17JR6 — Beam Power Tube

A Novar-type beam power tube designed for horizontal- and vertical-deflection amplifier service in television receivers.

Overview

The 17JR6 is a beam power tube utilizing a Novar envelope and base. It is primarily designed for horizontal-deflection amplifier service in low B+ black-and-white television receivers, as well as vertical-deflection amplifier service. The 17JR6 is electrically identical to the 6JR6, 22JR6, and 33JR6 vacuum tubes, differing only in its heater ratings and characteristics.

Construction, Heater, and Pinout

The 17JR6 is constructed in a Novar glass envelope and requires a standard 9-contact Novar socket. It features a unipotential coated cathode and a heater designed for series-string or parallel operation.

Heater Ratings

• Heater Voltage (AC/DC): 16.8 V
• Heater Current: 0.6 A (with a tolerance of 0.600 ± 0.040 A)
• Average Heater Warm-up Time: 11 seconds
• Heater-Cathode Voltage:
  • Peak value: ±200 V maximum
  • Average value: 100 V maximum

Pinout and Base Connections

The tube utilizes the 9QU base pinout. There are two documented configurations for the connections of pins 8 and 9:

• Configuration A:
  • Pin 1: Grid No. 1
  • Pin 2: Grid No. 2
  • Pin 3: Cathode
  • Pin 4: Heater
  • Pin 5: Heater
  • Pin 6: Grid No. 3
  • Pin 7: Grid No. 2
  • Pin 8: Plate
  • Pin 9: Internal Connection (IC)
• Configuration B:
  • Pin 1: Grid No. 1
  • Pin 2: Grid No. 2
  • Pin 3: Cathode
  • Pin 4: Heater
  • Pin 5: Heater
  • Pin 6: Grid No. 3
  • Pin 7: Grid No. 2
  • Pin 8: Internal Connection (IC)
  • Pin 9: Plate

Interelectrode Capacitances

The approximate direct interelectrode capacitances of the 17JR6 are:

• Grid No. 1 to Plate: 0.7 pF
• Grid No. 1 to Cathode, Heater, Grid No. 2, and Grid No. 3: 22 pF
• Plate to Cathode, Heater, Grid No. 2, and Grid No. 3: 9 pF

Typical Characteristics and Operating Points

The 17JR6 can be operated in either triode or pentode configurations. Typical Class A/Class A1 characteristics are documented under specific operating conditions.

Triode Connection

When operated as a triode (with Grid No. 2 connected to the plate and Grid No. 3 connected to the cathode at the socket):

• Plate Voltage: 125 V
• Grid-No. 2 Voltage: 125 V
• Grid-No. 1 Voltage: -20 V
• Amplification Factor: 4.7
• Grid-No. 1 Voltage for Plate Current of 1 mA: -75 V

Pentode Connection

When operated as a pentode (with Grid No. 3 connected to the cathode at the socket), two primary operating conditions are established:

Note: The plate and grid-No. 2 currents under Condition A are measured using a recurrent waveform method.

Horizontal-Deflection Amplifier Service

For horizontal-deflection amplifier service in 525-line, 30-frame television systems, the 17JR6 is rated under the Design-Maximum system as follows:

Maximum Ratings

• Plate Supply Voltage: 770 V
• Peak Positive-Pulse Plate Voltage: 6500 V (with a pulse duration not exceeding 15% of one horizontal scanning cycle, or 10 µs)
• Peak Negative-Pulse Plate Voltage: 1500 V
• Grid-No. 3 Voltage: 75 V (a positive bias up to 30 V typical may be applied to minimize "snivets" interference)
• Grid-No. 2 Voltage: 220 V
• Grid-No. 1 Voltage (Negative-bias value): 55 V
• Peak Negative-Pulse Grid-No. 1 Voltage: 330 V
• Peak Cathode Current: 950 mA
• Average Cathode Current: 275 mA
• Grid-No. 2 Input: 3.5 W
• Plate Dissipation: 17 W (a bias resistor or other protective means is required in the absence of excitation)
• Bulb Temperature (at hottest point): 240 °C

Maximum Circuit Values

• Grid-No. 1-Circuit Resistance:
  • Cathode bias (with minimum cathode resistance of 100 Ω): 1 megohm
  • Grid-leak bias (with signal peak clamped to zero bias): 10 megohms
  • Fixed bias (where positive grid current is not drawn): 0.47 megohm
  • Grid-resistor-bias: 0.47 megohm
  • Plate-pulsed operation: 10 megohms

Vertical-Deflection Amplifier Service

When utilized in vertical-deflection amplifier service for 525-line, 30-frame television systems, the 17JR6 is subject to the following Design-Maximum ratings:

Maximum Ratings

• DC Plate Voltage: 425 V
• Peak Positive-Pulse Plate Voltage (Absolute-Maximum Value): 2000 V (with a pulse duration not exceeding 15% of the vertical scanning cycle, or 2.5 ms)
• DC Grid-No. 3 and Diode-Plate Voltage: -150 V
• DC Grid-No. 2 Voltage: 330 V
• Peak Negative-Pulse Grid-No. 1 Voltage: 150 V
• Average Cathode Current: 70 mA
• Peak Cathode Current: 250 mA
• Average Diode-Plate (and Grid-No. 3) Current: 1 mA
• Plate Dissipation: 10 W
• Grid-No. 2 Input: 2 W
• Bulb Temperature (at hottest point): 240 °C

Maximum Circuit Values

• Grid-No. 1-Circuit Resistance:
  • For grid-No. 1-resistor-bias or cathode-bias: 2.2 megohms

Qualitative Curve Analysis

The electrical behavior of the 17JR6 is characterized by distinct plate and grid-No. 2 relationships:

• Plate and Grid-No. 2 Characteristics at Grid-No. 2 Voltage of 125 V: The plate current ($I_b$) curves exhibit a sharp knee behavior below a plate voltage of 50 V. At a grid-No. 1 voltage ($E_{[c1](/tubes/C1)}$) of 0 V, the plate current rises steeply, reaching peak values between 300 mA and nearly 500 mA at plate voltages near 100 V. Conversely, the grid-No. 2 current ($I_{c2}$) is at its maximum at low plate voltages (reaching approximately 100 mA at zero plate voltage) and drops rapidly as the plate voltage exceeds 50 V.
• Plate Characteristics at Grid-No. 1 Voltage of 0 V across varying Grid-No. 2 Voltages: When evaluated with Grid No. 3 connected to the cathode and Grid No. 1 at 0 V, the plate current curves for various grid-No. 2 voltages (ranging from 50 V to 175 V) demonstrate that the knee voltage increases with higher grid-No. 2 potentials. Saturation levels are highly dependent on the grid-No. 2 voltage, with peak plate currents exceeding 800 mA to 900 mA when the grid-No. 2 voltage is set to 175 V and the plate voltage reaches 400 V.

Technical Summary

The 17JR6 is a high-performance Novar beam power tube designed for demanding television deflection applications. Featuring a 16.8 V, 0.6 A heater with a controlled 11-second warm-up time, it is optimized for series-string or parallel heater circuits. The tube is capable of handling high peak positive-pulse plate voltages up to 6500 V in horizontal-deflection service and 2000 V in vertical-deflection service. With its high peak cathode current capability (up to 950 mA in horizontal service) and robust plate dissipation ratings (up to 17 W), the 17JR6 provides reliable performance in low B+ black-and-white television receivers.