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21FMP4

Twenty-one-inch direct-view monochrome television picture tube with magnetic deflection and high-voltage operation. Manufacturer documentation describes its focusing system, picture-screen construction, and receiver-display characteristics for large-screen television service.

Directly heatedCold cathodeCommon cathodeDissimilarSpecialized

Sections: 1
Base: -
Socket code: -
Base pins: -
Nominal heater: 6.3 V / 600 mA

Description

The 21FMP4 is a 21-inch electrostatic-focus, magnetic-deflection glass picture tube with a non-ion-trap gun designed for low Grid No. 2 voltage cathode-drive operation, an aluminized screen, and external conductive coating.

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: -
Socket code: -
Base pins: -
Nominal heater voltage: 6.3 V
Nominal heater current: 600 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

Max plate voltage: 22000 V

Maximum anode voltage mapped to MaxPlateVoltage; CRT grid/focusing limits retained as parameters rather than mis-promoted as ordinary screen-grid data.

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

1968 General Electric Co

Published operating points and test conditions from this source.

SECTION 1

Cathode Ray

Other

Maximum Anode Voltage
22000 V
Maximum Grid No. 2 Voltage
100 V
Anode Voltage
18000 V
Typical
Heater Voltage
6.3 V
Heater Current
600 mA