17DTP4 — Television Picture Tube

The 17DTP4 is a 17-inch direct-view rectangular glass television picture tube. It features a short neck design, electrostatic focusing, and 110-degree magnetic deflection. The tube incorporates an aluminized P4 phosphor screen, a gray filter glass faceplate, and does not require an ion trap. An external conductive coating is provided, which must be grounded during operation.

Mechanical and Optical Characteristics

The 17DTP4 is built using a rectangular glass envelope with a spherical faceplate. The faceplate is constructed of gray filter glass with a light transmittance of approximately 77%. The screen uses an aluminized P4 phosphor that produces white fluorescence with short-to-medium persistence.

Physical Dimensions and Envelope

The tube has a neck diameter of 1 1/8 inches. Depending on the specific manufacturing variant, the bulb is designated as J132 1/4-A, J132 1/4-B, J132 1/2-A, or J132 1/2-B. The physical dimensions and mechanical specifications include:

• Minimum Useful Screen Dimensions:
  • Height: 11 11/16 inches
  • Width: 14 3/4 inches
  • Diagonal: 15 5/8 to 15 3/4 inches
  • Area: 155 square inches
• Neck Length: 3 3/8 ± 1/8 inches or 3 5/8 ± 1/8 inches
• Overall Length: 10 3/4 ± 1/4 inches
• Weight: Approximately 10 pounds
• Bulb Contact: Recessed small cavity cap (J1-21)
• Base: B7-208

Heater Ratings and Warm-up Time

The 17DTP4 is equipped with a heater designed for series or parallel operation in television receivers.

The heater warm-up time is defined as the time required to reach 80% of the rated heater voltage when four times the rated voltage is applied in series with a resistance equal to three times the rated voltage divided by the rated current.

Basing and Electrical Connections

The tube uses the 8HR basing configuration with a B7-208 base. The electrical connections are assigned as follows:

The anode connection is made via a recessed small cavity cap (J1-21) located on the bulb. This anode contact aligns on the same side as pin 4, within 30 degrees of the horizontal centerline.

Direct Interelectrode Capacitances

The direct interelectrode capacitances of the 17DTP4 are approximately:

• Cathode to all other electrodes: 5 µµf
• Grid No. 1 to all other electrodes: 6 µµf
• External conductive coating to anode:
  • Maximum: 1500 µµf
  • Minimum: 1000 µµf

The external conductive coating must be grounded to utilize this capacitance as a filter capacitor for the high-voltage anode supply.

Electrical Ratings and Operating Conditions

The ratings of the 17DTP4 are defined under the Design-Maximum system for grid-drive service.

Design-Maximum Ratings

These values represent the absolute limits within which the tube must be operated:

• Anode Voltage: 17,600 V dc
• Grid No. 4 Voltage (Focusing Electrode): -550 to +1100 V dc
• Grid No. 2 Voltage: 550 V dc
• Grid No. 1 Voltage:
  • Negative Bias Value: 155 V dc
  • Negative Peak Value: 220 V
  • Positive Bias Value: 0 V dc
  • Positive Peak Value: 2 V
• Peak Heater-Cathode Voltage:
  • Heater negative with respect to cathode during warm-up (≤ 15 s): 450 V
  • Heater negative with respect to cathode after warm-up: 200 V
  • Heater positive with respect to cathode: 200 V

Typical Operating Conditions (Grid Drive Service)

Under typical operating conditions, the tube is set up with the following parameters:

• Anode Voltage: 14,000 V dc
• Grid No. 4 Voltage for Focus: 0 to 400 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 visual extinction of a focused raster. Extinction of a stationary focused spot requires approximately 5 V more negative bias.)

Circuit Values

• Grid No. 1 Circuit Resistance: 1.5 Megohms maximum

Operating Considerations and Safety

The external conductive coating must be connected to a reliable electrical ground. Additionally, because the tube operates at high voltages, X-ray shielding may be necessary if the anode is operated above the maximum rated anode voltage or 16,000 volts, whichever is less.

Technical Summary

The 17DTP4 is a 17-inch rectangular glass television picture tube featuring electrostatic focus and 110-degree magnetic deflection. It operates with a 6.3 V, 0.60 A heater and uses the 8HR basing configuration. With an aluminized P4 phosphor screen, a gray filter glass faceplate, and an external conductive coating, it is designed for grid-drive television receiver applications. Its design-maximum anode voltage rating is 17,600 V dc, and it typically operates at 14,000 V dc with a focusing voltage range of 0 to 400 V dc.