MD Helicopters 369-500, Maintenance Instructions Manual

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CSP-HMI-3
MD Helicopters, Inc
.
MAINTENANCE MANUAL
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97-08-00
Page 207
Revision 12
The information disclosed herein is proprietary to MD Helicopters, Inc.
Neither this document nor any part hereof may be reproduced or transferred to
other documents or used or disclosed to others for manufacturing or any other
purpose except as specifically authorized in writing by MD Helicopters, Inc.
Copyright
©
1999 − 2016 by MD Helicopters, Inc.
(b). Tag and disconnect wiring from PA
SYS circuit breaker at terminals
CB129-1 and CB129-2 and remove
circuit breaker from panel.
(3). Install PA SYS circuit breaker on lower
switch and circuit breaker panel as
follows:
(a). Install PA SYS circuit breaker on
panel and connect wiring to circuit
breaker terminals CB129-1 and
CB129-2.
(b). Install and secure lower switch and
circuit breaker panel to instrument
panel with screws.
(4). Perform Operational Check of system.
E. Electrical Wiring Harness Replacement
(Ref. Figure 202)
Consumable Materials
(Ref. Section 91 − 00 − 00)
Item Nomenclature
CM704 Tie strap, nylon
The electrical wiring for the public address and
siren system consists of a power input wire
harness (-15 assembly), control unit input
wire harness (-17 assembly), and loudspeaker
output wire harness (-19 assembly). Refer to
Figure 202 for detailed wiring diagram,
assembly connectors, and individual wire and
connector data.
(1). Verify BATTERY-OFF-EXT PWR
switch at OFF position.
(2). Disconnect power input wire harness
(-15 assembly) from amplifier at
connector P558, from PA SYS circuit
breaker terminal CB129-2 and from
helicopter ground at TB6-4. Disconnect
nylon tie straps (CM704) and remove
wire harness assembly.
(3). Disconnect control unit input wire
harness (-17 assembly) from amplifier
at connector P559, and from control
unit at connector P561. Disconnect
nylon tie straps (CM704) and remove
wire harness assembly.
(4). Disconnect loudspeaker output wire
harness (-19 assembly) from amplifier
at connector P560, and loudspeaker
connectors LS(DS)1 and LS(DS)2.
Disconnect wire TD4A14 at loudspeak­
er connector LS(DS)1-L1 and
LS(DS)2-L2. Disconnect nylon tie
straps (CM704) and remove wire
harness assembly.
(5). Install wire harness assemblies (-15,
-17 and -19) in reverse order of
removal, steps b. through d., and secure
as required with nylon tie straps
(CM704).
(6). Perform Operational Check of system.
5. Operational Check
With helicopter on ground, perform Operation­
al Check of public address and siren system as
follows:
(1). Place BATTERY-OFF-EXT PWR
switch at BATTERY position. Verify PA
SYS circuit breaker on lower circuit
breaker and switch panel is engaged.
(2). On control unit panel, place selector
knob for public address system at ON
position.
(3). Using microphone removed from top of
control unit, check operation of public
address system. Position selector knob
as required for desired audio control.
(4). Verify that both loudspeakers are in
operation.
(5). Place siren selector knob in on position.
check siren operation in yelp or curdler
positions on adjacent selector knob:
then place siren selector knob in OFF
position.
(6). Place selector knob for public address
system at OFF position. Stow micro­
phone on top of control unit.
(7). Place BATTERY-OFF-EXT PWR
switch at OFF position.