MIL-PRF-1/1717C
TABLE I. Testing and inspection - Continued.
14/ The tube shall be mounted in the socket in accordance with Drawing 276-JAN and vibrated with simple harmonic
motion. The peak acceleration over the frequency range shall be within ± 20 percent of the reference acceleration at
100 Hz. The frequency shall vary from 55 to 500 Hz and return to 55 Hz with approximate logarithmic progression
and shall require 4 minutes minimum, 6 minutes maximum, to traverse the range. Each tube shall be vibrated for 30
minutes in each axis X and Z except that if the cumulative result of test on 50 or more tubes of a construction show
that more than 75 percent of the tubes have a higher output voltage in one position, subsequent measurements need
to be taken only in the axis giving the higher readings. The voltages specified herein shall be applied to the tube
during vibration. The value of the alternating voltage, Ep, produced across the resistor, Rp, as a result of vibration,
shall be measured with a suitable device. The device shall have an appropriate voltage range, and shall have the
ability to measure, with an error less than 10 percent, the rms value of a sine wave of voltage at all frequencies from
20 to 20,000 Hz. The value of the vibrational output, Ep, shall not exceed the limit specified herein at any point in the
sweep frequency range during the last complete cycle of cycling vibration.
15/ The torque test shall be performed as follows:
a. The tube shall be held securely at the cathode connection. A force of 5 pounds shall be applied to the heater cup
without perceptible shock. This test may be made by applying the force at right angles to the inside of the cup at
a point 7/64-inch (2.77 mm) ± 1/64-inch (0.41 mm) from the cathode end of the tube. An approved equivalent
method may be used. The heater cup shall not loosen or short circuit to the cathode connection.
b. A rotational torque of 15 inch-pounds shall be applied between anode and cathode without shock.
c. A rotational torque of 40 inch-pounds shall be applied between anode and grid without shock.
d. A rotational torque of 30 inch-pounds shall be applied, both clockwise and counter-clockwise, between the anode
cooler and the anode contact surface, with no resulting loosening of the anode cooler or damage to the tube.
16/ At zero hours, measure the grid-anode capacitance (Cgp), and establish the drive conditions necessary to obtain 3.0
amperes peak anode current with an anode voltage of 1,000 V dc and a bias voltage of -40 V dc. The pulse width of
the modulator shall be 2 µs minimum and the duty cycle shall be 0.025 maximum.
At the completion of life test, Cgp is measured and the change from the original value (ĆCgp) may not exceed the
specified limit; under the same operating conditions and with the drive level determined at zero hours, check the
anode current at the end of life, and the change from the original value (Ćib) may not exceed the specified limit.
17/ All tests listed under conformance inspection, part 1, shall be performed at the conclusion of the holding period.
18/ In addition to the requirements specified herein, compatibility testing shall be required in the AN/ARN-52(V) Tacan
Set. A sample of 20 tubes shall be supplied to NAD Crane, Code QEEL on a noninterference basis. Of the 20 tubes
to be supplied, a sample of 4 tubes shall be selected for life tests. Each tube shall achieve a minimum of 500 hours
operation. In the event of no failures, the sample shall be considered as acceptable when a total of 1,600 hours have
been accumulated.
19/ This specification sheet uses accept on zero defect sampling plan, in accordance with MIL-PRF-1, table III.
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