Fish Finder Troubleshooting - Furuno TZTL12F Operator's Manual

14. MAINTENANCE, TROUBLESHOOTING
14.4.4

Fish finder troubleshooting

Problem
You selected a fish finder dis-
play, but no picture appears.
Marks and characters appear,
but no picture appears.
Picture appears but zero line
does not appear.
The picture sensitivity is too
low.
The depth indication does not
appear.
Noise or interference shows on
the display.
14-4
• Check that the transducer cable is tightly fastened.
• Check that the fish finder source is correct.
• If you are using a network fish finder, check that it is properly
connected.
Check if the transducer cable is tightly connected.
• The picture is shifted. Check the shift setting.
• Check if the draft setting ([Settings] - [Sounder] - [Transducer
Draft]) is zero or higher.
• If you are in the manual mode, check the gain setting.
• Check the transducer face for marine life and air bubbles.
• Bottom is too soft to return an acceptable echo.
• For manual operation, adjust the gain and range to display the
bottom echo in reddish-brown.
• Adjust the bottom level HF/LF.
• Make sure the transducer cable is not near the engine.
• Check the ground for tight connection, corrosion.
• Check if another fish finder near your boat has the same fre-
quency as your fish finder.
• Try to reject the interference with [Interference Rejection] in the
[Settings] - [Sounder] menu.
Remedy