MIL-PRF-39015 Resistors, Variable, Wirewound, \(Lead Screw Actuated\), Nonestablished Reliability, And Established Reliability, General Specification ForThis specification covers the general requirements for nonestablished reliability \(non-ER\) and established reliability \(ER\), lead screw actuated; wirewound variable resistors with a contact bearing uniformly over the surface of the entire resistive element, wound linearly, when positioned by a multiturn lead screw actuator. These resistors are capable of full load operation \(when the maximum resistance is engaged\), at a maximum temperature of 85OC and are capable for continuous operation, when properly derated, at maximum temperature of 150OC \(see 3.6\), with a resistance tolerance of ??5 percent. The ER resistors have life failure rate \(FR\) levels ranging from 1.0 percent to 0.001 percent per 1,000 hours \(see 1.2.1.4\). These FR levels are established at a 60 percent confidence level on the basis of life tests.

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MIL-PRF-39015E

3.32 Resistance to solvents. When resistors are tested as specified in 4.8.26, there shall be no

evidence of mechanical damage and the markings shall remain legible.

3.33 Fungus. All external materials shall be nonnutrient to fungus growth or shall be treated to retard

fungus growth. The manufacturer shall verify by certification that all external materials are fungus

resistant or shall test the resistors as specified in 4.8.27. There shall be no evidence of fungus growth on

the external surfaces.

3.34 Marking. Resistors shall be marked with the PIN (see 1.2.1 and 3.1) and "JAN" brand. In

addition, the resistor shall be date and source coded in accordance with MIL-STD-1285. Where the date

coding does not provide specific lot identification, the manufacturer shall mark the resistor with a lot code

symbol. Where required, the PIN may appear on two lines as shown in the following example:

M39015/2

Document number and slash sheet.

-001PM

Resistance dash number, pin style, product level.

Marking shall remain legible at the end of all tests. The date lot code and lot symbol shall provide

traceability through all production operation and shall represent a specific critical point consistently

provide by the manufacturer.

3.34.1 JAN and J marking. The United States Government has adopted, and is exercising legitimate

control over the certification marks "JAN" and "J", respectively, to indicate so marked or identified are

manufactured to, and meet all the requirements of specifications. Accordingly, items acquired to, and

meeting all of the criteria specified herein and in applicable specifications shall bear the certification mark

"JAN" except that items too small to bear the certification mark "JAN" shall bear the letter "J". The "JAN"

or "J" shall be placed immediately before the part number except that if such location would place a

hardship on the manufacturer in connection with such marking, the "JAN" or "J" may be located on the

first line above or below the part number. Items furnished under contracts or orders which either permit

or require deviation from the conditions or requirements specified herein or in applicable specifications

shall not bear "JAN" or "J". In the event item fails to meet the requirements of this specification and the

applicable specification sheets or associated specifications, the manufacturer shall remove completely

the military part number and the "JAN" or the "J" from the sample tested and also from all items

represented by the sample. The "JAN" or "J" certification mark shall not be used on products acquired to

contractor drawings or specifications. The United States Government has obtained Certificate of

Registration Number 504,860 for the certification mark "JAN", and Registration Number 1,586,261 for the

certification mark "J".

3.34.2 Supplying to higher product levels. A manufacturer may supply to all higher FR levels than that

to which they are qualified. Parts qualified and marked to lower FR levels, with procuring agency

approval, are substitutable for higher rate level parts, and shall not be remarked unless specified in the

contract or purchase order (see 6.2 and table IV).

TABLE IV. Product level substitution.

Product

Acceptable product

level

level substitution

S (.001)

R (.01)

S, R

P (0.1)

S, R, P

M (1.0)

S, R, P, M

C (non-ER)