Furuno GP-3700F Operator's Manual page 194

13. MAINTENANCE, TROUBLESHOOTING
Track for own ship is not plot-
ted.
Loran (or Decca) TDs are not
displayed.
Loran (or Decca) TDs are
wrong.
Bearing is wrong.
The ship's speed indication is
not zero after the ship is
stopped.
Data from NMEA2000 equip-
ment are not received.
AIS target without heading data
points true north always.
Picture does not move, al-
though marks and characters
appear.
Zero line does not appear al-
though the picture appears.
Picture sensitivity is too low.
Depth indication is not dis-
played.
Noise or interference appears
on the display.
Data is wrong although the wa-
ter temperature graph appears.
13-4
Symptom
Echo sounder troubleshooting
Symptom
Remedy
• Check that [DISP. STOPPED TRACKS] in the
[MARK/TRACK SETTING] menu is set to [SHOW].
• Check that [DISPLAY TRACKS] in the [MARK/
TRACK SETTING] menu is set to [SHOW].
Check the Loran or Decca chain number on the
[PLOTTER DISPLAY SETTING] - [LORAN/DECCA
SETTING] menu.
Correctly enter TD offset on the [PLOTTER DISPLAY
SETTING] - [LORAN/DECCA SETTING] menu.
Check the [MANUAL MAG. VAR.] setting in the [SYS-
TEM SETTING] - [DISPLAY FORMAT] menu.
Try to decrease the setting for [SPEED AVERAGING]
in the [SYSTEM SETTING] - [NAVIGATOR SETUP]
menu.
Turn on the NMEA2000 network power first. If the
GP-3700F power is turned on first, restart it.
Check the course by displaying the AIS target data
(see section 12.4.1).
Remedy
• Check that the picture advance setting in the
[ECHO SOUNDER SETTING] menu is set to other
than [STOP PICTURE ADVANCE].
• Check if the transducer cable is tightly connected.
Check if the picture is shifted.
• Check gain setting if in manual operation.
• Marine life or air bubbles may be adhering to the
transducer face.
• Bottom echo may be too soft to return a suitable
echo.
Adjust gain and range settings to display the bottom
(in reddish brown), if in manual operation.
• Turn off engine. If noise disappears suspect engine
noise. Contact your dealer for advice.
• Check the ground for tight connection, rust.
• Other sounder of the same frequency as yours may
be in the vicinity.
Check if the sensor cable is firmly tightened.