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21CBP4A

Large P4 monochrome television picture tube documented for high-voltage direct-view service, using magnetic deflection and manufacturer-specified focusing and beam-control arrangements for type 21CBP4A.

Directly heatedCold cathodeCommon cathodeDissimilarSpecialized

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

Description

The Westinghouse 21CBP4A is a 21-inch 90-degree aluminized P4 CRT with higher 20 kV maximum anode rating and no-ion-trap gun.

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: 12L
Socket code: DUODECAL5
Base pins: -
Nominal heater voltage: 6.3 V
Nominal heater current: 600 mA
Parallel heater voltage: -
Parallel heater current: -
Series capable: No

12L - 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

Cathode-ray electron-gun/screen system; anode/ultor maximum promoted to MaxPlateVoltage when explicitly published. Explicit X-ray warning/precaution or X-radiation characteristic is present in the supplied source.

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 Sylvania Electronic Tubes Vol3

Published operating points and test conditions from this source.

SECTION 1

Cathode Ray

Characteristic

Heater Voltage
6.3 V
Heater Current
600 mA
FocusingMethod
Electrostatic
DeflectionMethod
Magnetic
Phosphor
Aluminized P4 white
DeflectionAngles
large-angle magnetic
Cathode To All Capacitance
5 pF
Grid1 To All Capacitance
6 pF
ExternalConductiveCoatingToAnodeCapacitanceMaximum
2500 pF
ExternalConductiveCoatingToAnodeCapacitanceMinimum
2000 pF

Other

AnodeVoltageMaximum
22000 V
AnodeVoltageMinimum
10000 V
FocusingElectrodeVoltageRangeMaximum
-550 to +1100 V
Grid2VoltageMaximum
550 V
Grid2VoltageMinimum
200 V
Grid1NegativeBiasMagnitudeMaximum
155 V
Grid1PositivePeakVoltageMaximum
2 V
HeaterCathodeVoltageMaximum
450 V
Warmup<=15s;HeaterNegative
HeaterCathodeVoltageMaximum
200 V
AfterWarmup
HeaterCathodeVoltageMaximum
200 V
HeaterPositive
Anode Voltage
16000 V
FocusingElectrodeVoltage
-50 to +350 V
Grid1VoltageForCutoff
-28 to -72 V
Grid1CircuitResistanceMaximum
1.5 Mohm

Data set 02

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
600 mA
Heater Warm-up Time
11 s
Focusing Method
Low Voltage Electrostatic text
Deflection Method
Magnetic text
Horizontal Deflection Angle
85 deg
Approximate
Vertical Deflection Angle
68 deg
Approximate
Diagonal Deflection Angle
90 deg
Approximate
Phosphor
Aluminized P4 text
Fluorescence
White text
Persistence
Short to Medium text
Light Transmittance
73 percent
Approximate
Cathode-to-All Capacitance
5 pF
Approximate
Grid1-to-All Capacitance
6 pF
Approximate
External Coating-to-Anode Capacitance Minimum
2000 pF
External Coating-to-Anode Capacitance Maximum
2500 pF

Other

Maximum Anode Voltage
20000 V
Minimum Anode Voltage
11000 V
Maximum Focus Electrode Voltage Positive
1100 V
Grid4
Maximum Focus Electrode Voltage Negative
-550 V
Grid4
Maximum Grid2 Voltage
500 V
Minimum Grid2 Voltage
200 V
Maximum Heater-Cathode Voltage During Warmup
450 V
Duration<=15s
Maximum Heater-Cathode Voltage After Warmup
180 V
Typical Anode Voltage
16000 V
CathodeDrive
Typical Focus Voltage Minimum
0 V
Grid4
Typical Focus Voltage Maximum
400 V
Grid4
Typical Grid2 Voltage
300 V
CathodeDrive
Cathode Voltage for Raster Cutoff Minimum
28 V
CathodeDrive
Cathode Voltage for Raster Cutoff Maximum
72 V
CathodeDrive
Maximum Grid1 Circuit Resistance
1.5 Mohm

Data set 03

1971 RCA HB3 Binder 1 of 7

Published operating points and test conditions from this source.

SECTION 1

Cathode Ray

Other

Heater Voltage
6.3 V
Nominal heater voltage
Heater Current
600 mA
Nominal heater current
Phosphor
P4
Published phosphor designation
Heater Current at
10 mA
Heater Current at 6.3 volts 600 t 10% ma
External conductive coating to ultor
12500 pF
External conductive coating to ultor. 12500 max. pF
Projected Area of Screen
262 sq in
Projected Area of Screen 262 sq. in.
ULTOR VOLTAGE
22000 V
ULTOR VOLTAGE 22000 max. volts
GRID-No.2 VOLTAGE
550 V
GRID-No.2 VOLTAGE 550 max. volts
After equipment warm-up period
200 V
After equipment warm-up period. 200 max. volts
respect to cathode
200 V
respect to cathode 200 max. volts
With ultor voltage of ib000 volts
0 V
With ultor voltage of ib000 volts
and grid-No.2 voltage o} goo volts
2 V
and grid-No.2 voltage o} goo volts
Grid-No.4 Voltage for focus
0 to 450 V
Grid-No.4 Voltage for focus 0 to 450 volts
extinction of focused raster
-28 to -72 V
extinction of focused raster -28 to -72 volts
Grid-No.l~ircuit Resistance
1.5 MΩ
Grid-No.l~ircuit Resistance 1.5 max. megohms

Construction

Focusing Method
Electrostatic
Published focusing method
Deflection Method
Magnetic
Published deflection method

Characteristic

LOW-VOLTAGE ELECTROSTATIC FOCUS
90 deg
LOW-VOLTAGE ELECTROSTATIC FOCUS 90° MAGNETIC DEFLECTION
Grid No.l to all other electrodes
6 pF
Grid No.l to all other electrodes 6 pF
Cathode to all other electrodes
5 pF
Cathode to all other electrodes 5 pF