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16BNP4

Sixteen-inch P4 direct-view picture tube documented by National Video. Its anode operates over roughly 12–18 kV, typically about 15 kV, with an external conductive coating serving the high-voltage display structure.

Directly heatedCold cathodeCommon cathodeDissimilarSpecialized

Sections: 1
Base: B7-208
Socket code: NEOEIGHTAR7
Base pins: -
Nominal heater: 6.3 V / 600 mA

Description

16BNP4 — Electrostatic Focus Cathode Ray Tube

The 16BNP4 is a 16-inch, heavyweight cathode ray tube (CRT) featuring a 114-degree diagonal deflection angle and a short 4 3/8-inch neck length. Designed by the National Video Corporation, this tube is engineered for television display applications utilizing a cathode-drive configuration. It features an electrostatic focusing system, a straight electron gun that does not require an external ion trap magnet, and a low-voltage Grid No. 2 design.

Mechanical and Optical Specifications

The 16BNP4 is constructed with a glass bulb designated as J125-C1 (or equivalent). The physical dimensions of the tube are tightly controlled, with key measurements specified at the mold-match line:

Overall Length: 10 1/2 inches (with a tolerance of +5/16 inch)
Neck Length: 4 3/8 inches (with a tolerance of ±1/8 inch)
Greatest Diagonal Dimension: 15 5/8 inches (with a tolerance of ±1/8 inch)
Greatest Width: 13 23/32 inches (with a tolerance of ±1/8 inch)
Greatest Height: 11 3/32 inches (with a tolerance of ±1/8 inch)

Screen and Optical Characteristics

The tube features an aluminized JEDEC P4 phosphor screen, which provides a minimum useful projected screen area of 125 square inches. The minimum useful projected screen dimensions are:

Diagonal: 14 7/8 inches
Horizontal Axis: 12 15/16 inches
Vertical Axis: 10 1/4 inches

The light transmittance at the center of the screen is approximately 78 percent.

Deflection and Alignment

The tube is designed for wide-angle magnetic deflection, with approximate deflection angles as follows:

Horizontal: 103 degrees
Vertical: 87 degrees
Diagonal: 114 degrees

The high-voltage anode connection is made via a JEDEC J1-21 recessed small cavity cap (ultor terminal), which connects internally to Grid No. 3, Grid No. 5, and the collector. This terminal is located on the same side of the bulb as Pin No. 4, with an angular alignment tolerance of ±30 degrees relative to the plane passing through the tube axis and Pin No. 4.

Electrical Ratings and Operating Conditions

The electrical ratings for the 16BNP4 are established under the Design Maximum System. Unless otherwise specified, all voltage values are positive and measured with respect to Grid No. 1.

Design Maximum Ratings

Anode Voltage: 18,000 Volts maximum, 12,000 Volts minimum
Grid No. 4 (Focusing Electrode) Voltage: -500 to +1100 Volts
Grid No. 2 Voltage: 25 Volts minimum, 60 Volts maximum
Cathode Voltage:
- DC Positive Value: 100 Volts maximum
- Peak Positive Value: 150 Volts maximum
- DC Negative Value: 0 Volts maximum
- Peak Negative Value: 2 Volts maximum
Heater Voltage: 5.8 Volts minimum, 6.9 Volts maximum
Heater-Cathode Voltage:
- Heater negative with respect to cathode (during warm-up, ≤ 15 seconds): 450 Volts maximum
- Heater negative with respect to cathode (after warm-up): 200 Volts maximum
- Heater positive with respect to cathode: 200 Volts maximum

Typical Operating Conditions (Cathode Drive Service)

In typical cathode-drive applications, the operating voltages are referenced to Grid No. 1:

Anode Voltage: 15,000 Volts DC
Grid No. 4 Voltage: 250 Volts DC (individual tubes will achieve satisfactory focus at some value between 0 and 400 Volts DC)
Grid No. 2 Voltage: 50 Volts DC
Cathode Voltage (for visual extinction of focused raster): 35 to 55 Volts DC

These typical operating conditions are specified with the combined Grid No. 1 bias voltage and video-signal voltage adjusted to produce an anode current of 100 microamperes on a 12 15/16" x 10 1/4" pattern (such as that from an RCA 2F21 Monoscope or equivalent).

