17DCP4 — Electrostatic-Focus Television Picture Tube

The 17DCP4 is a 17-inch, direct-viewed, rectangular glass television picture tube. It features electrostatic focusing, magnetic deflection, and an aluminized screen, designed for television receiver applications without the need for an external ion trap magnet.

Construction and Screen Characteristics

The 17DCP4 is constructed with a rectangular glass bulb (J133F or J133G) and a spherical faceplate made of gray filter glass. This faceplate provides approximately 74% light transmittance, which helps improve picture contrast under ambient light.

The screen utilizes an aluminized P4 phosphor that produces a white fluorescence. This phosphor is characterized by short to medium persistence, making it suitable for displaying moving television images without objectionable trailing.

Deflection is accomplished magnetically, with nominal deflection angles of:

• Horizontal deflection: 85°
• Diagonal deflection: 90°

The tube incorporates an external conductive coating that must be grounded. This coating, in conjunction with the internal anode, forms a capacitor that assists in high-voltage filtering. The external coating contact area is 2" x 2" and is located 90° counterclockwise from the anode contact (when viewed from the base). The anode contact itself is a recessed small cavity cap (J1-21) that aligns with pin 6 ± 30°.

Physical Dimensions and Weight

• Weight: Approximately 13 pounds
• Minimum Useful Screen Dimensions: 14 5/16 x 11 1/8 inches
• Minimum Useful Screen Area: 149 square inches

Electrical Connections and Pinout

The 17DCP4 uses a small shell duodecal 6-pin base (B6-63) with a 12L basing arrangement. The electrical connections are assigned as follows:

Heater Characteristics

The heater is designed for a nominal voltage of 6.3 V and draws a current of 0.3 ± 5% A (300 mA).

The heater warm-up time is rated at 11 seconds. This warm-up time is specifically defined as the time required for the heater voltage to reach 80% of its rated value when four times the rated heater voltage is applied in series with an external resistance equal to three times the rated voltage divided by the rated current.

Direct Interelectrode Capacitances

The approximate capacitances of the tube's electrodes are:

• Cathode to all other electrodes: 5 µµf
• Grid No. 1 to all other electrodes: 6 µµf
• External conductive coating to anode: 1000 µµf (minimum) to 1500 µµf (maximum)

Typical Operating Conditions

Under typical operating conditions, the electrostatic focusing electrode (Grid No. 4) is adjusted to focus the electron beam onto the screen. The typical operating parameters are:

• Anode Voltage: 14,000 Volts dc
• Grid No. 4 Voltage (Focusing Electrode): -50 to +300 Volts dc
• Grid No. 2 Voltage: 300 Volts dc
• Grid No. 1 Voltage for Cutoff: -35 to -72 Volts dc

The Grid No. 1 voltage range specified for cutoff is the value required to achieve visual extinction of a focused raster. To achieve complete extinction of a stationary focused spot, the Grid No. 1 bias must be made approximately 5 Volts more negative.

Circuit Constraints

To ensure stable operation and prevent damage to the tube, the maximum Grid No. 1 circuit resistance must not exceed 1.5 Megohms.

Absolute Maximum Ratings

The following absolute maximum values must not be exceeded under any condition of operation:

Heater-Cathode Voltage Limits

The potential difference between the heater and the cathode is restricted to prevent insulation breakdown:

• 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

Safety and X-ray Radiation

When operating the 17DCP4 at high voltages, safety precautions regarding X-ray radiation must be observed. Appropriate shielding may be necessary to protect users if the tube is operated above 16,000 Volts or above its maximum rated anode voltage (17,600 Volts), whichever of these two values is less.