RADIOBEACON TRANSMITTER
ND500II (125 WATTS) DOUBLE SIDEBAND - NO VOICE
Page 6-1
15 September 2003
SECTION 6
MAINTENANCE
GENERAL
6.1
This section contains scheduled and
corrective maintenance information for the subject
transmitter. Fault symptoms should be analyzed to
determine the corrective action required. Normally,
faults will be isolated to an assembly or printed
wiring board, which is then removed from the exciter
and repaired. Replacement of the defective assembly
with a serviceable assembly is another method of
restoring the transmitter to an operational status. In
any event, the most practical way to isolate a fault is
to perform a minimum performance test and attempt
the appropriate calibration procedures when a test
requirement is not obtained. This section contains
wiring information for each hard wired assembly. It
also contains a listing of the mechanical drawings,
provided in the foldout section. These drawings
depict the assembly detail and identify electrical parts
by their assigned reference designation. They also
provide information regarding the location and
marking of all controls and indicators.
ELECTRICAL SCHEMATICS/ LOGIC
DIAGRAMS
6.2
An electrical schematic and/or logic
diagram, as appropriate, for each electrical assembly
and/or printed wiring board is provided.
6.2.1
COMPONENT VALUES:
Unless
otherwise specified on the schematic:
-
All resistor values are shown in ohms (K=1,000
and M = 1,000,000)
-
All capacitor values are shown in microfarads
(uF)
-
Unidentified diodes are part number 1N4938
6.2.2
GRAPHIC SYMBOLS:
The graphic
symbols used on the electrical schematics are in
accordance with American National Standard ANSI
Y32.2-1975 - Graphic Symbols for Electrical and
Electronic Diagrams.
6.2.3
LOGIC SYMBOLS
: The logic symbols
used on electrical schematics and logic diagrams are
in accordance with American National Standard
ANSI Y32.14-1975 - Graphic Symbols for Logic
Diagrams.
6.2.4
REFERENCE DESIGNATIONS:
Reference designations are assigned in accordance
with American National Standard ANSI Y32.16-
1975 - Reference Designations for Electrical and
Electronic Parts and Equipments. Each electrical
symbol is identified with its basic reference
designation. To obtain the full reference designation
for a specific part, this basic identifier must be
prefixed with the reference designation assigned to all
higher assemblies.
SCHEDULED MAINTENANCE
6.3
Scheduled maintenance comprises
performing a visual inspection of the subject
transmitter in conjunction with a calibration/
minimum performance test (see section 5) at
scheduled intervals. The recommended minimum
time between scheduled maintenance visits is one
year. Local operating and environmental conditions
may dictate more frequent visits and, in the case of
remote sites, less frequent visits may be acceptable.
Experience and system reliability will determine the
most practical schedule for a specific installation.
CORRECTIVE MAINTENANCE
6.4
Corrective maintenance procedures
comprise identifying and correcting defects or
deficiencies that arise during operation and/or
calibration and testing of the transmitter. The
transmitter will shut down automatically if the carrier
level or modulation depth fall below preset thresholds
or if the identification code keying is lost. Alarm
lamps that are associated with the fault that caused
the transmitter to shut down will turn on when the
transmitter is reset. A minimum performance test
and where appropriate an attempted calibration
procedure should be the first step in taking corrective
action.
