MD Helicopters 369-500, Maintenance Instructions Manual

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CSP-HMI-3
MD Helicopters, Inc
.
MAINTENANCE MANUAL
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96-00-00
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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
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1999 − 2016 by MD Helicopters, Inc.
(13). Diodes shall be included in continuity
test to ensure correct polarity and
functionality.
(14). Do not include Zener diodes in continu­
ity test. Continuity test shall be made
up to Zener diode termination points.
(15). Transformers shall be included in
continuity test. Add specified trans­
former winding resistance to maximum
resistance allowed.
(16). Manually operated switches and circuit
breakers shall be included in continuity
tests. Perform continuity tests in both
open contact and closed contact posi­
tions.
(17). Electromechanical relays shall be
included in continuity test.
(a). Normally-closed contacts shall show
continuity through circuit.
(b). All other contacts shall show an open
condition in circuit.
(c). Add specified relay coil winding
resistance to maximum resistance
allowed.
(18). Correct discrepancies if found.
(19). If applicable, perform other electrical
tests.
(20). Attach connectors, terminate wired
contacts, and environmentally seal
terminations as required.
(21). Install and secure all access panels
removed.
(22). Restore power to helicopter.
B. Open Circuit Test
Special Tools
(Ref. Section 91 − 00 − 00)
Item Nomenclature
N/A Analog Multimeter, Portable
NOTE:
D
An open circuit test is performed to verify
a wire is not shorted to ground, another
wire, or to a shield.
D
This procedure applies to RF cables.
(1). Verify electrical power is off.
(2). Locate wire harness to be tested.
(3). Remove access panels as required.
(4). Use applicable interconnect diagrams.
(5). Perform Continuity Test procedure.
(6). Use analog multimeter to perform
continuity test on wire.
(a). Set multimeter for continuity test if
applicable, or to measure resistance
(ohms).
(b). Use multimeter leads and any other
adapters to attach to circuitry.
(c). An audible beep or a measurement of
10 ohms or less confirms a short.
(d). A minimum measurement of 500,000
ohms confirms an open circuit.
(7). If wire being tested is non-shielded,
perform the following:
(a). Check for continuity between wire
and common ground.
(b). Check for continuity between wire
and other wires in same harness, or
other suspect wires.
(8). If wire being tested is shielded, perform
the following:
(a). Check for continuity between conduc­
tor and shield.
(b). Check for continuity between wire
and common ground.
(c). Check for continuity between wire
and other wires within same shielded
cable, harness, or other suspect
wires.
(9). If wire being tested is a RF cable,
perform the following:
(a). Check for continuity between contact
and connector.