Northern Airborne Technology 806 - Manual (Page 12)

806 and 807 Audio Selector Panels
SM806 Installation and Operation Manual
Section 2 Rev: 1.00 Issue 4 Page 2-2
ENG-FORM: 805-0115.DOT
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.
2.4.2 Cautions
CAUTION:
In all installations, use shielded cable exactly as shown and ground as
indicated. Significant ground loop and noise problems may result from not
following these guidelines. Check that the chassis is grounded to provide
proper shield terminations.
Check that the microphone and headphone jacks are isolated from the
airframe ground. Use caution when routing microphone wiring, as it carries
low-level signals prone to coupling from other sources.
Do not take a ground from the instrument panel or similar location that shares
a ground return with a turn and bank, horizon or other motor driven
instrument. This may cause the unit to pick up the sound of the motor as
ground loop interference.
2.4.3 Cabling and Wiring
All wire shall be selected in accordance with the original aircraft manufacturer's Maintenance Instructions
or AC43.13-1B Change 1, Paragraphs 11-76 through 11-78. Unshielded wire types shall qualify 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 connector map in
Section 2.7 as required.
Allow 3" from the end of the shielded wiring to the shield termination to allow the connector hood to be
easily installed. Reference the interconnect drawing in Section 2.7 for shield termination details. Aircraft
harnessing shall 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 performed.
Maintain wire segregation and route wiring in accordance with the original aircraft manufacturers
Maintenance Instructions.
Unless otherwise noted, all wiring shall be a minimum of 24 AWG, except power and ground lines, which
shall be a minimum of 22 AWG. Reference the Interconnect drawing for additional specifications.
Check
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 circuit breaker or fuse (fast blow), and not attached to any other circuit
breaker without additional protection. Verify that the selected circuit breaker size and wire gauge are
adequate for the installation using the techniques specified in AC43.13-1B Change 1, Paragraphs 11-47
through 11-51 and 11-66 through 11-69.
2.4.4 Mounting
No shock or vibration isolators are required for mounting. The unit should be mounted to a metal surface
and grounded to the aircraft ground structure. The unit and mounting surface is finished with an
electrically conductive film, which should not be removed for electrical bonding to any metal aircraft
ground structure because the coating prevents corrosion. The 806 is mounted using 4 captive 6-32
screws, and the 807 is mounted using 3 captive 6-32 screws, which are supplied with the unit as part of
the enclosure front panel assembly.