Humminbird Fish Finder 405SX User Manual

405SXSINGLEBEAM  
fishfinder  
OPERATIONS MANUAL  
 
TABLE OF CONTENTS  
Section 1: Installation preparation . . . . . . . . . . . . . . . . . . . 2  
Parts Supplied . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2  
Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2  
Installation Overview . . . . . . . . . . . . . . . . . . . . . . . . . 2  
Alternative Transducers and Mounting Methods. . . . . . 4  
Beginning Installation . . . . . . . . . . . . . . . . . . . . . . . . . 5  
Section 2: USING THE 405SX. . . . . . . . . . . . . . . . . . . . . . . 6  
How Sonar Works . . . . . . . . . . . . . . . . . . . . . . . . . . . 6  
Simulator Operation . . . . . . . . . . . . . . . . . . . . . . . . . . 6  
What You See On Screen . . . . . . . . . . . . . . . . . . . 711  
Control Functions . . . . . . . . . . . . . . . . . . . . . . . . 1115  
Menu Functions . . . . . . . . . . . . . . . . . . . . . . . . . 1525  
Section 3: ADVANCED FEATURES. . . . . . . . . . . . . . . . . . . 24  
Using Diagnostic . . . . . . . . . . . . . . . . . . . . . . . . . . . 24  
Section 5: MAINTENANCE/WARRANTY. . . . . . . . . . . . . . . 25  
Maintenance and Troubleshooting . . . . . . . . . . . . 2628  
Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29  
Service Policy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29  
Customer Service . . . . . . . . . . . . . . . . . . . . . . . . . . . 30  
Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31  
Rev 10416E  
 
INSTALLATION PREPARATION  
PARTS SUPPLIED  
PARTS SUPPLIED  
Before installing your 405SX, please ensure the following parts are included in  
the box:  
405SX fishfinder  
Transducer with 20' of cable and mounting hardware kit  
Mounting system and mounting hardware kit  
6' power cable  
Publications kit  
+
Note: The 405SX includes a temperature sensor and the 405SX  
includes speed and temperature sensors with appropriate  
hardware and instructions for installation.  
If any of these items is missing contact your local dealer.  
ACCESSORIES  
Humminbird offers a wide assortment of accessories that complement and  
expand the capability of your new 405SX. These accessories are designed with  
the same high standards. The Humminbird Accessory catalog included with  
your unit contains descriptions of the many accessories available and ordering  
information. All Humminbird accessories are available through your full-service  
Humminbird dealer.  
INSTALLATION OVERVIEW  
The 405SX consists of two primary components to install: the control head and  
the transducer.  
The control head contains the sonar transmit and receive circuitry, as well as the  
user controls and display. It should be installed in a location that provides access  
to the controls and visibility while in use. The control head mounts on a quick  
disconnect mounting system that swivels and tilts, providing flexibility for  
viewing from almost anywhere on the boat.  
2
 
INSTALLATION PREPARATION  
INSTALLATION OVERVIEW  
The transducer converts electrical energy from the transmitter into mechanical  
pulses or sound waves. The transducer also receives the reflected sound waves  
and converts them back into electrical signals for display on the control head. It  
should be installed in contact with the surface of the water in an area that has  
smooth water flow - usually on the transom of the boat. There are several  
mounting options for the transducer. Review the  
following section to determine the method that  
works for you and your boat.  
Determining How to Mount the  
Transducer  
The 405SX includes a model XT-6-24 transducer.  
This transducer can be mounted on the transom  
of the boat, or bonded to the inside of a  
fiberglass hull boat.  
The transom installation, which is the most  
widely used, places the transducer on the outside  
of the boat hull. This technique produces the  
Transom Mounted Transducer  
least signal loss, and provides a way to adjust the  
transducer after installation. The mounting  
hardware included is designed to  
protect both the boat and the  
transducer should the boat strike  
debris in the water or when trailering.  
As an alternative to transom mounting,  
it is possible on many fiberglass-hulled  
boats to glue the transducer on the  
inside of the boat hull. Since fiberglass  
has similar sonar characteristics as  
water, the sonar signal can pass  
through the boat hull with minimal  
loss. The hull of the boat must be single  
layer construction (not double-hulled).  
Inside the Hull Mounted Transducer  
Also, any air trapped in the lamination  
of the fiberglass would prevent the  
sonar signal from passing through.  
For additional details reference the  
TRANSDUCER INSTALLATION section of  
the enclosed Installation Sheet.  
3
 
INSTALLATION PREPARATION  
ALTERNATE TRANSDUCERS AND MOUNTING METHODS  
Inside the hull installations require no holes to be drilled into the boat and  
through experimentation, high-speed operation comparable to transom  
mounting can be achieved. Two part, slow cure epoxy is required to glue the  
transducer in place.  
ALTERNATE TRANSDUCERS AND MOUNTING METHODS  
The 405SX comes with everything necessary for installation and operation on  
most boats. However, there are several situations which may require a different  
type of transducer. