MIL-DTL-13253E
4.6.1.4.4 Noncompliance. If a sample fails to pass group C inspection, the supplier shall take
corrective action on the materials or processes, or both, as warranted, and on all units of product, which
can be corrected and which were manufactured under essentially the same conditions, with essentially
the same materials, processes, etc., and which are considered subject to the same failure. Acceptance
of the product shall be discontinued until corrective action, acceptable to the Government, has been
taken. After the corrective action has been taken, group C inspection shall be repeated on additional
sample units (all inspection, or the inspection which the original sample failed, at the option of the
Government). Groups A and B inspections may be reinstituted. However, final acceptance shall be
withheld until the group C re-inspection has shown that the corrective action was successful. In the event
of failure after re-inspection, information concerning the failure and corrective action taken shall be
furnished to the responsible inspection activity and the procuring activity.
4.7 Methods of examination and test.
4.7.1 Visual and mechanical examination. Handsets shall be examined to verify that the materials,
design, construction, physical dimensions, marking, and workmanship are in accordance with the
4.7.2 Dielectric withstanding voltage (see 3.5). The handset shall be tested with the microphone
element and the earphone element removed. The handset shall be tested In accordance with method
301 of MIL-STD-202. The following details shall apply:
a. Test voltage
-
440 volts.
b. Nature of potential -
60 Hz ac.
c. Points of application -
The test voltage shall be applied between the wiring and adjacent metal
nonconductors and ground of the wired handset handle.
4.7.3 Impedance (earphone) (see 3.6). The magnetic earphone elements shall be measured, while
located on a 6 cm3 coupler, as specified for the response test in MIL-M-13189. Connect the magnetic
earphone element, in series with a non-inductive resistance at least 100 times the rated impedance of the
magnetic earphone element, to a source of alternating voltage at 1,000 Hz. Adjust the source voltage to
obtain an rms voltage across the magnetic earphone element, as specified in table VII as follows:
TABLE VII. Earphone Impedance test values.
RMS voltage
Rated impedance of
across magnetic
magnetic
earphone elements
earphone elements
ohms
volt
128
0.057
256
0.080
3,000
0.275
Replace the magnetic earphone element with a variable non-inductive resistance, and without changing
the source voltage, adjust the variable resistance to obtain the same voltage as for the magnetic
earphone element. The ohmic value of the resistance necessary to obtain the rms voltage reading shall
be considered as the impedance of the magnetic earphone element.
4.7.4 Resistance (microphone, see 3.7). The resistance for the test shall be taken as the maximum
resistance, (determined from the potential (voltage) dc and current dc readings), occurring during the
periods from 5 seconds after the agitation is completed until the end of the test.
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