Direct Interelectrode Capacitances

Cathode to all other electrodes: approximately 5 pF
Grid No. 1 to all other electrodes: approximately 6 pF
External conductive coating to anode: 1000 pF minimum, 1500 pF maximum

Pinout, Basing, and Installation Requirements

The 16BNP4 utilizes a JEDEC 8HR base with a B7-208 basing arrangement. The pin connections, viewed from the bottom of the tube base, are as follows:

Pin Number	Connection
Pin 1	Heater
Pin 2	Grid No. 1
Pin 3	Grid No. 2
Pin 4	Grid No. 4 (Focusing Electrode)
Pin 6	Grid No. 1
Pin 7	Cathode
Pin 8	Heater
Cap	Ultor (Grid No. 3, Grid No. 5, Collector)
C	External Conductive Coating

Installation and Handling Guidelines

Socket Mounting: The socket for the 8HR base must not be rigidly mounted. It should be connected via flexible leads and allowed to move freely to prevent the circuit wiring from exerting lateral strain on the base pins. The bottom circumference of the base wafer is designed to fit within a 1 3/4-inch diameter circle concentric with the bulb axis.
Reference Line: The reference line is determined using a JEDEC No. G-126 reference-line gauge. When the tube neck is inserted through the flared end of the gauge and seated, the reference line is defined by the intersection of Plane CC' of the gauge with the glass funnel.
Grounding: The external conductive coating must be grounded to ensure proper operation and safety.
Cleaning: The area of the external conductive coating and transparent insulating coating should be cleaned only by wiping with a soft, dry, lint-free cloth.
Grid No. 1 Circuit Resistance: The maximum allowable resistance in the Grid No. 1 circuit is 1.5 Megohms.
Heater Characteristics: The heater operates at a nominal voltage of 6.3 Volts with a current of 600 ± 30 mA. The heater has a controlled warm-up time of 11 seconds.

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: B7-208
Socket code: NEOEIGHTAR7
Base pins: -
Nominal heater voltage: 6.3 V
Nominal heater current: 600 mA
Parallel heater voltage: -
Parallel heater current: -
Series capable: No

B7-208 - 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

No fixed ratings are recorded for this section.

CRT maximum anode voltage 18000 V; CRT-specific electrode ratings retained in parameter table.

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

1956 National Video

Published operating points and test conditions from this source.

