MIL-K-70493 Keyboard, Data EntryThis specification establishes the requirements for manufacture and acceptance of the Data Entry Keyboard: 9355810, used in the Mortar Ballistics Computer MBC: M23. Throughout this specification this assembly is referenced as quot;keyboardquot;.

Pages 1 - 2 - 3 - 4 - 5 - 6 - 7 - 8 - 9 - 10 - 11 - 12 - 13

MIL-K-70493(AR)

3.2.3 Reliability.   When  specified  in  the  contract,  a  special sample  shall  be  subjected  to  reliability  testing.  The manufacturing and production techniques employed in the

fabrication of the keyboard shall not degrade the inherent reliability.        The inherent reliability shall not be less than

162,056 hours Mean Time Between Failures (MTBF).   (See 4 and 6)

3.3  Environmental.  The  keyboard  shall  meet  the  requirements specified herein unless otherwise specified.

3.3.1  Room  ambient  temperature.  The  requirements  of  this specification shall be met with the keyboard thermally stabilized at room ambient temperature of +160C  to +320C (+600F to

+900F), unless otherwise specified in the requirements paragraph.

3.3.2  Environmental  stress  screen  (ESS)  temperature.  The keyboard shall meet the requirements of 3.2.1.1 and 3.2.1.3 inclusive after having been exposed to a minimum of ten temperature cycles at temperatures of -57°C and +71°C (-71°F and +1600F).

3.3.3  Environmental  stress  screen  (ESS)  vibration.   The keyboard shall meet the requirements of 3.2.1.1 and 3.2.1.3 inclusive, after having been subjected to a random or pseudorandom vibration-which includes frequency content from 100 Hz to 1000 Hz

and up to a 3g RMS in two axis for a period of 10 minutes plus or

minus 15 seconds.

3.4  Fabrication.   The keyboard shall be manufactured in

accordance with drawing 9355810.

3.5 First article.   When specified in the contract, a sample shall be subjected to first article inspection (See 4 and 6).

3.6  W orkmanship.

The  workmanship  requirements  of  MIL-F-13926

and MIL-STD-454 shall be met. All components shall be fitted properly  and  firmly  in  their  respective  positions.  All  electrical connections shall be mechanically secure and electrically sound. There shall be no evidence of corrosion, burrs, roughness, sharp edges or other defects which could adversely affect its use or suitability for the purpose intended.

3.7 M aterials.

Materials shall be in accordance with

drawings,        material  specifications  and  general  specifications forming a part of this specification.

5