MIL-PRF-1/1633B
TABLE I. Testing and inspection - Continued.
13/ Test to be made in cavity in accordance with Drawing 160-JAN. The cavity shall be connected to a load with a VSW R less than
1.5/1. The oscillator output coupling and the grid or cathode resistor, or both, may be adjusted for maximum power output.
14/ The applied voltage pulse shall be measured with a noninductive resistor of 1,150 ohms ± 2 percent inserted in place of the tube.
The pulse shape shall be: tp = 3.0 µs ± 10 percent, tr = 0.4 µs maximum, and tf = 0.7 µs maximum. The pulse repetition rate shall
be adjusted so that Du = 0.0025 ± 5 percent with the above measured pulse length. Test in cavity in accordance with Drawing 279-
JAN. The cavity shall be connected to a load with a VSW R less than 1.5/1. The oscillator output coupling and the grid or cathode
resistor may be adjusted for maximum power output.
15/ Test to be conducted in power amplifier cavity as shown on Fidelitone Microwave Inc., Drawing JVM-D9819, or equivalent. Driving
power is defined as the net power delivered to the amplifier cavity input terminals and the reflected power shall be subtracted from
the incident power to obtain the net driving power. The output tuning shall be adjusted for maximum power output.
16/ This test shall be performed during the initial production and once each succeeding 12-calendar month period in which there is
production. An accept on zero defect sampling plan shall be used, with sample of three tubes having an acceptance number of zero
defects (see 26/). In the event of failure, the test shall be made as a part of conformance inspection, part 2, with an acceptance
level of 6.5 (see 26/). The regular "12 calendar month" sampling plan shall be reinstated after three consecutive samples have been
accepted.
17/ 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 axis,
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. This 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
vibration 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.
18/ The torque test shall be performed as follows:
a. The tube shall be held securely at the cathode connections. 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. This part of the test shall not be required if the space between the
heater cup and the cathode sleeve is completely filled with insulating material.
b. A torque of 15 inch-pounds shall be applied between anode and cathode without shock.
c. A torque of 40 inch-pounds shall be applied between anode and grid without shock.
d. A 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 cooler or damage to the tube.
19/ Test in jig made in accordance with Drawing 280-JAN. Each tube shall be subjected to a total of 15 shocks; that is, 5 shocks in
each axis X, Y, and Z, in any sequence. The applied shock wave shall be of approximate half-sine configuration, with duration
measured at the zero-axis level.
20/ The voltage E shall be 60 Hz ac applied between the anode and grid. No other voltages shall be applied. There shall be no
evidence of failure as indicated by arc-over.
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