Downloaded from https://www.everyspec.com MIL-STD-1311D 4.2 Methods of reference. Applicable test methods contained herein shall be referenced on the TSS by specifying the method number of this standard and details required by the test method. Applicable methods shall be referenced without specifying a revision letter. Paragraph numbers within test methods shall not be referenced. If a particular paragraph(s) is applicable, the title shall be specified. 4.3 Order of precedence.
Unless otherwise specified, in the event of conflict between this standard and the tube specification sheet (TSS), the latter shall govern (see MIL-PRF-1, paragraphs 2.4, 3.1.1 and A.2.4, Order of precedence.) 4.3.1 Quantity measurement. When it is stated in any test method that a quantity is to be measured, it is implied that the measurement, after application of any necessary correction factors or calculations, is to be within the limits specified on the TSS, or herein. Consequently, the words ". . . and shall be within the limits specified . . ." are frequently implied but not stated, to avoid constant repetition. 4.3.2 Parameter values.
Where any specific value or limit for a parameter is stated herein, the TSS may specify a different value, for good reasons; such value will automatically govern, in accordance with MIL-PRF-1 order of precedence provisions. Consequently the words ". . . or the specified value . . ." are frequently implied but not stated, to avoid constant repetition. In the interests of standardization, TSS's should not adopt different values of such parameters without good reason. 4.4 Obsolescent test methods. Test methods labeled "OBSOLESCENT" are retained in this standard because they are specified on TSS's for a limited number of older tubes. Obsolescent methods shall not be specified on new TSS.
If a similar measurement is required for new tube types, a new test method will be prepared under a different number, reflecting current practice. Obsolescent methods will be deleted from this standard when no further requirements exist. 4.5 Destructive tests. Tubes subjected to a destructive test (see MIL-PRF-1, para. 4.1) shall not be delivered on the contract or order. The manufacturer has the option of using different or the same sample tubes when more than one destructive test is required.
Tubes subjected to deteriorating tests, such as environmental, physical, or life tests, which have electrical tests specified as end-point limits, shall conform to the initial limits for those electrical tests, prior to being subjected to deteriorating tests. 4.6 Alternate test methods. An alternate test method may be substituted for a method specified herein provided it is demonstrated to the qualifying Government activity that there is adequate correlation between the results of the manufacturer's test method and the test method specified herein, and provided that such substitution in no manner relaxes the requirements of MIL- PRF-1 and of this standard.
The schematic diagrams and description of the test equipment to be used, shall be made available for review by the qualifying activity (DLA Land and Maritime-VQE, P.O. Box 3990, Columbus, OH 43218). 4.7 Additional testing. The manufacturer may make such additional tests as he may deem necessary to insure proper control of his product. 4.8 General test conditions. 4.8.1 Order of testing. Conformance inspection tests may be conducted in any order, at the discretion of the manufacturer. For qualification testing (verification), the following tests, when specified, shall be performed after all other tests in any sequence:
bump, emission, pulse cathode current, rough handling (formerly drop test), shock, and vibration. 4.8.2 Ambient conditions. Unless otherwise specified, test temperature, relative humidity, and atmospheric pressure conditions shall be in accordance with GENERAL REQUIREMENTS of MIL-STD-202. 4.8.3 Calibration of measuring and test equipment. Calibration and certification procedures for standards and instruments used to test and measure completely assembled electron tubes acquired in accordance with MIL-PRF-1, shall be as specified in NCSL- Z540.3. In addition, the following requirements shall apply: a.
The accuracy of a calibrating instrument shall be at least four times greater than that of the item being calibrated. b. Calibration intervals shall be established on the basis of stability, purpose, and degree of usage for the standards and instruments and shall not exceed a 1-year interval except as indicated below. Intervals shall be shortened as required to assure continued accuracy, as evidenced by the results of preceding calibrations, and may be lengthened only when the results of previous calibrations provide definite indications that such action will not adversely effect the accuracy of the system.
The individual changes shall be approved by the qualifying activity (DLA Land and Maritime-VQE, P.O. Box 3990, Columbus, OH 43218). 4.8.4 Accuracy of measurements. The specified limits are for values obtained with the specified test conditions and measuring equipment of accuracy consistent with general industry practice and calibrated in accordance with NCSL-Z540.3. Allowances are made for normal distribution and measuring instrument accuracy in establishing test specification sheet test conditions and test limits.
Accuracy of measurements shall be appropriate to the test parameter(s) being measured and specific point instrument calibrations may be utilized when better accuracy than that specified and maintained for the basic measuring instrument is desired. 3