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-6.3-
Problem Probable causes or check
points
Remedy
Antenna not rotating 1 Antenna drive
mechanism (note that
the message BRG SIG
MISSING appears in
standby).
2 Defective antenna
drive motor relay
(thermal relay K2,
200/220/380, 440/100
VAC)
1 Make sure that there is no short circuit
across #1 and #2 of J482 on HV 9017
board.
2 Press relay reset button.
Data and marks not displayed
in Transmit status
1 SPU board 1 Replace SPU board.
Adjust GAIN control with A/C
SEA control set at minimum.
Marks and legends appear but
no noise or echo.
1 IF amplifier
2 Signal cable between
antenna and display
3 Video amplifier board
1 Replace IF amplifier.
2 Check continuously and isolation of
coaxial cable. Note: Disconnect the plug
and lugs at both ends of coaxial cable
before checking it by ohmmeter.
3 Check video coax line for secure
connection. If connection is good,
replace SPU board.
Marks, legends and noise
appear but no echo:
(Transmission leak representing
own ship position is absent.)
1 TX fuse F801
(Transmitter unit)
2 Magnetron
3 Modulator board
4 SPU board
1 If fuse is blown, replace it. If it blows
again, the modulator or associated circuit
may be defective.
2 Check magnetron current with the
check meter in the sub panel. Replace
magnetron.
3 Replace modulator board.
4 Replace SPU board.
Picture not updated or picture
freeze-up.
1 Bearing signal generator
board (in antenna unit)
2 SPU board
3 Video freeze-up
1 Check the connection of signal cables.
2 Replace SPU board.
3 Turn off and on the radar.
Incorrect orientation of picture 1 SPU board
2 Gyro interface
1 HD SIG MISSING appears when the
heading pulse is not received during
standby.
2 Replace the gyro interface.
(Continued on next page)