MIL-PRF-19978K
4.7.20.3 Extended life (see 3.24). Sample units that have been subjected to 2,000 hours of life test as specified
in 4.7.20.1 and 4.7.20.2, shall remain on test for an additional 4,000 hours +72 hours. -0 hours. After completion of
the 6,000-hour life test time capacitors shall be measured as specified in 4.7.20.1e.
4.7.21 Fungus (see 3.25). Capacitors shall be tested in accordance with method 508 of MIL-STD-810. Pretest
and post-test measurements are not required.
4.7.22 Resistance to solvents (see 3.26) Capacitors shall be tested in accordance with method 215 of MIL-STD-
202. The following details shall apply:
a. Portion of specimen to be brushed: That portion on which marking is present.
b. Number of specimens to be tested: As specified in applicable inspection tables.
c. Permissible extent of damage: As specified in 3.26.
4.7.23 Resistance to soldering heat (see 3.27) (applicable to wire-lead capacitors only). Capacitors shall be
tested in accordance with method 210 of MIL-STD-202. The following details shall apply:
a. Test condition letter: C
b. Cooling time prior to measurement after test: 10 minutes 1 minute.
c. Measurements after test: Insulation resistance, capacitance, and dissipation factor shall be measured at
+25°C 3°C as specified in 4.7.8, 4.7.9, and 4.7.10, respectively.
4.7.24 Moisture resistance (see 3.28). Capacitors and retainers shall be tested in accordance with method 107 of
MIL-STD-202, test condition A, except that no measurement shall be made before and after cycling. Capacitors
shall then be tested in accordance with method 106 of MIL-STD-202. The following details and exceptions shall
apply:
a. Initial measurements: Not applicable.
b. Polarization voltage: During steps 1 through 6, inclusive, a dc potential of 100 volts shall be applied across
the terminals of 50 percent of the capacitors. No potential shall be applied to the remaining 50 percent of
the capacitors.
c. Loading voltage: Not applicable.
d. Final measurements: After the final cycle, the capacitors shall be conditioned at +25C 5C and a relative
humidity of 50 percent 5 percent for a period of at least 22 hours but not more. Dielectric withstanding
voltage and insulation resistance at +25C shall be measured on insulating sleeves as specified in 4.7.6
and 4.7.8, respectively. The test potential shall be applied between the case and a piece of metal foil
placed around the insulating sleeve. The metal foil shall be of such dimension as to allow at least .125 inch
(3.18 mm) surface exposure of the insulating sleeve on each end. In addition, dielectric withstanding
voltage, insulation resistance, capacitance, and dissipation factor at +25C, of all capacitors shall be
After the test, capacitors and retainers shall be visually examined for evidence of harmful corrosion and obliteration
of marking; capacitors shall be examined for unwrapping of or mechanical damage to insulated sleeves, when
applicable.
4.7.25 Flashpoint of impregnant or filling compound (see 3.29). The flashpoint of impregnant or filling compound
shall be measured as specified in ASTM D92, except that the fire point and precision do not apply. "Impregnant or
filling compound" shall be substituted for the word "oil" throughout the test method.
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