Northern Airborne Technology AA95-766 - Manual (Page 14)

AA95-766 Single Channel Audio Controller Manual SM95-766 Rev. 2.00
2.3.6.2
Power On Checks
Power up the aircraft's system with the unit installed, and turn on the radios and
accessories required for the system. Refer to Section 3 for operation and set-up
information.
Start with only the pilot's headset installed (lo-z mic, hi-z phones). Check for correct ICS,
radio, and transmit operation. Do not proceed until the radios are functioning correctly.
The S/T (sidetone) trimpot accessible through the left side of the controller and the
transceiver internal trimpot may have to be adjusted for correct balance for the pilot.
Adjustment of the individual radio RX levels should be set first with the AA95-766 in Pilot
ISO mode, then adjust the AA95-766 front panel RX master volume control level in
NORMAL mode.
Unusual buzzes, hums or other background audio are symptomatic of multiple grounds
or noisy external systems sharing the same wire bundle. Note that incorrect jack wiring
is a common fault, especially for passenger stations, and may cause loss of audio, a
tone on the headset lines, or other problems. Failure to key or correctly modulate a
transceiver may be caused by missing grounds on the radio or audio controller.
Plug in the hand mic (if installed) and test for correct operation. (Hand mic activation
does not illuminate the TX light.) Note that wiring faults for this accessory may cause
peculiar loss of ICS or TX functions because it has over-riding priority in the system.
Plug in the remaining headsets (hi-z mic, hi-z phones) and check for proper operation.
Note that an incorrect cordset (drop cord) or improper jack wiring may cause a wide range
of problems from loss of audio to a tone heard in the headset. For further information,
see section 2.3.7 below.
Note: Different headsets may have significantly different mic characteristics, which will
affect VOX squelch settings.
Check levels and operation of all functions in flight to ensure proper adjustments and
settings have been made.
Upon satisfactory completion of all performance checks, make the required log
entries and complete the necessary Regulatory Agency paperwork before
releasing the aircraft for service.
2.3.7 In-line PTT Cordsets
2.3.7.1 General
In-line, push-to-talk (PTT) cordsets (also known as drop cords) can be used to
create/provide PTT capability for the user headsets that do not have yoke or cyclic
mounted PTT switches. For headsets connected to the PILOT or COPILOT
inputs/outputs, ICS and TX keylines are needed to properly activate the associated PTT
circuitry inside the AA95-766. For headsets connected to the PASSENGER
Page 2-4 Dec 6, 2004
ENG-FORM: 805-0106.DOT
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