ELECTRONIC TEST CHAMBER ASSEMBLY, MODEL 453
DIRECT SUPPORT MAINTENANCE
This adjustment is performed in response to a reported defect from user level. The following
procedure is used to correct an out of tolerance condition between the set fall rate and the actual
measured rate. The difference between the set and displayed rates cannot be affected by
All four fall rate combinations; high altitude-high fall rate, high altitude-low fall
rate, low altitude-high fall rate, and low altitude-low fall rate, must be evaluated
together because adjustment of any one of them affects the entire range.
Correct adjustment should bring all of the actual measured rates within 2 ft/sec
of their respective set values. If this cannot be done, the Control Assembly is
defective and must be replaced.
1. Perform fall rate selector accuracy test (refer to WP 0010 00) to determine at which
condition(s) the fall rate is out of tolerance. It is not necessary to place an AR2 in the altitude
chamber for this test, and the JUMP/OFF switch may be left in the JUMP position.
2. Open cover plate on back of control housing. Turn RATE SET resistor screw to adjust the fall
rate (One half turn of the screw in the clockwise direction will lower the actual fall rate by
approximately one ft/sec. The set rate is not affected by the adjustment. There is some
backlash in the movement of the screw; turning past the desired position and coming back to
it may be beneficial).
3. Verify that the actual fall rates are within tolerance at all four conditions.
4. Reassemble cover plate and affix calibration sticker to prevent tampering.
END OF WORK PACKAGE
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