MIL-DTL-917F(SH)
3.20 Information assurance (IA). Electrical equipment that contains interfaces for external digital
communications, whether used or unused, shall implement an IA plan approved by NAVSEA. Refer to NIST
Special Publication (SP) 800-82 for guidance. See 6.2 for other IA requirements.
4. VERIFICATION
4.1 General. Examination and tests shall be as specified herein and in the individual equipment specification.
Sampling for examination and tests shall be as specified in the individual equipment specification (see 6.2).
4.2 Classification of inspections. The inspection requirements specified herein are classified as follows:
a.
Manufacturing screening tests (see 4.3).
b.
Conformance inspection (see 4.4).
4.3 Manufacturing screening tests. Manufacturing screening tests are exclusively required for electronic
systems and only those portions of electric power equipment that are predominantly electronic, such as printed
wiring assemblies and subassemblies containing semiconductors. These tests shall include the temperature cycling
and random vibration tests of MIL-HDBK-344 using the process guidance found in MIL-HDBK-2164. The
purpose of the tests is to stimulate the early occurrence of failures due to manufacturing defects in both parts and
workmanship. A 100-hour burn-in test (see 4.3.3) may be performed in lieu of environmental stress screening.
4.3.1 Level of testing. Screening tests shall be performed on equipment having both first article requirements
and qualification requirements as specified in the individual equipment specification (see 6.2).
4.3.2 Environmental stress screening test procedures and sequence. Test procedures shall show the chosen
system or subsystem. Tests of complete equipment that are referred to as "solid state" shall be tested in entirety,
unless capabilities of available test equipment cause limitations of equipment size that can be tested. Testing should
follow the process guidance provided for the environmental test screening constituents as defined in
MIL-HDBK-2164. The test sequence shall be random vibration, thermal cycling, and random vibration. Thermal
cycling shall be a minimum of 10 cycles for all equipment for temperature ranges defined in the applicable
equipment specification. If vibration tests require subcontracting effort, these tests may be accomplished
independent of thermal cycling and the test sequence as defined by MIL-HDBK-2164. Test results shall show
defect-free operation after the random vibration test of circuit cards and assemblies.
4.3.2.1 Circuit card vibration testing. All circuit cards shall be given a random vibration test hard mounted to
the test table according to the random vibration spectrum of figure 1. A supplementary test system must be
provided to verify card failures of electrical nature to be used before and after the test. Multiple cards may be tested
at one time, in the unenergized card mode, at standard ambient test temperature. The preferred axis of vibration for
circuit cards will be in a direction perpendicular to the plane of the card. Dual axis testing (at a 45-degree angle) is
acceptable provided that levels of the random vibration spectrum of figure 1 are achieved in the direction
perpendicular to the plane of the card. The test sequence shall be a run of 5 minutes of pre-defect-free operation,
followed by 5 minutes of defect-free vibration. Failures must be treated using the guidance found in
MIL-HDBK-2164, and be defined according to the pre-test supplementary test system results. Circuit card testing
shall be preliminary to complete assembly and subassembly testing.
4.3.2.2 Vibration and thermal cycling of assemblies and subassemblies. The preferred method is to evaluate
the total system rather than system parts using the guidance for the environmental stress screening test constituent's
test sequence in MIL-HDBK-2164. The test sequence shall include preliminary vibration tests, preliminary thermal
cycling, failure-free thermal cycling, and final failure-free vibration testing. Testing of subsystems is acceptable if
equipment to evaluate a total system is not available or the total system includes other electrical components which
do not require environmental stress screening such as generators, motors, and so forth.
4.3.2.3 Vibration axis. Where electronic components of assemblies and subassemblies are oriented in more
than one plane, such equipment should be shaken sequentially in predetermined selected axis considered essential
and presented in the test plan. Where vibration in more than one axis is required, the duration of random vibration
should be at least 5 minutes for each axis during the periods indicated in MIL-HDBK-2164.
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