Northern Airborne Technology AMS43 TSO - Manual (Page 10)

AMS43 TSO Single Channel Audio Controller
SM27 Installation and Operation Manual
Section 2 Rev: 1.00 Issue 4 Page 2-3
ENG-FORM: 805-0121.DOT
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.
2.4.4 Post-Installation Checks
2.4.4.1 Voltage/Resistance Checks
Do not attach the AMS43 TSO 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 keylines 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 TSO. Refer to
Section 3 (Operation) for specific operational details.
a) Start with only the pilot's headset installed. 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, and then the front panel RX master volume control.
b) 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.
c) Plug in the hand mic and test for correct operation. 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.
d) Plug in the remaining headsets and check for proper operation. Note that 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.
e) To verify proper operation, all functions and levels should be checked in-flight.
f) Check that preset adjustments are completed before aircraft departure.
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: