Northern Airborne Technology AMS43 - Manual (Page 10)

AMS43 Single Channel Audio Controller
SM59 Installation and Operation Manual
Section 2 Rev: 1.00 Issue 4 Page 2-3
ENG-FORM: 805-0116.DOT
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.
2.4.4.1 Voltage/Resistance Checks
Do not attach the AMS43 until the following conditions are met.
Check the following:
a) P101 pins <16> and <17> for +28 Vdc relative to ground.
b) P101 pin <34> for continuity to ground (below 0.5
Ω).
c) P102 pin <19> for +28 Vdc lights bus voltage.
d) Check all Mic, phone, music and key lines for shorts to ground or adjacent pins.
2.4.4.2 Power On Checks
Power up the aircraft’s systems and confirm normal operation of all functions of the AMS43. Refer to
Section 3 (Operation) for specific operational details.
Start with only the pilot's headset installed. Check for correct Intercom (ICS), radio, and transmit (TX)
operation. Do not proceed until the radios are functioning correctly. The S/T 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 receive (RX) levels should be set first with the AMS43 in PILOT
ISO/EMR (Pilot isolate/emergency) mode, then adjust the AMS43 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. 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 and test for correct operation. 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 and check for proper operation. An incorrect 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 2.5.3 below.
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 all required log book entries, electrical
load, weight and balance amendments and other documentation as required by your local regulatory
agency before releasing the aircraft for service.
2.5 Adjustments and Connections
The unit ships from the factory with all internal adjustments set to the normal test levels. Once installed in
the aircraft, it may be desirable to change some of these settings to best suit the local operating
environment.
The internal adjustments are located on the sides of the unit and are as follows: