How to Repair a Humminbird Fish Finder

How to Repair a Humminbird Fish Finder

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Humminbird fish finders locate underwater obstacles, fish, and identify the water bottom surface. The devices use a display screen and a transducer. The transducer attaches to the bottom of the boat and bounces sonar waves under the boat. The transducer receives the waves as they bounce back and transfers the information to the display screen. If you have a Humminbird that is malfunctioning, use Humminbird's troubleshooting tips to repair it and get it back up and running.

Items you will need

  • Can of compressed air

  • Sponge with warm water

  • Chamois cloth

Turn the Humminbird unit on. If the fish finder does not power up, check the cable connections. Inspect the cable for frays or tears. If present, remove the cable by unplugging the cable from the display screen and disconnecting the cable from the power source. Push the cable into the connections to ensure the fits are snug and power the unit on.

Check that the fuse for the device is in working order. Check the boat's fuse box and look for any blown fuses. If present, replace. Check that the red and black cables are connected to the red and black battery terminals respectively.

Check the display screen for white noise. This is caused by an improperly placed transducer. To fix, locate the transducer on the bottom of the boat. If the transducer is too close to the engine or the propellers noise is created. This is due to the propeller's cavitation creating air bubbles in the water.

Remove the transducer, either by unscrewing the mounts or by prying off the unit and breaking the epoxy seal. Move the transducer to a spot near the middle of the boat's hull and glue it or screw it into position. Check the screen for noise as a test to the repair.

Inspect the transducer cord for corrosion or wear. If present replace the transducer cable by unplugging it from the transducer and display screen and then plugging the replacement in the units.

Wipe down the control buttons on the display screen if they are sticky and unresponsive. Use the chamois cloth and sponge with warm water to clean the buttons. Spray them with the compressed air to free sediment from under the keys.


  • For electronic motherboard or other repairs, take the unit to a certified Humminbird repair shop or send the unit to Humminbird for service.
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