TM 10-1670-305-23&P DESCRIPTION AND USE OF CONTROLS AND INDICATORS 0007  00 KEY CONTROL OR INDICATOR FUNCTION OR USE 12 JUMP SWITCH ON indicator This indicator remains steadily illuminated whenever the AR2 JUMP/OFF switch is in the fully JUMP position.  Its color, green, matches that on the AR2 JUMP/OFF switch and signifies that the AR2 is prepared for the test.   The FALL switch will not function unless this indicator is illuminated.  Once the fall has been initiated, however, the JUMP/OFF switch may be returned to the OFF position without affecting the test.  The AR2 will not actuate with the JUMP/OFF switch OFF. 13 HOLD DOWN TO SET switch When this switch is depressed, the displays show the altitude and fall rate to which the chamber has been adjusted.  As long as the button is held down, the values displayed on the meters are the set values.  When the button is released, the meters display the presently existing chamber conditions.  This switch will function at any time (even during a fall) except when the displays are locked. 14 SET VALUES DISPLAYING indicator This indicator blinks continuously only while the HOLD DOWN TO SET switch is depressed. 15 DUMP switch Pressing this switch vents the chamber to rapidly return to ambient altitude.  This switch has a latching mechanism which keeps it locked in the on (CHAMBER VENTED) position until it is pressed again. 16 CHAMBER VENTED indicator This indicator blinks continuously whenever the DUMP circuit is engaged. 17 RESET DISPLAYS switch This switch clears the values locked into the displays from the previous actuation.  To prevent inadvertent loss of data, the switch will not function until after the AR2 has been recocked. 18 DISPLAYS LOCKED indicator This indicator becomes illuminated at the instant the AR2 actuates and blinks continuously while the displays are in the locked condition.  It goes out when the RESET DISPLAYS switch is pressed, provided the correct conditions are present to reset the meters. 19 FALL RATE (FT/SEC) display     This indicator displays fall rate. 20 ALTITUDE (FT MSL) display This indicator displays altitude. 21 ON/OFF switch Use to turn unit ON and OFF. 22 Fuse, 5 AMP, slow blow Protects circuitry in Control Assembly. 23 Calibration port Use to connect calibration standard to control assembly. 24 Identification decal Identifies Model 453 Electronic test chamber Assembly. 25 Control Assembly decal Identifies control assembly and adjustment screws. 26 Control Assembly Contains testing control components. 27 Lifting Handle Use to lift test chamber. 0007  00-7/8 Blank Change 1