6. MAINTENANCE & TROUBLESHOOTING
6-6
6.6
Advanced-level Troubleshooting
This paragraph describes how to cure hardware and software troubles which should be carried
out by qualified service personnel.
Note:
This radar equipment contains complex modules in which fault diagnosis and repair down
to component level are not practicable by users.
Advanced-level troubleshooting
Problem
Probable cause or
check points
Remedy
Power turned on but
radar does not work
1) Blown fuse.
2) Mains voltage/polarity
3) Power supply board
1) Replace blown fuse.
2) Correct wiring and input voltage.
3) Replace power supply board.
Brilliance adjusted
but no picture
1) SPU Board
1) Replace SPU board.
Antenna not rotating
1) Antenna drive mechanism
1) Replace antenna drive mechanism.
Data and marks not
displayed in Transmit
status
1) SPU board
1) Replace SPU board.
Adjust
GAIN
with
SEA
set at minimum.
Marks and indications
appear but no noise
or echo
1) IF amplifier
2) Signal cable between
antenna and processor unit
3. Video amplifier board
1) Replace IF amplifier.
2) Check continuity and isolation of coaxial
cable.
Note:
Disconnect the plug and lugs at both
ends of coaxial cable before checking it (by
ohmmeter).
3) Check coax line for secure connection. If
connection is good, replace SPU board.
Marks, indications
and noise appear but
no echo (Transmis-
sion leak repre-
senting own ship
position is absent)
1) Tx fuse
2) Magnetron
3) Modulator board
4) SPU board
1) If fuse has blown, replace it. If it blows
again, the modulator or associated circuit
may be defective.
2) Check magnetron current.
3) Replace modulator board.
4) Replace SPU board.
Picture not updated
or picture freeze-up
1) Bearing signal generator
2) SPU board
3) Video freeze-up
1) Check that signal cables are fastened
securely.
2) Replace SPU board.
3) Turn the radar off and on.
Radar is properly
tuned but sensitivity is
poor
1) Deteriorated magnetron
2) Detuned MIC
3) Dirt on radiator face
4) 2nd trace echo rejector is
ON.
1) With the radar transmitting on 48 nm
range, check magnetron current. If cur-
rent is below normal, magnetron may be
defective. Replace the magnetron.
2) Check MIC detecting current. If it is below
normal value, MIC may have become
detuned. MIC must be tuned
3) Clean radiator.
4) Turn off the 2nd trace echo rejector, on
the Echo menu.
