10. MAINTENANCE, TROUBLESHOOTING
10-5
10.5 Advanced-level Troubleshooting
This section describes how to cure hardware and software troubles which the qualified
service persons must do.
Advanced-level troubleshooting
Problem
Probable cause or check
points
Remedy
Power cannot be
turned on.
1) Mains voltage/polarity
2) Power supply board
1) Correct the wiring and input
voltage.
2) Replace power supply
board.
Brilliance adjusted
but no picture.
1) SPU Board 1) Replace SPU board.
Antenna not rotat-
ing.
1) Antenna drive mechanism 1) Replace the antenna drive
mechanism.
Data and marks
not displayed in
transmit.
1) SPU board 1) Replace SPU board.
Set [GAIN] to max-
imum with [SEA]
set at minimum.
Marks and indica-
tions appear but no
noise or echo.
1) Signal cable between an-
tenna and display unit
2) IF amplifier
3) Video amplifier board
1) Check continuity and isola-
tion of coaxial cable.
2) Replace IF amplifier.
3) Check coax line for fasten
connection. If connection is
good, replace SPU board.
Marks, indications
and noise appear
but no echo.
(Transmission leak
representing your
ship position is ab-
sent.)
1) Magnetron
2) Modulator board
3) SPU board
1) Check magnetron current.
2) Replace modulator board.
3) Replace SPU board.
Picture not updat-
ed or picture
freeze-up.
1) Bearing signal generator
2) SPU board
3) Video freeze-up
1) Check that signal cables
are fastened.
2) Replace SPU board.
3) Turn off and on the radar.
Radar is correctly
tuned but sensitivi-
ty is poor.
1) Dirt on radiator face
2) Deteriorated magnetron
3) Detuned MIC
1) Clean radiator.
2) Check the magnetron cur-
rent with the radar transmit-
ting on 48 nm range. If the
current is below normal,
magnetron may be defec-
tive. Replace the magne-
tron.
3) Check MIC detecting cur-
rent. If MIC detecting cur-
rent is below normal value,
MIC may have become de-
tuned.
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