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
97-06-00
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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.
signal is amplified by the microphone amplifier
in the ICS control unit. (R8 does not affect the
level of received audio signals from any
installed radio equipment.)
(1). Connect headset-microphones at all
radio/ intercom stations.
(2). (Slim-Line instrument panels and RH
command T-panels only) Energize
intercom system by closing NAV/COM
circuit breaker.
(3). (LH command T-panels only) Energize
intercom system by closing AUDIO
circuit breaker.
(4). Adjust R8 until desired headset
earphone volume is obtained in head­
sets while operating intercom system
and speaking into microphone.
NOTE:
If sufficient intercom microphone audio
volume cannot be obtained in headset ear­
phones by adjustment of R8, refer to trou­
bleshooting procedures (Ref. Table 101).
C. VHF COMM Transceiver Sidetone Signal
Level Adjustment
(Ref. Figure 202) COMM 1 and COMM 2
sidetone level control potentiometers R22 and
R25, located on the right end of the ICS
control unit, adjust the level of the side tone
audio from the vhf COMM transmitters that is
applied to headset earphones during vhf
COMM radio transmission. (R22 and R25 do
not affect the level of the microphone audio or
of any received audio signals from any
installed radio equipment.)
(1). Connect headset-microphones at all
radio/intercom stations.
(2). (RH command T-panels only) Energize
intercom system and vhf COMM
radio(s) by closing NAV/COM circuit
breaker.
(3). (Slim-Line instrument panels only)
Energize intercom system and vhf
COMM radio(s) by closing NAV/COM,
COMM 1 and/or COMM 2 circuit
breakers.
(4). (LH command T-panels only) Energize
intercom system and vhf COMM
radio(s) by closing AUDIO, COMM 1
and/or COMM 2 circuit breakers.
(5). Select the desired radio using the
COMM 1-XMIT-COMM 2 switch, prior
to transmitting.
(6). While transmitting with vhf COMM
radio No. 1 (or COMM radio No. 2),
adjust R22 (or R25) for desired sidetone
audio volume in headset earphones.
NOTE:
If sufficient sidetone audio volume can­
not be obtained in headset earphones by ad­
justment of R22 and R25, refer to trouble­
shooting procedures (Ref. Table 101).
D. Intercom Phone Audio Level Adjustment
(1). Connect a headset-microphone at any
radio/intercom station.
(2). (Slim-Line instrument panels and RH
command T-panels only) Energize
intercom system by closing NAV/COM
circuit breaker.
(3). (LH command T-panels only) Energize
intercom system by closing AUDIO
circuit breaker.
(4). Check that earphone audio level is
correctly adjusted for all other radio
communication equipment that may be
installed.
(5). Recheck and readjust vhf COMM
transmitter sidetone level as necessary
(Ref. Integrated Interphone Communi­
cation System Troubleshooting).
3. Integrated Interphone Communication
System Inspection
(Ref. Figure 201 and Figure 202) Inspect
integrated interphone communication system's
components in accordance with FAA AC
43.13-1A and aircraft standard electrical
repair and replacement practices and proce­
dures, noting the following:
Ensure that all electrical power
to system is OFF.
(1). Examine wiring harnesses for damage;
and wire terminals and terminal boards
for security of attachment.
(2). Examine ICS control unit for good
electrical bond to instrument console
CAUTION