NAVELEX EE 181-AA-OMI-050/E121 DT546 M9442
Section III. GENERAL MAINTENANCE
5-4. MAINTENANCE ACTION. The extent of direct
the Detector. On-site adjustment is made on the gain
control in the Detector and the sensitivity control in the
and general support maintenance is governed by the
Processor. Inspection only is made on the chassis.
Maintenance Allocation Chart (MAC), Appendix B. The
Periodic testing of the Vibration Sensor is not scheduled
MAC provides for on-site test and replacement of the
because the J-SIIDS is maintained in continuous
PC boards in both the Processor and Detector and the
Section IV. REMOVAL AND REPLACEMENT OF MAJOR COMPONENTS AND ASSEMBLIES
5-5. REMOVAL AND INSTALLATION PRO-
Remove screws that secure assembly to
mounting surface, and remove assembly.
To remove the Processor PC board, tag and
To install new pick-up assembly, orient
remove the wires from TB1 and TB2.
assembly so that red and black wires are
Remove screws holding the PC board in the
toward PC board. Tilt assembly so that edge
chassis. Remove the PC board. Note the
nearest PC board can be slipped under PC
position of sensitivity control for reference.
board. Insert assembly into chassis, flat
against mounting surface, and secure it with
To replace the processor PC board, orient
the board so that terminal strips TB1 and TB2
are adjacent to the conduit connections.
After replacement of major components or
Secure the PC board to the chassis with
assemblies during troubleshooting, test the VS
screws. Attach the wires to TB1 and TB2.
for proper operation. Ensure that the key-
Adjust the sensitivity control on the new board
operated switch on the Control Unit is in the
to the same position as on the old board.
Remove the Processor
chassis cover and pull the TAS plunger all the
To remove Detector PC board, tag and
way out. Set multimeter to ohms and connect
disconnect wires from TB1. Disconnect red
leads to TB1-6 and TB1-2. The meter should
and black pick up assembly wires from PC
indicate 2, 000 ohms or less. Slowly open the
board. Remove screws that secure board to
cover on the first Detector. While the cover
chassis. Remove PC board. Note position of
flanges are still engaged, the meter indication
the gain control for reference.
should change to over 100,000 ohms.
Remove the cover. Pull the TAS plunger all
To install new Detector PC board, orient
the way out. The meter indication should
board so the terminal strip is adjacent to the
change to less than 2, 000 ohms. Replace the
conduit entrance hole. Secure the board to
cover. Repeat the test on the remaining
the chassis with screws. Connect wires to
Detectors. Use a straightedge across the
TB1, and connect red and black pick-up
Processor chassis to hold the TAS plunger
assembly wires to the marked terminals on
down. The meter should indicate 2, 000 ohms
the board. Adjust the gain control on the new
or less. Slowly raise the straightedge. After
board to the same position as on the old
the TAS plunger moves 1/4 inch (0.635 cm) or
less, the meter indication should change to
over 100, 000 ohms. Disconnect the wire
To remove pick-up assembly, disconnect red and
from TB1-1. Set multimeter to ohms