MIL-PRF-39035 Resistor, Variable, Nonwirewound \(Adjustment Type\), Nonestablished Reliability, And Established Reliability, General Specification ForThis specification covers the general requirements for nonestablished reliability \(non-ER\) and established reliability \(ER\), multiturn lead-screw actuated, and single-turn, nonwirewound, variable resistors with a contact bearing uniformly over the surface of the entire resistive element, when positioned by an actuator. These resistors are capable of full-load operation \(when the maximum resistance is engaged\), at a maximum temperature of 150 Degrees C, with a resistance tolerance of ??10 percent. The ER resistors will have life failure rate levels ranging from 1.0 to 0.001 percent per 1,000 hours \(see 1.2.1.5\). These failure rate levels are established at a 60 percent confidence level maintained at 10 percent producer\'s risk on the basis of the life tests.

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MIL-PRF-39035E

DEPARTMENT OF DEFENSE STANDARDS

Tests Methods for Electronic and Electrical Components Parts.

Failure Rate Sampling Plans and Procedures.

Established Reliability and High Reliability Qualified Products List

(QPL) Systems for Electrical, Electronic, and Fiber Optic Parts

Specifications.

Marking of Electrical and Electronic Parts.

(Copies of these documents are available online at https://assist.daps.dla.mil/quicksearch/ or

https://assist.daps.dla.mil or from the Standardization Document Order Desk, 700 Robbins Avenue, Building 4D,

Philadelphia, PA 19111-5094).

2.3 Non-Government publications. The following documents form a part of this document to the extent specified

herein. Unless otherwise specified, the issues of the documents cited in the solicitation or contract (see 6.2).

ELECTRONIC INDUSTRIES ASSOCIATION (EIA)

Assessment of Average Outgoing Quality Levels in Parts Per Million

(PPM).

Statistical Process Control Systems (SPC).

(Applications for copies should be addressed to the Electronic Industries Association http//www.eia.org, 2500

Wilson Boulevard, Arlington, VA 22201-3834.)

2.4 Order of precedence. In the event of a conflict between the text of this document and the references cited

herein (except for related specification sheets), the text of this document takes precedence. Nothing in this

document, however, supersedes applicable laws and regulations unless a specific exemption has been obtained.

3. REQUIREMENTS

3.1 Specification sheets. The individual item requirements shall be as specified herein and in accordance with the

applicable specification sheet. In the event of any conflict between the requirements of this specification and the

specification sheet, the latter shall govern (see 6.2).

3.2 Qualification. Resistors furnished under this specification shall be products that are authorized by the

qualifying activity for listing on the applicable Qualified Products List (QPL) before contract award (see 4.4 and 6.3).

In addition, the manufacturer shall obtain certification from the qualifying activity that the QPL system requirements of

3.3 and 6.3 have been met and are being maintained. Authorized distributors that are approved to MIL-STD-790

distributors requirements by the QPL manufacturer are listed in the QPL.

3.3 QPL system. The manufacturer shall establish and maintain a QPL system for parts covered by this

specification. Requirements for this system are specified in MIL-STD-790 (all product levels) and MIL-STD-690 (ER

parts only). In addition, the manufacturer shall also establish A Statistical Process Control (SPC) and Part Per Million

(ppm) system that meets the requirements as described in 3.3.1 and 3.3.2 respectively.

3.3.1 SPC system. As part of the overall MIL-STD-790 QPL system, the manufacturer shall establish a SPC

system that meets the requirements of EIA-557. Typical manufacturing processes for application of SPC include,

printing of resistance elements, molding operation, lead attachment, and assembly. The reliability of resistors finished

under this specification shall be established and maintained in accordance with the requirements and procedures

specified in MIL-STD-790 and MIL-STD-690 with details and exceptions specified in 4.2, 4.4.4, and 4.7.