MD Helicopters 369-500, Maintenance Instructions Manual

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CSP-HMI-3
MD Helicopters, Inc
.
MAINTENANCE MANUAL
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Revision 12
97-08-00
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. Loudspeaker Replacement
(Ref. Figure 201)
(1). Verify BATTERY-OFF-EXT PWR
switch at OFF position.
(2). Disconnect wire harness assembly from
loudspeaker at drive unit.
(3). Loosen and remove setscrew securing
horn nut to threaded end of horn.
(4). Loosen horn nut, and remove driver
unit, horn, and spacers from mounting
bracket.
(5). Repeat steps (2). thru (4). for removal of
remaining loudspeaker assembly.
(6). Install threaded end of horn through
attachment hole in mounting bracket;
then attach driver unit and spacers to
threaded end of horn.
(7). Position driver unit as required and
secure to mounting bracket with horn
nut.
(8). If required, use drill motor and appro­
priate drill bit to provide hole for
setscrew in threaded end of horn as
follows:
(a). Use horn nut as template.
(b). Drill 0.1405 in. (3.5687 mm) hole in
horn casting.
(c). Tap hole for setscrew.
(9). Secure horn nut in place with setscrew.
Torque setscrew to 6 inch-pounds
(8.14 Nm) .
(10). Connect -19 wire harness assembly to
loudspeaker at drive unit.
(11). Perform Operational Check of system.
C. Control Unit and Microphone
Replacement
(Ref. Figure 201)
(1). Verify BATTERY-OFF-EXT PWR
switch at OFF position.
(2). Remove microphone from holder and
disconnect microphone cord from aft
side of control unit at connector P562.
Retain microphone for installation.
(3). Disconnect wire harness assembly from
aft side of control unit at connector
P561.
(4). Loosen and remove screws and washers
from support. Remove support and
control unit from right side fairing of
instrument panel.
(5). Prepare replacement control unit as
follows:
NOTE:
A good structural electrical bond
(ground) must exist between control unit,
support, and instrument console structure.
(a). Remove screws securing support on
control unit. Discard screws.
NOTE:
Detached control unit support has at­
tached microphone holder.
(b). Install support on replacement
control unit, using screws supplied
with unit.
(6). Using washers and screws, secure
control unit and support to right side
fairing on instrument panel structure.
(7). Connect wiring harness assembly to aft
side of control unit at connector P561.
(8). Connect microphone cord to aft side of
control unit at connector P562. Stow
microphone on holder.
(9). Perform Operational Check of system.
D. Circuit Breaker Replacement
(Ref. Figure 201)
(1). Verify BATTERY-OFF-EXT PWR
switch at OFF position.
(2). Remove PA SYS circuit breaker from
lower switch and circuit breaker panel
as follows:
(a). Remove screws and lower switch and
circuit breaker panel from instru­
ment panel for access to PA SYS
circuit breaker.