19CUP4 — Rectangular Glass Television Picture Tube

The 19CUP4 is a 19-inch, direct-view rectangular glass television picture tube designed with a 114-degree diagonal deflection angle. It features an aluminized screen, a spherical faceplate, a non-ion trap gun, internal shielding, electrostatic focusing, and magnetic deflection. As a "HiGm" (high transconductance) tube, it is specifically optimized for cathode drive service under low Grid #2 voltage conditions. The physical design incorporates a short tube base with straight-through leads oriented by an indexing lug.

Mechanical and Optical Specifications

Physical Dimensions and Bulb Structure

The 19CUP4 is constructed using the J149A2 glass bulb. Its physical dimensions are characterized by the following measurements:

• Overall Length: 11 5/8 inches (with a tolerance of +1/4 and -3/16 inches)
• Neck Length: 4 3/16 inches (with a tolerance of +1/8 and -1/16 inches)
• Greatest Bulb Dimensions:
  • Diagonal: 18 5/8 ± 1/8 inches
  • Width: 16 13/32 ± 1/8 inches
  • Height: 13 11/32 ± 1/8 inches

The minimum useful screen dimensions provide a total viewing area of 172 square inches, defined by:

• Diagonal: 17 9/16 inches
• Width: 15 1/8 inches
• Height: 12 inches

Optical Characteristics

The screen utilizes an aluminized P4 phosphor, which produces a white fluorescent color with medium-short persistence. The spherical faceplate has a light transmission of approximately 77% at the center.

Base and Electrical Connections

The tube is equipped with a B7-208 base and uses an 8HR basing configuration. The high-voltage anode connection is made via a J1-21 contact, which aligns with Pin #4 within a tolerance of ±30 degrees.

Electrical Characteristics and Deflection

Deflection Angles

The 19CUP4 employs magnetic deflection with the following approximate angles:

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

Direct Interelectrode Capacitances

The approximate capacitances of the tube's electrodes are:

• Cathode to all other electrodes: 4.0 pF
• Grid #1 to all other electrodes: 6.0 pF
• External conductive coating capacitance: 1300 pF minimum to 1700 pF maximum

Heater Ratings

The heater is designed for a nominal voltage of 6.3 V and draws a current of 0.45 A ± 5% at this voltage. The heater warm-up time is rated at 11 seconds. This warm-up time is defined as the time required to reach 80% of the rated heater voltage when 4 times the rated voltage is applied in series with a resistance equal to 3 times the rated voltage divided by the rated current.

Cathode Drive Service Ratings

The 19CUP4 is rated under the Design Maximum system. All voltages are positive with respect to Grid #1 unless otherwise indicated.

Heater-Cathode Voltage Limits

The peak heater-cathode voltage limits vary depending on the polarity and operating state:

• Heater negative with respect to cathode:
  • During the warm-up period (less than or equal to 15 seconds): 450 V Max
  • After the equipment warm-up period: 200 V Max
• Heater positive with respect to cathode: 200 V Max

Typical Operating Conditions

For typical cathode drive service, the operating conditions are established with voltages positive with respect to Grid #1:

• Anode Voltage: 16,000 V DC
• Grid #4 Voltage (Focus): -100 to +300 V DC
• Grid #2 Voltage: 65 V DC
• Cathode Voltage (for visual extinction of focused raster): +41 to +56 V DC

For the cutoff of an undeflected focus spot, the absolute bias value increases by approximately 4 V.

Technical Summary

The 19CUP4 is a 19-inch rectangular glass picture tube featuring a 114-degree diagonal deflection angle, electrostatic focusing, and magnetic deflection. Its "HiGm" electron gun is optimized for cathode drive service under low Grid #2 voltage conditions, requiring a typical Grid #2 potential of only 65 V DC and an anode potential of 16,000 V DC (up to a design maximum of 22,000 V DC). The tube utilizes an aluminized P4 phosphor screen for a white, medium-short persistence display, and is equipped with a B7-208 base and an 8HR basing arrangement.