Furuno GP-3500F - Manual (Page 223)

12. MAINTENANCE & TROUBLESHOOTING
12-5
Sounder troubleshooting
If… Then…
● check that “7. STOP” is not selected of the
PICTURE ADVANCE on the ECHO SOUNDER
SETUP menu.
picture does not move though marks and
characters appear
● check for loosened transducer connector.
zero line does not appear though the picture
appears
● the picture is shifted. Confirm shift setting.
● check gain setting, if using manual operation.
● marine life or air bubbles may be clinging to
transducer face. picture sensitivity is too low
● bottom may be too soft to return a suitable
echo.
the depth indication is not displayed
● adjust gain and range to display the bottom
echo in reddish brown, if you are using the
manual operation.
● If no noise appears after turning the engine off,
the engine interference is suspected. Call your
dealer.
● check the ground.
noise or interference shows on the display
● other video sounder of the same frequency as
yours may be operating near you.
data is wrong though the water temperature
graph appears.
● check that sensor cable is tightly fastened.