17HP4C — Rectangular Glass Picture Tube

A rectangular glass cathode-ray picture tube featuring low-voltage electrostatic focus, 70-degree magnetic deflection, and an aluminized screen.

Overview

The 17HP4C is a rectangular glass picture tube designed for television receiver applications. It incorporates a low-voltage electrostatic focusing system and a 70-degree magnetic deflection angle. The tube features an aluminized screen with a P4-Sulfide Type phosphor and utilizes an electron gun design that requires no external ion-trap magnet.

Physical Construction and Optical Characteristics

The 17HP4C is constructed with a spherical Filterglass faceplate that provides approximately 74% light transmission, enhancing picture contrast under ambient illumination. The tube provides a projected screen area of 149 square inches.

Physically, the tube weighs approximately 18 lbs. Its dimensional specifications include:

• Overall Length: 19-3/16 inches ± 3/8 inch
• Neck Length: 7-1/2 inches ± 3/16 inch

The envelope features an external conductive coating of the Regular-Band type, with a grounding contact area located near the reference line. The electrical connection to the high-voltage anode is made via a Recessed Small Cavity cap (JEDEC No. J1-21). The base is a Small-Shell Duodecal 6-Pin configuration (JEDEC Group 4, No. B6-63), which conforms to the 12L bottom-view basing designation.

Electrical Connections and Pinout

The 12L basing arrangement provides the following connections, viewed from the bottom of the tube base:

Heater and Interelectrode Capacitances

The heater is designed for operation at a nominal voltage of 6.3 volts, drawing a current of 600 ± 30 mA. Under the design-maximum rating system, the allowable heater voltage range is 5.7 volts minimum to 6.9 volts maximum.

The direct interelectrode capacitances of the tube are:

• Cathode to all other electrodes: 5 pF
• Grid No. 1 to all other electrodes: 6 pF
• External conductive coating to anode: 750 pF minimum to 1500 pF maximum

The external conductive coating, when grounded, forms a capacitor with the internal anode coating, which serves as a filter capacitor for the high-voltage anode supply.

Maximum Ratings (Design-Maximum Values)

The following maximum and minimum limits are established under the Design-Maximum rating system. All voltages are positive with respect to the cathode unless otherwise specified:

Heater-Cathode Voltage Limits

The peak voltage between the heater and the cathode must be kept within the following limits:

• Heater negative with respect to cathode:
  • During the equipment warm-up period (not exceeding 15 seconds): 450 V maximum
  • After the equipment warm-up period: 200 V maximum
• Heater positive with respect to cathode:
  • Combined AC and DC voltage: 200 V maximum
  • DC component: 100 V maximum

Typical Operating Conditions (Grid-Drive Service)

In typical grid-drive service, where voltages are specified positive with respect to the cathode, the operating parameters are:

• Anode Voltage: 14,000 V
• Grid No. 4 Voltage: -56 to +310 V
• Grid No. 2 Voltage: 300 V
• Grid No. 1 Voltage (required for visual extinction of the focused raster): -28 to -72 V

The maximum allowable resistance in the Grid No. 1 circuit is 1.5 megohms.

Technical Summary

The 17HP4C is a rectangular glass picture tube featuring low-voltage electrostatic focusing and 70-degree magnetic deflection. It utilizes an aluminized P4-Sulfide phosphor screen with a spherical Filterglass faceplate offering 74% light transmission. Operating typically at an anode voltage of 14,000 V, it provides a projected screen area of 149 square inches. The tube's design eliminates the need for an external ion-trap magnet, simplifying receiver setup, while its standard 12L basing and Small-Shell Duodecal base facilitate integration into television chassis.