20 Most Recent Garmin Fishfinder 400c With Dual Beam Transducer Questions & Answers

mode then push unit then push reset to factory settings

check the battery voltage as low voltage can cause the unit to display errors and prevent the sonar from starting up. This unit is more sensitive to low voltage than many other electronics. If charging the battery or replacing it with a known good battery doesn't work then contact garmin for a replacement of your fishfinder.

Updating Handheld/Portable Devices If your device has removable batteries, such as 2 AA batteries or a lithium-ion battery pack, then it is a handheld/portable device. You can update your device software for free using WebUpdater and a compatible cable.
Updating Fixed Mount Devices If your device needs to be hard-wired to your boat's power supply, then it is a fixed mount device. You can update the software by inserting a data card containing a software update bundle into your device.
You have 2 options for obtaining the update bundle:

1. Do it yourself: Download the free software update bundle to a data card (SD™ card and card reader or Garmin Data Card and Garmin Data Card reader required).
2. Purchase the software update bundle on a preloaded data card.

Get the software and instructions here:

http://www8.garmin.com/support/software/marine.html

I would recommend having the back part of the transducer a little higher (toward the sky) than the nose of the transducer. When I say a little, I mean a very slightly. This way the nose of the transducer pushes the water and any bubbles away from the face.

Is the transducer extending below the waterline?

The rest of the wires are for interfacing (letting the unit 'talk') with other devices such as radar or GPS. These wires/colors are pretty standard and defined by NEMA (National Electrical Manufacturers Association). You need wiring diagrams for the devices to hook them up. For fun, see where 'nema' takes you with Google.

Hi there.

Ok in WIDE beam mode the cone extends out 45 degrees from the transducer. This covers a fair area, but is best used only in shallow waters as the beam may not have enough power to penetrate deeper waters effectively. 30ft should be fine for WIDE mode however. Using a bit of trigonometry, the beam would extend to a diameter of 60 feet from the center point of the transducer on the sea/river floor.

The beam is a direct beam... It is not a rotational beam from the transducer... i.e. it does not rotate like a radar beam but shoots downward in the cone arc constantly. Imagine a torch being turned on and off very rapidly... The light shoots straight out from the torch in its own cone shape. This is essentially what the transducer does when it shoots out a signal every millisecond or so.

The image you see on the screen is the result of the hole cone of signals, however, the strongest sonar returns occur near the center of the beam. Weaker returns are shown which are located towards the outer edges of the sonar cone where the signal power is less. So if a fish passes right on the edge of the beam, it will only show up as maybe 1 pixel on the sounder screen as it is a weak return on the edge of the sonar cone, whereas if that fish passes under the center of the beam, it will show a larger, more continuous or arched shaped return as the fish moves from the outside of the beam, through the center of the beam, and out to the other edge of the beam under the boat.

Regarding the flasher... I would advise not to use this. It does work by showing a continuous top and bottom reading which displays as constant flashes around the circle readout. Anything it picks up in the beam will show as flashes in between the top and bottom readings. Using the display is far better and with practice allows you to better identify fish and bottom structure readings. Flashers were earlier forms of sonar readouts. Some older folk still like them but I believe the normal display is better for finding and identifying fish and can show structure shape as well (the flasher mode really cannot).

Hope that helps!

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All transducers should read 0 ohms or close to it. If not you most likely have a broken pin in the connector or wire.

I can't remember correct setup but make sure that box is powered and connected to GPS in right input. With no power to box it won't be discovered by head unit.

Place your ear against the transducer with unit ON. You should hear it 'tikking' ( tic tic tic ) then the transducer is ok...

garmin_products_out_of_support_list_20140207 Here is a pdf for Garmin. you should be able to contact them though email. Good luck

https://www.garmin.com/en-US