Radar troubleshooting, Plotter troubleshooting

8. MAINTENANCE, TROUBLESHOOTING

8.5.2Radar

GD-1720C requires a network radar.

If…	But…		Then…
you pressed the	nothing appears on the	• check that the antenna cable
POWER/BRILL key and the	display		is firmly fastened.
RADAR TX soft key to show		• check if radar source is
the radar picture			correct.
marks, legends appear	no echo appears	• check that the antenna cable
			is firmly fastened.
the picture is not updated or	—	•	check antenna cable.
it freezes		• 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	• try to hit the [+] and [-] keys
	change		again.
		• turn the display unit off and on
			again.
there is poor discrimination in	—	•	adjust A/C SEA.
range
the true motion presentation	—	• reselect true motion mode.
is not working properly		• check if heading and speed
			are input.
the range rings are not	—	• hit the RADAR DISPLY and
displayed			RINGS soft keys to display
			them.

Requires GPS Receiver GP-310B/320B.

	Plotter troubleshooting

If…	Then…
position is not fixed within	• check that antenna connector is firmly fastened.
three minutes	• 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	• check that LORAN C (or DECCA) is selected at TD DISPLAY on the
not appear	GENERAL SETUP menu. Also, check that proper Loran C (Decca)
	chains codes are entered, on the TD SETUP menu.
Loran C (or Decca) TDs	• enter TD offset, on the TD SETUP menu.
are wrong
the ship’s speed indication	• try to decrease speed/course smoothing, on the GPS SENSOR
is not zero after the ship is	SETTINGS menu.
stopped

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