MIL-DTL-62738A(AT)
4.2.6.5 Burn-in. When required (see 6.2), the burn-in shall consist of three temperature
cycles and a six gravity unit (g) root mean square (rms) random vibration as follows:
a. Temperature cycle. Each temperature cycle shall consist of 30 minutes at -60°F
(-51°C) and 30 minutes at +125°F (52°C). The rate of temperature change
between temperature extremes shall be not less than 5°F (2.8°C) per minute.
Power shall be applied to the PWA for not less than 30 minutes from 20°F (-7°C)
through the completion of each high-temperature soak.
b. Random vibration. Following all temperature cycling, the PWA shall be hard
mounted to the vibration table so that the axis of vibration is perpendicular to the
plane of the PWA. The vibration shall be at room ambient temperature for a
period of 10 minutes as shown in figure 7.
NOTE: PWAs being procured for simultaneous installation in VTMs being procured do not have
to be subjected to "burn-in" provided the VTMs are subjected to a 16-hour "power on"
burn-in.
5. PACKAGING
5.1 Packaging. For acquisition purposes, the packaging requirements shall be as specified
in the contract or order (see 6.2). When actual packaging of materiel is to be performed by DoD
personnel, these personnel need to contact the responsible packaging activity to ascertain requisite
packaging requirements. Packaging requirements are maintained by the Inventory Control Point's
packaging activity within the Military Department or Defense Agency, or within the Military
Department's System Command. Packaging data retrieval is available from the managing Military
Department's or Defense Agency's automated packaging files, CD-ROM products, or by
contacting the responsible packaging activity.
6. NOTES
(This section contains information of a general or explanatory nature which may be
helpful, but is not mandatory.)
6.1 Intended use. The PWA consists of special circuitry to interface to an automotive
spark ignition system. This module has Points Voltage (POINTS V), and Ignition Kill
(IGN KILL) as its inputs, and Ignition Signal (ING SIG) and POINTS V as its outputs. This
module can either interrupt or continuously inhibit spark ignition according to the control signal
IGN KILL. The Points Signal is transformed by circuitry utilizing an optocoupler (UI) into logic
levels suitable for detection by the VTM through the signal IGN SIG. The interrupt or inhibit
signal, IGN KILL, is transformed from VTM logic levels into signals driving a transistor circuit
(Q1 and Q2). The transistor circuit pulls the POINTS V down to a level such that the spark plugs
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