SECTION 1

Cathode Ray

Other

The [1]
16
The 16BNP4 is a 16"-1149 heavyweight cathode ray tube with a 4 3/8"
The [2]
16
The 16BNP4 is a 16"-1149 heavyweight cathode ray tube with a 4 3/8"
The [3]
-1149
The 16BNP4 is a 16"-1149 heavyweight cathode ray tube with a 4 3/8"
The [4]
4
The 16BNP4 is a 16"-1149 heavyweight cathode ray tube with a 4 3/8"
The [5]
3
The 16BNP4 is a 16"-1149 heavyweight cathode ray tube with a 4 3/8"
The [6]
8
The 16BNP4 is a 16"-1149 heavyweight cathode ray tube with a 4 3/8"
straight gun which requires no ion trap, and
50 V
straight gun which requires no ion trap, and 50 volt G2 for cathode
Grid # [1]
1 pF
Grid #1 to all other electrodes, approximate 5 uuf
Grid # [2]
5 pF
Grid #1 to all other electrodes, approximate 5 uuf
External Conductive Coating to Anode
1500 pF
External Conductive Coating to Anode 1500 Max. uuf
Heater Current at [1]
6.3 V
Heater Current at 6.3 Volts 600 + 30 Ma
Heater Current at [2]
600 V
Heater Current at 6.3 Volts 600 + 30 Ma
Heater Current at [3]
30 V
Heater Current at 6.3 Volts 600 + 30 Ma
Heater Warm-up Time
11
Heater Warm-up Time 11 Seconds
Light Transmittance at Center, Approximate
78
Light Transmittance at Center, Approximate 78 Percent
and measured with respect to Grid #
1
and measured with respect to Grid #1.
Maximum Anode Voltage
18000 V
Maximum Anode Voltage 18,000 Volts
Minimum Anode Voltage
12000 V
Minimum Anode Voltage 12,000 Volts
Maximum Grid # [1]
4 V
Maximum Grid #4 (Focusing Electrode) Voltage +1100 -500
Maximum Grid # [2]
1100 V
Maximum Grid #4 (Focusing Electrode) Voltage +1100 -500
Maximum Grid # [3]
-500 V
Maximum Grid #4 (Focusing Electrode) Voltage +1100 -500
Maximum Grid # [1]
2 V
Maximum Grid #2 Voltage 60 Volts
Maximum Grid # [2]
60 V
Maximum Grid #2 Voltage 60 Volts
Minimum Grid # [1]
2 V
Minimum Grid #2 Voltage 25 Volts
Minimum Grid # [2]
25 V
Minimum Grid #2 Voltage 25 Volts
Maximum Heater Voltage
6.9 V
Maximum Heater Voltage 6.9 Volts
Minimum Heater Voltage
5.8 V
Minimum Heater Voltage 5.8 Volts
During warm-up period not to exceed [1]
15 V
During warm-up period not to exceed 15 seconds 450 Volts
During warm-up period not to exceed [2]
450 V
During warm-up period not to exceed 15 seconds 450 Volts
After equipment warm-up period
200 V
After equipment warm-up period 200 Volts
Heater positive with respect to cathode
200 V
Heater positive with respect to cathode 200 Volts
positive with respect to Grid #
1
positive with respect to Grid #1,
Anode Voltage
15000 V
Anode Voltage 15,000 Volts DC
Grid #
4 V
Grid #4 Voltage (Focusing Electrode)
Grid # [1]
2 V
Grid #2 Voltage 50 Volts DC
Grid # [2]
50 V
Grid #2 Voltage 50 Volts DC
Cathode Voltage (Note [1]
1 V
Cathode Voltage (Note 1) 35 to 55 Volts DC
Cathode Voltage (Note [2]
35 V
Cathode Voltage (Note 1) 35 to 55 Volts DC
Cathode Voltage (Note [3]
55 V
Cathode Voltage (Note 1) 35 to 55 Volts DC
Maximum Grid # [1]
1
Maximum Grid #1 Circuit Resistance 1.5 Megohms
Maximum Grid # [2]
1.5
Maximum Grid #1 Circuit Resistance 1.5 Megohms
Pin [1]
1
Pin 1 Heater Pin 6 Grid No, 1
Pin [2]
6
Pin 1 Heater Pin 6 Grid No, 1
Pin [3]
1
Pin 1 Heater Pin 6 Grid No, 1
Pin [1]
2
Pin 2 Grid No. 1 Pin 7 Cathode
Pin [2]
1
Pin 2 Grid No. 1 Pin 7 Cathode
Pin [3]
7
Pin 2 Grid No. 1 Pin 7 Cathode
Pin [1]
3
Pin 3 Grid No. 2 Pin 8 Heater
Pin [2]
2
Pin 3 Grid No. 2 Pin 8 Heater
Pin [3]
8
Pin 3 Grid No. 2 Pin 8 Heater
Published value
20
20 ® IPINSGRIDNO.I (NOTE5
Published value
1
1. Visual extinction of focused raster,
Published value [1]
2 V
2. With the combined grid #1 bias voltage and video-signal voltage
Published value [2]
1 V
2. With the combined grid #1 bias voltage and video-signal voltage
adjusted to give an anode current of
100
adjusted to give an anode current of 100 microanmperes on a
Published value
3
3. Individual tubes will have satisfactory focus at some value