17CSP4 — Rectangular Glass Television Picture Tube

The 17CSP4 is a 17-inch direct-viewed, rectangular glass television picture tube. Designed for lightweight television receiver applications, it features a spherical faceplate made of gray filter glass, an aluminized screen, electrostatic focusing, and magnetic deflection. The tube operates without an ion trap and incorporates an external conductive coating.

Physical and Mechanical Construction

The 17CSP4 is constructed using a rectangular glass envelope designated as bulb J132 1/2 A1 or J132 1/2 B1. The complete assembly weighs approximately 10 pounds.

Screen and Faceplate Characteristics

The tube features a spherical faceplate composed of gray filter glass, which provides a light transmittance of approximately 77%. This filter glass improves picture contrast under ambient light conditions. The screen utilizes an aluminized P4 phosphor that produces white fluorescence with short-to-medium persistence.

Deflection and Coating

Deflection is achieved magnetically, with wide-angle coverage to minimize the overall depth of the television cabinet. The approximate deflection angles are:

• Horizontal: 105°
• Diagonal: 110°
• Vertical: 87°

An external conductive coating is applied to the envelope. This coating must be grounded during operation, as it forms a capacitor with the internal anode coating to assist in high-voltage filtering.

Heater, Base, and Electrical Connections

The 17CSP4 is equipped with an indirectly heated cathode. The heater is designed for reliable operation in series or parallel heater chains.

Heater Ratings

• Heater Voltage: 6.3 V
• Heater Current: 0.6 A ± 5%
• Heater Warm-up Time: 11 seconds

The heater warm-up time is defined as the time required for the heater voltage to reach 5.0 V when tested in a standard JETEC test circuit with an applied voltage of 25 V and a series resistance of 31.5 Ω.

Base and Pinout Configuration

The tube uses a B6-185 base with a 7FA basing arrangement. High-voltage connection to the anode is made via a recessed small cavity cap (J1-21) located on the bulb cone. The base pin No. 7 is aligned with the anode contact within an angular tolerance of 30°.

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

Electrical Characteristics and Capacitances

The interelectrode capacitances of the 17CSP4 are relatively low, which helps prevent unwanted circuit loading. The approximate capacitance values are:

• Cathode to all other electrodes: 5 µµF
• Grid No. 1 to all other electrodes: 6 µµF
• External conductive coating to anode: 900 µµF (minimum) to 1400 µµF (maximum)

Operating Conditions and Maximum Ratings

The 17CSP4 requires high operating voltages for proper focus and brightness. The tables below outline the typical operating conditions and the absolute maximum ratings.

Typical Operating Conditions

At a typical operating point, the tube is set up with the following parameters:

• Anode Voltage: 14,000 V dc
• Grid No. 4 Voltage (for Focus): -50 to +350 V dc
• Grid No. 2 Voltage: 300 V dc
• Grid No. 1 Voltage for Cutoff: -35 to -72 V dc (This range is required for the visual extinction of a focused raster. Extinction of a stationary focused spot requires approximately 5 V more negative bias.)

Absolute Maximum Ratings

These ratings are limiting values above which the serviceability and safety of the tube may be impaired:

Circuit Constraints

To ensure stable operation and prevent damage to the control grid, the Grid No. 1 circuit resistance must not exceed a maximum value of 1.5 MΩ.

Safety and Shielding Requirements

When operating the 17CSP4, safety precautions regarding X-ray radiation must be observed. If the tube is operated at anode voltages exceeding 16,000 V or the maximum rated anode voltage of 17,600 V (whichever is less), it may produce X-rays. Under these conditions, appropriate shielding must be installed in the television receiver to protect users from exposure.

Technical Summary

The 17CSP4 is a lightweight, 17-inch rectangular glass television picture tube utilizing electrostatic focus and wide-angle magnetic deflection (110° diagonal). It features an aluminized P4 white phosphor screen, a gray filter glass faceplate with 77% light transmittance, and an external conductive coating that must be grounded. Operating typically at an anode voltage of 14,000 V, the tube provides sharp focus via a dedicated Grid No. 4 focusing electrode (adjustable from -50 to +350 V). It uses a standard B6-185 base with a 7FA pinout and a 6.3 V, 0.6 A heater with a controlled 11-second warm-up time.