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|  MIL-P-48602(MU)
used in the design of test equipment shall be so selected and controlled
as to insure that the test equipment will reliably indicate acceptability
o f a product which does not exceed 90% of the prescribed tolerance limit,
and permit positive rejection when non-conforming. Construction shall be
such as to facilitate routine calibration of test equipment,
4.5.2.3 Inspection equipment design requirements for temperature test-
ing.- The volume of the test chamber shall conform to the test facilities
requirements of MIL-F-13926. The air temperatureat the control sensor
s h a l l be in accordance with the specified requirements within plus or minus
2.5F. The temperature gradient across the cross-sectional area occupied
by the test items shall not exceed 0.5F per foot in any direction. The
heat source of the test chamber shall be so located that radient heat, if
used, will not fall directly on the test item. Thermocouples or equivalent
temperature sensors utilized to determine or control the specified chamber
temperature shall be centrally located within the test chamber in the supply
a i r s t e a m , o r in the r e t u r n a i r s t r e a m , w h i c h e v e r p r o v i d e s t h e s p e c i f i e d t e s t
condition at the item under test and shall be baffled or otherwise protected
against radiation effects.
4.6 Test methods and procedures.
4.6.1 Storage temperature.- Testing equipment utilized in this test
shall conform to the requirements of 4.5.2.3. The Plotting board shall be
p l a c e d in the test chamber and the temperature of the chamber reduced, over
a period of 4 hours plus or minus 15 minutes, from room ambient temperature
to -50F. The plotting board shall be maintained at this temperature ex-
t r e m e for a minimum of 2 hours. Upon completion of the 2 hour exposurre the
temperature of the chamber shall be raised, over a period of 8 hours plus
or minus 15 minutes, to +140F. The plotting board shall remain at this
t e m p e r a t u r e for a minimum of 2 hours. Upon completion of the 2 hours ex-
p o s u r e the temperature of the chamber shall be reduced, over a period of
4 hours plus or minus 15 minutes, to room ambient temperature. The plotting
b o a r d shall then be removed from the test chamber and subjected to a visible
a n d tactile examination. The plotting board shall show no evidence of phys-
ical failure, or damage. The plotting board shall then be subjected to the
test in 4.6.2 to determine overall compliance with the requirements of 3.3.1.
4.6.2 Operating temperature.- Testing equipment utilized in this test
shall conform to the requirements of 4.5.2.3. The plotting board shall be
p l a c e d in the test chamber and the temperature of the chamber reduced, over
a period of 4 hours plus or minus 15 minutes, from room temperature to -40"F.
The plotting board shall be maintained at this extreme temperature for a
m i n i m u m of 2 hours. At completion of the 2 hour exposure, and while at -40F,
t h e plotting board shall be freely operable, without binding, when normal
finger pressure is applied to move the deflection arm scale and disk approxi-
mately 360 degrees, in opposition to each other, about the pivot center.
U p o n completion of the low temperature operability test the temperature of
t h e Chamber shall be raised over a period of 8 hours plus or minus 15 minutes,
to +125F. The plotting board shall be maintained at this extreme temperature
f o r a minimum of 2 hours. At completion of the 2 hour exposure and while at
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