Skip to main content
Tube Tinker — Electron Tube Database
Alternatives & variationsDownload PDF datasheet

Specialized - Cathode Ray ·CathodeRay

27ACP4

Twenty-seven-inch direct-view monochrome television picture tube with magnetic deflection and high-voltage operation. Manufacturer documentation provides focusing, optical, and electrical characteristics for large-screen receiver display service.

Directly heatedCold cathodeCommon cathodeDissimilarSpecialized
Sections
1
Base
86-203
Socket code
NEOEIGHTAR7
Base pins
-
Nominal heater
6.3 V / -

Description

Twenty-seven-inch bonded-shield television CRT with electrostatic focus, magnetic deflection, aluminized P4 screen, and no ion trap.

Socket description

Small-button Neoeightar 7-contact CRT base family

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
86-203
Socket code
NEOEIGHTAR7
Base pins
-
Nominal heater voltage
6.3 V
Nominal heater current
-
Parallel heater voltage
-
Parallel heater current
-
Series capable
No

86-203 - 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
11 V
Max screen voltage
550 V

Electrical section extracted from supplied datasheet.

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

1950 Sylvania

Published operating points and test conditions from this source.

SECTION 1

Cathode Ray

Characteristic

  • Heater Voltage . . . . . . . . . . . . . ... .. 6.3 Volts

    6.3 V

    Heater Voltage . . . . . . . . . . . . . ... .. 6.3 Volts

  • Minimum Anode Voltage . . . . . . . . . . . . .. 11,000 Volts dc

    11 V

    Minimum Anode Voltage . . . . . . . . . . . . .. 11,000 Volts dc

  • Grid No. 4 Voltage (Focusing Electrode) . . . .-550 to +1100 Volts dc

    1100 V

    Grid No. 4 Voltage (Focusing Electrode) . . . .-550 to +1100 Volts dc

  • Minimum Grid No. 2Voltage . . . . . . . . . . .. 200 Volts dc SYLVANIA

    200 V

    Minimum Grid No. 2Voltage . . . . . . . . . . .. 200 Volts dc SYLVANIA

  • Minimum Anode Voltage . . . . . . . . .. L. 0oL oo 11,000 Volts dc

    11 V

    Minimum Anode Voltage . . . . . . . . .. L. 0oL oo 11,000 Volts dc

  • Grid No. 4 Voltage (Focusing Electrode) . . . . . . . . . . . . .. ... .. —400 to +1250 Volts dc

    1250 V

    Grid No. 4 Voltage (Focusing Electrode) . . . . . . . . . . . . .. ... .. —400 to +1250 Volts dc

  • Minimum Grid No. 2 Voltage . . . . . . . . . . . . . ..o 0oL 350 Volts dc

    350 V

    Minimum Grid No. 2 Voltage . . . . . . . . . . . . . ..o 0oL 350 Volts dc

  • Anode Voltage . . . . . . . . .. ..o e e 18,000 Volts dc

    18 V

    Anode Voltage . . . . . . . . .. ..o e e 18,000 Volts dc

  • Grid No. 4 Voltage for Focus . . . . . . . . . . . . . ..o L. 0 to 400 Volts dc

    400 V

    Grid No. 4 Voltage for Focus . . . . . . . . . . . . . ..o L. 0 to 400 Volts dc

  • Grid No. 2 Voltage . . . . . . . . . .« L 400 Volts dc

    400 V

    Grid No. 2 Voltage . . . . . . . . . .« L 400 Volts dc

  • Grid No. 1 Voltage Required for Cutoff®> . . . . . . . . . .. ... ... .. —48 to —96 Volts dc

    96 V

    Grid No. 1 Voltage Required for Cutoff®> . . . . . . . . . .. ... ... .. —48 to —96 Volts dc

  • Anode Voltage . . . . . . . . .. ..o Lo 18,000 Volts dc

    18 V

    Anode Voltage . . . . . . . . .. ..o Lo 18,000 Volts dc

  • Grid No. 4 Voltage for Focus . . . . . . . . . . . . . . . ... 0 to 400 Volts dc

    400 V

    Grid No. 4 Voltage for Focus . . . . . . . . . . . . . . . ... 0 to 400 Volts dc

  • Grid No. 2 Voltage . . . . . . . . . . . . 400 Volts dc

    400 V

    Grid No. 2 Voltage . . . . . . . . . . . . 400 Volts dc

  • Cathode Voltage Required for Cutoff® . . . . . . . . . . .. .. ... ... +46 to +80 Volts dc

    80 V

    Cathode Voltage Required for Cutoff® . . . . . . . . . . .. .. ... ... +46 to +80 Volts dc

  • 5. Visual extinction offocused raster. Exiinction of stationary focused spor will vequire that these

    5 V

    5. Visual extinction offocused raster. Exiinction of stationary focused spor will vequire that these values be increased by about 5 volts.

Other

  • Maximum Anode Voltage . . . . . . . . . . . .. 25,000 Volts dc

    25 V

    Maximum Anode Voltage . . . . . . . . . . . .. 25,000 Volts dc

  • Maximum Grid No. 2 Voltage . . . . . . . . . . . . 550 Volts dc

    550 V

    Maximum Grid No. 2 Voltage . . . . . . . . . . . . 550 Volts dc

  • Maximum Anode Voltage . . . . . . . . . . . . ..o 25,000 Volts dc

    25 V

    Maximum Anode Voltage . . . . . . . . . . . . ..o 25,000 Volts dc

  • range if this tube is operated ar higher than the manufacturer’s Maximum Rated Anode Voltage or 16,0

    16 V

    range if this tube is operated ar higher than the manufacturer’s Maximum Rated Anode Voltage or 16,000 volts, whichever is less.

Data set 02

1965 Sylvania Electronic Tubes Vol3

Published operating points and test conditions from this source.

SECTION 1

Cathode Ray

Characteristic

  • Heater voltage

    6.3 V

    Heater voltage ............... . . 6.3Volts

Other

  • Maximum Anode voltage

    25000 V

    Maximum Anode voltage ...... .... 25,000Volts

  • Maximum Grid No. 2 Voltage

    550 V

    Maximum Grid No. 2 Voltage ..... .... 550Volts

  • Minimum Grid No. 2 Voltage

    200 V

    Minimum Grid No. 2 Voltage ..... .... 200Volts SYLVANIA

  • Heater positive with Respect to cathode

    200 V

    Heater positive with Respect to cathode .... 200 Volts EiMPORIUM. PENNSYLVANIA

  • Anode voltage

    18000 V

    Anode voltage ......................... • . 18,000Volts

  • Anode voltage

    0 V

    Anode voltage ......................... • . |8'000Volts

  • Cathode voltage Required for cutoff5

    80 V

    Cathode voltage Required for cutoff5 ............... +46 to +80 Volts

CircuitValue

  • Grid No. 1 Circuit Resistahce

    1.5 Mohm

    Grid No. 1 Circuit Resistahce ........................... 1.5 Megohms Max.