19ALP4 — Television Picture Tube

The 19ALP4 is a rectangular glass television picture tube designed for cathode drive service. It features a 114-degree magnetic deflection system, low-voltage electrostatic focusing, and an aluminized P4 phosphor screen. The tube incorporates a gray filter glass spherical faceplate with a minimum useful projected screen area of 172 square inches (measuring 12 inches by 15-1/8 inches). It is constructed with a short neck, requires no ion trap, and includes an external conductive coating that acts as a supplementary filter capacitor when grounded.

Mechanical Specifications and Construction

The 19ALP4 is built using a J149 glass bulb and has the following physical dimensions:

• Overall Length: 11-3/8 ± 1/4 inches
• Neck Length: 4-1/8 ± 1/8 inches
• Neck Diameter: 1.125 inches nominal, with a maximum of 1.168 inches at the splice
• Greatest Dimensions: Diagonal 18-5/8 ± 1/8 inches, Width 16-13/32 ± 1/8 inches, Height 13-11/32 ± 1/8 inches
• Minimum Useful Screen Dimensions: Diagonal 17-9/16 inches, Horizontal 15-1/8 inches, Vertical 12 inches
• Weight: 13-1/2 lbs

The tube uses a B7-208 wafer base, which has its perimeter within a 1-3/4 inch diameter circle concentric with the tube axis. The mating socket must have flexible leads to prevent lateral strains on the base pins. The anode terminal is a J1-21 recessed cavity cap, which has an angular alignment tolerance of ±30 degrees relative to pin 4.

Heater and Electrical Characteristics

The 19ALP4 features an indirectly heated cathode with the following heater specifications:

• Heater Voltage: 6.3 V
• Heater Current: 300 ± 5% mA
• Heater Warm-up Time: 18 seconds (defined as the time required to reach 80% of rated voltage under specified test conditions where 4 times the rated voltage is applied in series with a resistance equal to 3 times the rated voltage divided by the rated current)

Direct Interelectrode Capacitances

• Cathode to all other electrodes: approximately 5 pF
• Grid 1 to all other electrodes: approximately 6 pF
• External conductive coating to anode: 1000 pF (minimum) to 1500 pF (maximum)

The external conductive coating must be grounded to function as a supplementary filter capacitor.

Pinout and Basing (8HR)

The 19ALP4 uses the 8HR basing configuration. The pin connections are as follows:

• Pin 1: Heater (H)
• Pin 2: Grid 1 (G1)
• Pin 3: Grid 2 (G2)
• Pin 4: Grid 4 (G4) - Focusing Electrode
• Pin 6: Grid 1 (G1)
• Pin 7: Cathode (K)
• Pin 8: Heater (H)
• Cap: Anode (A)

Note that Grid 1 is connected to both Pin 2 and Pin 6.

Design Maximum Ratings

The following design maximum ratings are specified with voltages positive with respect to Grid 1, unless otherwise noted:

• Anode Voltage: 12,000 V (minimum) to 22,000 V (maximum). Operation below 12,000 V is not recommended due to a decrease in picture brilliance and definition.
• Grid 4 Voltage (Focusing Electrode): -550 V (minimum) to +1100 V (maximum)
• Grid 2 Voltage: 700 V (maximum)
• Cathode Voltage:
  • Maximum Negative Value: 0 V DC
  • Maximum Negative Peak Value: 2 V
  • Maximum Positive Value: 154 V DC
  • Maximum Positive Peak Value: 220 V
• Maximum Heater-Cathode Voltage:
  • Heater negative with respect to cathode during warm-up (≤ 45 seconds): 450 V
  • Heater negative with respect to cathode after equipment warm-up: 200 V
  • Heater positive with respect to cathode: 200 V

Typical Operating Conditions (Cathode Drive Service)

Under typical operating conditions in cathode drive service, the voltages are specified positive with respect to Grid 1:

• Anode Voltage: 14,000 V DC
• Grid 4 Voltage (Focusing Electrode): 0 to 400 V DC
• Grid 2 Voltage: 500 V DC
• Cathode Voltage for Raster Cutoff: 45 to 95 V DC

Limiting Circuit Values

To prevent damage to the tube, the following circuit resistance limits must be observed:

• Maximum Grid 1 Circuit Resistance: 1.5 Megohms
• Minimum Grid 2 and Grid 4 Circuit Resistance: 10,000 Ohms (protective resistance is advised in these circuits)

Deflection and Alignment Notes

The 19ALP4 utilizes magnetic deflection with the following approximate angles:

• Diagonal Deflection: 114 degrees
• Horizontal Deflection: 103 degrees
• Vertical Deflection: 86 degrees

A permanent magnet (PM) centering magnet providing a field of 0 to 8 gauss may be used. This magnet should extend no more than 2-1/8 inches from the Yoke Reference Line, as determined by JEDEC Reference-Line Gauge No. 126.

Safety and X-Ray Warning

When operating the 19ALP4, safety precautions regarding X-ray radiation must be observed. Operation with anode voltages in excess of 16,000 V may require shielding to limit the radiation of very soft X-rays.

Technical Summary

The 19ALP4 is a 114-degree magnetic deflection television picture tube featuring a rectangular glass envelope, low-voltage electrostatic focusing, and an aluminized P4 phosphor screen. Operating at a nominal heater voltage of 6.3 V and 300 mA, it is designed for cathode drive service with typical anode voltages around 14,000 V. The tube utilizes an 8HR basing configuration on a B7-208 wafer base and requires protective circuit resistances on Grids 2 and 4 to prevent damage. Proper grounding of its external conductive coating is necessary to utilize its supplementary filtering capacitance.