Northern Airborne Technology AA224 series, Installation And Operation Manual

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SM18 Rev. 4.00 AA24/AA25 Series Single User Audio Controller Manual
The Direct Audio level (
DIR AUD LEVEL ) and sidetone level ( S/T LEVEL ) can be
adjusted at the time of installation. The adjustment pots are accessed through holes in
the upper cover, and can be rotated clockwise to increase the level, and
counterclockwise to decrease it.
2.3.6 Post-Installation Checks
2.3.6.1 Voltage/resistance checks
Do not attach the AA24 or AA25 until the following conditions are met.
Check the following:
a) Check J101, pin <1> for +28 Vdc relative to ground.
b) Check J101, pin <9> for continuity to ground (less than 0.5
Ω
).
2.3.6.2
Power On checks
Install the AA24 or AA25 and power up the ship’s systems. Verify normal operation of
all functions. Refer to Section 3 for specific operation details.
a) Run through all installed functions, and check the ICS and TX functions for all users.
b)
Different headsets models may have significantly different mic characteristics,
which will affect ‘VOX’ squelch settings. The David Clark M-7 mic is much more
active than the M-4 or M-1 mics, and may aggravate headset imbalance if used
in a mixed system.
Note : Unusual buzzes, hums or other background audio are symptomatic of
multiple grounds, or noisy external systems such as blowers or pumps
sharing wiring with the audio system. Failure to key or correctly modulate
a transmitter is often the result of forgetting to connect all required
grounds to the radio or external audio system.
c)
To verify proper operation, all functions and levels should be checked in-flight.
If the unit functions satisfactory, make the required log entries and complete the
required MOT/FAA paperwork, before releasing the aircraft for service.
2.4 Continued Airworthiness
Maintenance of the AA24-001 or AA25-001 Single User Audio Controller is ‘on
condition’ only. Periodic maintenance of this product is not required.
Nov 21, 2003 Page 2-3
ENG-FORM: 805-0105.DOT
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.