Northern Airborne Technology AMS42 - Manual (Page 20)

SM19 Rev 4.00 AMS42/44 Dual Channel Audio Controller Manual
Page 2-2 Nov 21, 2003
ENG-FORM: 805-0102.DOT
Amendment #2 Feb 15, 2005
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.
All audio installations can be seriously degraded by incorrect wiring and shielding, and
may result in abnormal cross-talk, hum and ground-loop noise. Be especially careful
with all microphone wiring and Tie Line wiring, as these lines carry the lowest level
signals in the aircraft.
All microphone and headset jacks should be electrically isolated from the airframe or
significant ground loop noise may result.
Failure to follow the installation and wiring instructions provided in this manual for power
and ground connections, including the rating of the circuit breaker, may lead to damage
in the power input circuitry of the unit.
2.4.3 Cable and Wiring
All unshielded wire shall be selected in accordance with AC43.13-1B Change 1,
Paragraphs 11-76 through 11-78. Wire types should be to MIL-W-22759 as specified in
AC43.13-1B Change 1, Paragraphs 11-85, 11-86, and listed in Table 11-11. For
shielded wire applications, use Tefzel MIL-C-27500 shielded wire with solder sleeves
(for shield terminations) to make the most compact and easily terminated interconnect.
Follow the wiring diagrams in Section 2.6 as required.
Allow 3" from the end of the wire to the shield termination to allow the connector hood to
be easily installed. Note that the hood is a "clamshell" hood, and is installed after the
wiring is complete. Aircraft harnessing should permit the unit to be lowered from the
panel for easy access to all side adjustments. Do NOT mount the unit until all
adjustments have been carried out.
All wiring should be at least 24 AWG, except power and ground lines, which should be
at least 20 AWG. Ensure that the ground connection is clean and well secured, and
that it shares no path with any electrically noisy aircraft accessories such as blowers,
turn and bank instruments or similar loads. Power to this unit must be supplied from a
separate breaker (1 Amp) or fuse (1 Amp fast blow), and not attached to any other
existing breaker without additional protection.
Before the unit is mounted, make all functional tests and trimpot adjustments. Be sure
the harness has enough clearance to permit the unit to be dropped down for re-
adjustment, if needed later. Make sure that the connector locks are tightened, and the
unit is securely fastened to the panel before any flight is attempted.
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
top and sides of the unit, and are as follows: