MIL-PRF-27208F
4.7.22 Immersion (not applicable to L terminations) (see 3.27). The surface shall be clean of any foreign matter
immediately before immersion.
Precaution: Precondition resistors in an oven at 125oC ±5oC for 13 minutes ±2 minutes, or use a
a.
o
o
fluorocarbon bath maintained at 125 C ±5 C for a period to 1.5 minutes ±0.5 minutes. Upon completion of
precondition, allow resistors to stabilize to room temperature for approximately 13 minutes ±2 minutes.
o
o
o
Immersion: Immerse resistors (not to exceed 30 samples) into a fluorocarbon bath held at 85 C, +5 C, -0 C
b.
for a period of 60 seconds ±5 seconds. The resistor shall be completely submerged in the bath, with no part
at a depth of less than 1 inch. Resistors shall be shaken for a maximum of 5 seconds and shall remain in
the bath for a period of 1 minute ±5 seconds. Visually examine resistors for inadequate seals, as evidenced
by a continuous stream of bubbles emanating from any concentrated point on the resistor.
c.
Dye penetrate verification: A five piece sample of the product exhibiting inconclusive evidence of
o
compliance to immersion requirements (see 3.27), shall be preconditioned in an oven, stabilized at 125 C
o
o
o
±5 C for 13 minutes ±2minutes, or preconditioned in a fluorocarbon bath maintained at 125 C ±5 C for 1
minute ±5 seconds and immediately upon removal (within 5 seconds), shall be submerged in a dye
penetrate solution for 30 seconds minimum. The dye penetrate solution shall consist of 0.1 gram per liter or
equivalent, of a soluble stain dye such as crystal violet dissolved in deionized water maintained at room
ambient temperature. Upon removal from the dye solution, the sample shall be held at room temperature
until external surfaces are dry. The sample shall then be carefully opened and examined under 10X to 30X
magnification for evidence of dye penetration into the sealed cavity. Evidence of such penetration verifies
loss of immersion seal, and lack of such evidence verifies compliance to the requirement.
4.7.23 Fungus (see 3.28). Resistors shall be tested in accordance with method 508 of MIL-STD-810. Resistors
shall be examined for evidence of mechanical damage.
5. PACKAGING
5.1 Packaging. For acquisition purposes, the packaging requirements shall be as specified in the contract or order
(see 6.2). When packaging of materiel is to be performed by DoD or in-house contractor personnel, these personnel
need to contact the responsible packaging activity to ascertain packaging requirements. Packaging requirements are
maintained by the Inventory Control Point's packaging activities within the Military Service or Defense Agency, or
within the military service's system commands. Packaging data retrieval is available from the managing Military
Department's or Defense Agency's automated packaging files, CD-ROM products, or by contacting the responsible
packaging activity.
6. NOTES
(This section contains information of a general or explanatory nature that may be helpful, but is not mandatory).
6.1 Intended use. The resistors covered by this specification are military unique due to the fact that these devices
must be able to operate satisfactorily in military systems under the following demanding conditions: 15 g's of high
frequency vibration, 50 g's of shock (specified pulse), 50 g's of acceleration and resistant to salt corrosion. In
addition, these military requirements are verified under a qualification system. Commercial components are not
designed to withstand these military environmental conditions.
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