MIL-STD-1311B Method 1501A Electron Tube Test Method Manual PDF (EN)

Downloaded from https://www.everyspec.com t4;4i~;O;1311B 4 March 19B3 (. MILITARY STANDARD TEsT ME THOOS FOR ELECTRON TUBES TO ALL HOLOERS OF MI L- STO-1311B 1. THE FOLLOWING TEST METHOO HAS BEEN REV ISEO ANO SUPERSEDES THE TEST METHOO LISTEO: REV ISEO METHOD OATE SUPERSEOEO’ METHOO 1501A 4 tfarch 1983 1501 OATE 2. RETAIN THIS NOTICE PAGE AND INSERT BEFORE THE TABLE OF CONTENTS. 19 April 1968 3. Holders of MI L- STO-1311B will verffy that changes and additions indicated above have been entered. The notice page will be retained as a check sheet. This issuance, together with appended pages, is a separate publication.

Each notice is to be retained by stocking points until the Military Standard is completely revised or canceled. Custodians: Army - ER Navy - EC Air Force - 85 Preparing activity: Navy - EC (Project 5960-3311) Review activities: Army - Ml, AR Air FOPce - 11, IT, 99 oLA - ES User activities: ArrAy - AV, ME, SM Navy - AS, OS, MC, CG Air Force - 19 Agent: oLA - ES FSC 5960

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I MiL-STD-1311B 28 March 1975 Downloaded from https://www.everyspec.com .... :- . -. 3 .L, METHOD 1501A - Continued life test sample shall be used. Any tube found inoperable not be considered in the calculation of this average. during life testing shall 2.5 A resubmitted lot shall be subjected to all quality part 1 and 2 tests, except the following: conformance inspection, Vibration tests Shock tests Physical (including dimensions Secureness of base, cap, or insert Lead fatigue BarOWtric pressure, reduced Base strain [miniature).

Glass strain 2.6 Not more than one accidental breakage shall be allowed in the life-test In the event that one life-test tube is accidental $?m?~~”life-test sample shall be, based upon the remaining t.~e!r;[e~~ea~;;F~;!ility provided the broken tube was not known to be a defective. /.. .,] supersedes METHOO 1501. of 19 April’ 1968. METHOO 1501A 1501-2 G a-.MuI7 -!.7r..O..,C. ,—.W.,2OI4 *.,

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., Downloaded from https://www.everyspec.com MI L- STD-1311B 2B March 1975 METHOO 1501A INTERMITTENT LIFE 1. When intermittent life-test is performed, the tubes shall be operated under the specified test conditions with the filament or heater supply interrupted periodically. There shall be 12 to 25 uniform cycles, total ling approximately 20 hours of operation each 24 hours. The filament or heater supply shall be applied and removed instantaneously. Other potentials may be applied continuously, at the option of the manufacturer. The accumulation of the time shall be the time considered in determining compliance with the minimum specified time value.

The filament or heater-supply impedance shall not exceed 10 percent of the hot filament-load impedance. Warmup time, tk, when specified on the TSS as a test condition for intermittent life teSt, shall be adhered to at the beginning of each period. This is a destructive test. 2. Tube intermittent life-test procedure. Regular life test shall be in effect initially and shall continue In ettect untl I the eligibility criteria for the reduced-hours life test have been met. Sampling shall be as specified in. MI L-E-l. This is a destructive test. 2.1 Regular life test. [a) Regular life test shall be conducted for 500 hours.

(b) Regular life-test acceptance shall be on the basis of the specified 200- and 500-hour life,-test end-point limits. 2.2 Reduced-hours life test. [a) Eligibility for reduced-hours life tests is established when no first sample failure due to the regular 500-hour life test has occurred in the preceding 3 consecutive lots. (b) Reduced hours’ life test shall be conducted for 200 hours and acceptance shall be based on the 500-hour life-test end-point limits. Two 200-hour life-test. lot failures occurr{ng the last 3 consecutive lots shall result in loss of eligibility for reduced-hours life testing.

(c) The life-test sample from the first lot accepted each quarter shall continue on life test for an additional 300 hours (5OO hours total life-test time). Failure of this sample to meet the 500-hour life-test end- DOint limits shall result in loss of eligibility for reduced-hours test; ng. I 2.3 The life-te sample shii’ be read at the following times: O hours 200 +24 -0 hours ~oo +24 -0 hours Additional reading periods may be used at the discretion of the tube manufacturer. 2.4 Acceptance criteria.

The lot shall be considered satisfactory for acceptance If the specified allowabl e defects are not exceeded and the change in average of any characteristic in the life-test sample specified for life-test control of averages is not exceeded. The average percentage change shall be obtained from the determination of the individual changes for each tube In the life test sample from the zero-hour value for the specified characteristics. For purposes of computation of this average percentage change, the absolute values of the individual changes for each tube in the Supersedes METHoO 1501 of 19 April 1968. 1501-1 METHOO 1501A

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