Furuno GP-1670F Operator's Manual page 131

Problem
The speed indication
is not zero after the
ship is stopped.
Fish Finder Troubleshooting
You selected a fish
finder display, but no
picture appears.
Marks and charac-
ters appear, but no
picture appears.
Picture appears but
zero line does not
appear.
The picture sensitivi-
ty is too low.
The depth indication
does not appear.
Noise or interference
shows on the dis-
play.
12. MAINTENANCE, TROUBLESHOOTING
Set [NAVIGATION SPEED] to [Low] in the [INTERNAL GPS
SETUP] in the [SYSTEM] menu.
• Check that the transducer cable is fastened.
• Check if the fish finder source is correctly selected.
Check that the transducer cable is connected.
• The picture is shifted. Check the shift setting.
• Check if [ZERO LINE REJECTION] in the [FISH FINDER]
menu is off.
• Check the gain setting in manual operation.
• Check if marine life or air bubbles are on the transducer.
• Bottom is too soft to return an acceptable echo.
• For manual operation, adjust gain and range to display the bot-
tom echo (in reddish-brown).
• Adjust the bottom level.
• Check if [DEPTH] in the [SELECT INPUT DEVICE] menu in
the [INTERFACE] menu is set to [Fish Finder].
• Make sure the transducer cable is not near the engine.
• Check the ground connection.
• Check if another fish finder in the vicinity of your boat has the
same operating frequency as your fish finder.
• Try to adjust the interference rejector.
Remedy
12-3