TABLE I. Requirement or test - Continued.
1. See "reduced pressure (altitude) rating" and altitude, maximum peak voltage in MIL-PRF-1.
2. This test shall be performed at the conclusion of the holding period.
3. The insertion of a 1.0 MegΩ resistor in the grid circuit shall change the anode current by not more than 0.5 mA
dc. This is an alternative test.
4. Prior to this test, tubes shall be preheated a minimum of 5 minutes operating at the conditions specified below.
The 3-minute test shall not be permitted. Test at specified conditions within 3 seconds after preheating. Grid
emission shall be the last test performed on the sample selected for the grid-emission test.
5. A grid resistor of 0.1 MegΩ shall be added; however, this resistor shall not be used when a thyratron-type short
indicator is employed.
6. This test shall be conducted on the initial lot and thereafter on a lot approximately every 12 months. In the
event of lot failure, the lot shall be rejected and the succeeding lots shall be subjected to this test until a lot
passes. When one lot has passed, the 12-month rule shall apply.
7. Acceptance sampling procedure shall be in accordance with "Base-strain test, miniature sampling" (method
1121), except that data covered in "Acceptance and rejection criteria" shall be modified as follows:
(a) Accepted if no defectives for class "A", "B", or "C" defects, respectively (see method 1121), or if no
defectives are found in the sample.
(b) Rejected if there are any defectives for class "A", "B", or "C" defects, respectively.
8. Envelope temperature (TE) requirements, when measured in accordance with the temperature by conduction-
band measurement (MIL-STD-1311, method 1226), will be satisfied if a tube having bogey Ib (±5 percent) under
normal test conditions, is determined to operate at or above minimum specified temperature at any position in
the life-test rack.
9. The life-test sample shall consist of the lesser of 20 tubes or 10 percent of lot size and no tube failures shall be
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