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2.3.3
Cautions
Use shielded cable exactly as shown and ground as indicated. All audio installations can be severely
degraded by incorrect wiring and shielding.
symptomatic of multiple grounds, or noisy external systems such as blowers or pumps sharing wiring with
the audio system. Never operate any of these units below their 8 rated impedance.
2.3.4
Cabling 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 inches from the end of the wire to the shield termination to allow the hood to be easily installed. Note that the
hood is a 'clamshell' hood, and is installed after the wiring is complete.
All wiring should be at least 22 AWG, except power and ground lines, which should be at least 20 AWG.
Ensure that all ground connections are clean and well secured. To prevent system failure or inadequate
equipment protection, power must be supplied from a separate breaker or fuse and not connected to any
other source.
2.3.5
Post-Installation Checks
2.3.5.1
Voltage/resistance checks
Do not attach the AA21-400 until the following conditions are met.
Check the following:
a)
P101 pins <1> <2> and <3> for +28 Vdc relative to ground.
P101 pins <14>, <15> and <16> for continuity to ground (below 0.5 ).
b)
c)
P101 pins <18>, and <22> (with switches open) for infinite resistance to ground (> 10 M).
P101 pin <5> to pin <7> for 4 – 6 (typical).
d)
2.3.5.2 Power On checks
The AA21-400 is a high power device, capable of producing tones at very high
volume levels. Ensure that all personnel are well clear of the aircraft prior to
keying the siren or PA. Failure to adhere to this warning could cause injury to
personnel and/or damage to equipment. DO NOT conduct the following tests
inside an enclosed area (i.e. a hangar.)
Build Standard: 5.00
ENG-FORM: 805-0100.DOTX
CONFIDENTIAL AND PROPRIETARY TO ANODYNE ELECTRONICS MANUFACTURING CORP.
AA21-400 Cabin PA System
SM34 Installation and Operation Manual
Unusual buzzes, hums or other background audio are
WARNING
Nov 09, 2016
Page 2-2
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