MIL-DTL-38449D
b. During the vibration, the unit shall be load cycled using a 3-ampere load and
sequencing described in the life test (4.4.8) except at -54°C in the fourth part the unit shall be in
a non-operating condition.
c. During vibration; the normally closed relay contacts shall be monitored for momentary
opening. An opening time of 0.5 millisecond or greater shall constitute failure of the unit. The
device used to detect opening of a closed contact for more than the specified time shall lock in an
alarm condition. When a fault occurs, the alarm shall sound and shall not cease if the fault
ceases. Manual reset shall be the only way to clear the alarm.
d. The test unit shall be functionally tested (4.4.3) at intervals of 500 load cycles. The
number of load cycles shall be recorded and may apply toward the life test completion.
e. During the fourth part at -54°C, the vibration levels shall be as follows:
10-50 Hz
±0.050 inch DA (double-amplitude)
50-80 Hz
±6g
80-105 Hz
±0.018 inch DA
105-190 Hz
±10g
190-270 Hz
±0.0054 inch DA
270-2,000 Hz
±20g
4.4.8 Life. The unit shall be load cycled at room temperature connected in the test circuit of
Figure 6 or a circuit approved by the qualifying activity. The unit shall be functionally tested as
specified in 4.4.3 at intervals of 5,000 load cycles. The number of load cycles accumulated
during vibration testing maybe added to the number of cycles required during life test, to total
50,000 cycles. One cycle shall consist of:
a. READY for 1 ±0.1 second. 28V dc shall be applied to pin A/1 and returned to
pin B/2.
b. CONTACT for 1 ±0.1 second. Unit shall be placed in CONTACT by applying a 28V
dc to 30V dc, 3- to 15-millisecond pulse to pin F/6.
c. DISCONNECT for 1 ±0.1 second. The unit shall be placed in DISCONNECT by
applying a second 28V dc to 30V dc, 3- to 15-millisecond pulse to pin F/6.
d. OFF for 1 ±0.1 second. Power shall be removed from pin A/1.
e. In addition for classes 3 and 4 amplifiers only, an oscillator (set to -1 dBm, 1 kHz)
shall be connected to pins 9 and 12; output pins 6 and 2 shall be terminated with 2.4K-ohm load.
4.4.9 Radio frequency interference. The amplifier shall be subjected to the following tests in
accordance with MIL-STD-461. Noise resulting from actuation of the relay contacts shall be
excluded from the measurements.
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