8. MAINTENANCE, TROUBLESHOOTING
8-4
8.5.2 Radar
GD-1720C requires a network radar.
Radar troubleshooting
If… But… Then…
you pressed the
POWER/BRILL key and the
RADAR TX soft key to show
the radar picture
nothing appears on the
display
• check that the antenna cable
is firmly fastened.
• check if radar source is
correct.
marks, legends appear no echo appears
• check that the antenna cable
is firmly fastened.
the picture is not updated or
it freezes
—
• check antenna cable.
• for freeze up, turn the display
unit on and off again.
tuning is adjusted sensitivity is poor
• magnetron may need to be
replaced. Contact your dealer.
the range is changed radar picture does not
change
• try to hit the [+] and [-] keys
again.
• turn the display unit off and on
again.
there is poor discrimination in
range
—
• adjust A/C SEA.
the true motion presentation
is not working properly
—
• reselect true motion mode.
• check if heading and speed
are input.
the range rings are not
displayed
—
• hit the RADAR DISPLY and
RINGS soft keys to display
them.
8.5.3 Plotter
Requires GPS Receiver GP-310B/320B.
Plotter troubleshooting
If… Then…
position is not fixed within
three minutes
• check that antenna connector is firmly fastened.
• check number of satellites received, on the GPS status display. (See
page 8-11.) There should be three or more.
position is wrong
• check that the correct geodetic chart system is selected, on the GPS
SENSOR SETTINGS menu.
• enter position offset, on the GPS SENSOR SETTINGS menu.
the track is not plotted
• track is not being plotted. (“H” icon appears at the top of the display.)
Press the TRACK HALT soft key on the TRACKS & MARKS
CONTROL menu to start plotting again.
the bearing is wrong
• check that correct magnetic variation is entered, on the GENERAL
SETUP menu.
Loran C (or Decca) TDs do
not appear
• check that LORAN C (or DECCA) is selected at TD DISPLAY on the
GENERAL SETUP menu. Also, check that proper Loran C (Decca)
chains codes are entered, on the TD SETUP menu.
Loran C (or Decca) TDs
are wrong
• enter TD offset, on the TD SETUP menu.
the ship’s speed indication
is not zero after the ship is
stopped
• try to decrease speed/course smoothing, on the GPS SENSOR
SETTINGS menu.