19CYP4

The 19CYP4 is a 19-inch cathode ray tube designed with a 114-degree diagonal deflection angle. It features electrostatic focusing and magnetic deflection, utilizing a straight electron gun that does not require an ion trap. The tube is equipped with a metal-backed, aluminized screen containing P4 phosphor to provide a bright, high-contrast display.

Physical and Mechanical Characteristics

The 19CYP4 is constructed with a glass bulb designated as EIA J-149-A1. It features a JEDEC J1-21 Ultor recessed small cavity cap for high-voltage connection, which is aligned with pin position 4 within a tolerance of ±30 degrees. The tube utilizes a JEDEC B7-208 Small Button Neoeightar 7-pin base with an 8HR basing configuration.

Dimensions and Screen Area

The physical dimensions of the tube are highly compact relative to its screen size:

• Overall Length: 10 7/8 ± 1/4 inches
• Neck Length: 3 5/8 ± 1/8 inches
• Greatest Diagonal: 18 5/8 ± 1/8 inches
• Greatest Width: 16 13/32 ± 1/8 inches
• Greatest Height: 13 11/32 ± 1/8 inches

The projected minimum useful screen dimensions are:

• Diagonal: 17 9/16 inches
• Horizontal Axis: 15 1/8 inches
• Vertical Axis: 12 inches
• Total Useful Area: 172 square inches

Optical Properties

The screen uses a P4-Aluminized phosphor. The light transmittance at the center of the faceplate is approximately 78%.

Electrical Connections and Pinout

The 19CYP4 uses the JEDEC 8HR basing arrangement. The pin assignments, viewed from the bottom of the base, are as follows:

Note that Grid No. 1 is connected to both Pin 2 and Pin 6.

Heater and Capacitance Ratings

The heater is designed for a nominal voltage of 6.3 V, with a Design-Maximum range of 5.7 V to 6.9 V. Under nominal operation, the heater draws a current of 600 ± 30 mA. The heater has a controlled warm-up time of 11 seconds.

Direct Interelectrode Capacitances

• Cathode to all other electrodes: Approximately 5 µµF
• Grid No. 1 to all other electrodes: Approximately 6 µµF
• External conductive coating to Anode: 1,000 µµF minimum to 1,500 µµF maximum

Operating Ratings and Typical Conditions

The 19CYP4 operates under the Design-Maximum System. The operating limits and typical grid-drive service conditions are detailed below.

Design-Maximum Ratings

• Anode Voltage: 15,000 V minimum to 23,000 V maximum
• Grid No. 4 (Focusing Electrode) Voltage: -500 V to +1000 V
• Grid No. 2 Voltage: 200 V minimum to 550 V maximum
• Grid No. 1 Voltage:
  • Maximum Negative DC Value: 154 V
  • Maximum Negative Peak Value: 220 V
  • Maximum Positive DC Value: 0 V
  • Maximum Positive Peak Value: 2 V
• Heater-Cathode Voltage:
  • Heater negative with respect to cathode (during warm-up, ≤ 15 seconds): 450 V maximum
  • Heater negative with respect to cathode (after warm-up): 200 V maximum
  • Heater positive with respect to cathode: 200 V maximum

Typical Operating Conditions (Grid Drive Service)

All operating voltages are specified as positive with respect to the cathode:

• Anode Voltage: 20,000 V DC
• Grid No. 4 Voltage: 0 to +400 V DC (satisfactory focus is achieved at some value within this range)
• Grid No. 2 Voltage: 400 V DC
• Grid No. 1 Voltage: -36 to -94 V DC (required range for visual extinction of the focused raster)

Maximum Circuit Values

The maximum resistance in the Grid No. 1 circuit must not exceed 1.5 Megohms.

Deflection and Safety Considerations

Deflection Angles

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

• Diagonal: 114°
• Horizontal: 102°
• Vertical: 85°

Safety Recommendations

Because of the high voltages and physical size of the tube, it is recommended to install a shatter-proof glass cover over the tube face. This cover serves a dual purpose, providing protection against potential implosions and offering shielding against x-ray radiation.