
Pin 8Heater
CapAnode (Grid No. 3, Grid No. 5, Screen, Collector)
CExternal Conductive Coating

The external conductive coating is a Regular-Band type. The contact area for grounding this coating is located near the reference line.

Heater and Electrostatic Characteristics

The tube's electron gun is designed to operate without requiring an external ion-trap magnet. The electrical characteristics of the heater and the interelectrode capacitances are detailed below:

  • Heater Voltage: 6.3 V nominal (with a design-maximum range of 5.7 V minimum to 6.9 V maximum).
  • Heater Current: 450 ± 20 mA at 6.3 V.
  • Heater Warm-Up Time: An average of 11 seconds.
  • Cathode to All Other Electrodes Capacitance: 5 pF.
  • Grid No. 1 to All Other Electrodes Capacitance: 6 pF.
  • External Conductive Coating to Anode Capacitance: 500 pF minimum to 750 pF maximum.

Maximum Ratings and Typical Operating Conditions

The maximum and minimum ratings are defined under the Design-Maximum rating system. All voltages are positive with respect to the cathode unless otherwise specified.

Design-Maximum Ratings

ParameterMinimum ValueMaximum Value
Anode Voltage8,000 V15,000 V
Grid-No. 4 (Focusing Electrode) Voltage-550 V+1,100 V
Grid-No. 2 Voltage200 V550 V
Grid-No. 1 Negative Peak Voltage—220 V
Grid-No. 1 Negative Bias Voltage—155 V
Grid-No. 1 Positive Bias Voltage—0 V
Grid-No. 1 Positive Peak Voltage—2 V
Heater Voltage5.7 V6.9 V

Peak Heater-Cathode Voltage Limits

  • Heater Negative with Respect to Cathode:
    • During equipment warm-up period (less than or equal to 15 seconds): 450 V maximum.
    • After equipment warm-up period: 300 V maximum.
  • Heater Positive with Respect to Cathode:
    • Combined AC and DC voltage: 200 V maximum.
    • DC component: 100 V maximum.

Typical Operating Conditions (Grid-Drive Service)

Under typical grid-drive operating conditions, the electrode voltages are configured as follows:

  • Anode Voltage: 12,000 V
  • Grid-No. 4 Voltage: 0 to 400 V
  • Grid-No. 2 Voltage: 400 V
  • Grid-No. 1 Voltage (for visual extinction of focused raster): -39 to -94 V

The maximum circuit resistance for the Grid-No. 1 circuit must not exceed 1.5 MΩ.

Optical Characteristics

The 11CP4 features a specialized optical design optimized for television display clarity:

  • Phosphor: Sulfide-type, aluminized P4 phosphor.
  • Faceplate: Constructed of filterglass to enhance contrast.
  • Light Transmission: Approximately 79% light transmission at the center of the faceplate.

Technical Summary

The 11CP4 is a compact, 110-degree magnetic deflection picture tube utilizing low-voltage electrostatic focusing. Its mechanical design features a J87A bulb with integrated implosion protection, weighing approximately 4 pounds. Electrically, it operates with a 6.3 V heater drawing 450 mA, and is rated for anode voltages up to 15,000 V. The tube uses a small-button Neoeightar 7-pin base and a recessed small cavity cap for the high-voltage anode connection. With its aluminized P4 sulfide phosphor and 79% transmission filterglass faceplate, the 11CP4 provides a reliable, high-contrast display solution for grid-drive television receiver service.

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
-
Socket code
-
Base pins
7
Nominal heater voltage
6.9 V
Nominal heater current
20 A
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
Max screen voltage
550 V

CRT-specific ratings, operating conditions, capacitances, focus/deflection, cutoff, optical, and screen data are retained in section 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

1971 RCA HB3 Binder 1 of 7

Published operating points and test conditions from this source.

SECTION 1

Cathode Ray

Characteristics

  • I 10° MAGNETIC DEFLECTION

    10 V

    Published CRT datasheet value; multiple numbers on one source row represent its separate limits or operating conditions.

  • Grid No.ltoallotherelectrodes

    6 pF

    Published CRT datasheet value; multiple numbers on one source row represent its separate limits or operating conditions.

  • External conductive coating to anode — published value 1

    500 mA

    Published CRT datasheet value; multiple numbers on one source row represent its separate limits or operating conditions.

  • External conductive coating to anode — published value 2

    750 mA

    Published CRT datasheet value; multiple numbers on one source row represent its separate limits or operating conditions.

  • Heater Current at 6.3 V — published value 1

    6.3 mA

    Published CRT datasheet value; multiple numbers on one source row represent its separate limits or operating conditions.

  • Heater Current at 6.3 V — published value 2

    450 mA

    Published CRT datasheet value; multiple numbers on one source row represent its separate limits or operating conditions.

  • Heater Current at 6.3 V — published value 3

    20 mA

    Published CRT datasheet value; multiple numbers on one source row represent its separate limits or operating conditions.

  • Light transmission at center (approx.)

    79

    Published CRT datasheet value; multiple numbers on one source row represent its separate limits or operating conditions.

  • Projected Area of Screen

    60

    Published CRT datasheet value; multiple numbers on one source row represent its separate limits or operating conditions.

  • Anode Voltage — published value 1

    8000 V

    Published CRT datasheet value; multiple numbers on one source row represent its separate limits or operating conditions.

  • Anode Voltage — published value 2

    15000 V

    Published CRT datasheet value; multiple numbers on one source row represent its separate limits or operating conditions.

  • Grid-No.2 Voltage — published value 1

    200 V

    Published CRT datasheet value; multiple numbers on one source row represent its separate limits or operating conditions.

  • Grid-No.2 Voltage — published value 2

    550 V

    Published CRT datasheet value; multiple numbers on one source row represent its separate limits or operating conditions.

  • Heater Voltage — published value 1

    5.7 V

    Published CRT datasheet value; multiple numbers on one source row represent its separate limits or operating conditions.

  • Heater Voltage — published value 2

    6.9 V

    Published CRT datasheet value; multiple numbers on one source row represent its separate limits or operating conditions.

  • Combined AC & DC voltage

    200 V

    Published CRT datasheet value; multiple numbers on one source row represent its separate limits or operating conditions.

  • Anode Voltage

    12000 V

    Published CRT datasheet value; multiple numbers on one source row represent its separate limits or operating conditions.

  • Grid-No.4 Voltage — published value 1

    0 V

    Published CRT datasheet value; multiple numbers on one source row represent its separate limits or operating conditions.

  • Grid-No.4 Voltage — published value 2

    400 V

    Published CRT datasheet value; multiple numbers on one source row represent its separate limits or operating conditions.

  • Grid-No.2 Voltage

    400 V

    Published CRT datasheet value; multiple numbers on one source row represent its separate limits or operating conditions.

  • Grid-No. l Voltage — published value 1

    -39 V

    Published CRT datasheet value; multiple numbers on one source row represent its separate limits or operating conditions.

  • Grid-No. l Voltage — published value 2

    -94 V

    Published CRT datasheet value; multiple numbers on one source row represent its separate limits or operating conditions.

  • Grid-No. l Circuit Resistance — published value 1

    1 mA

    Published CRT datasheet value; multiple numbers on one source row represent its separate limits or operating conditions.

  • Grid-No. l Circuit Resistance — published value 2

    5 mA

    Published CRT datasheet value; multiple numbers on one source row represent its separate limits or operating conditions.