MIL-PRF-914 Resistor Networks, Fixed, Film, Surface Mount, Nonestablished Reliability, And Established Reliability, General Specification ForThis specification covers the general requirements for nonestablished reliability \(non-ER\) and established reliability \(ER\), hermetically sealed \(see 3.27\) and nonhermetically sealed networks \(see 3.27.1\). These networks consist entirely of fixed, film resistors. They are primarily intended for use in surface mount applications where space is a major concern. ER resistors covered by this specification will have life failure rates \(FR\) ranging from 1 percent to 0.001 percent per 1,000 hours \(see 1.2.1.7\). The ER FR are established at a minimum 60-percent confidence level on the basis of life tests. Designers are CAUTIONED on using these resistors in pulse applications \(see 6.4.4\).

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MIL-PRF-914C

4.6.5.2 Subgroup 1. A sample of 13 parts shall be randomly selected. If one or more defects are found, the lot

shall be rescreened and defects removed. A new sample of 13 parts shall be randomly selected. If one or more

defects are found in this second sample, the inspection lot shall be rejected and shall not be supplied to this

specification.

4.6.5.3 Subgroup 2. A sample of 13 parts shall be randomly selected. If one or more defects are found, the lot

shall be rescreened and defects removed. A new sample of 13 parts shall be randomly selected. If one or more

defects are found in this second sample, the inspection lot shall be rejected and shall not be supplied to this

specification.

4.6.5.4 Subgroup 3. A sample of eight parts shall be randomly selected. If one or more defects are found, the lot

shall be rescreened and defects removed. A new sample of eight parts shall be randomly selected. If one or more

defects are found in this second sample, the inspection lot shall be rejected and shall not be supplied to this

specification.

4.6.5.5 Disposition of sample units. Sample units which have passed all the group B, subgroup 1 and subgroup 2

inspections, method A mounted networks only, may be delivered on the acquisition document provided they are

within resistance tolerance and meet requirements for visual and mechanical inspection. Sample units which have

been subjected to subgroup 3 inspections shall not be supplied to this specification.

TABLE XVI. Group B inspection (ER only).

Requirement

Test method

Sample

Number of

Inspection

paragraph

size

defects allowed

Subgroup 1 1/

Visual and mechanical examination

3.1 and 3.31

4.8.2

(when applicable)

Subgroup 2 2/

Resistance-temperature characteristic

Subgroup 3 2/

Resistance to solvents

Only applicable when marking inspection is not performed in group A inspection. No defects shall be

permitted. Marking shall remain legible at the end of all tests.

If the manufacturer can demonstrate that this test has been performed five consecutive times with zero

failures, the frequency of this test, with the approval of the qualifying activity, can be performed on an annual

basis. If the design, material, construction, or processing of the part is changed, or if there are any quality

problems or failures, the qualifying activity may require resumption of the original test frequency.

4.7 Periodic group C inspection (ER only). Periodic inspection shall consist of group C inspection tests specified in

table XVII, in the order shown. They shall be performed on sample units selected from lots that have passed group A

and group B inspection. Except where the results of these inspections show noncompliance with the applicable

requirements (see 4.7.6), delivery of products which have passed group A and group B inspections shall not be

delayed pending the results of these periodic inspections.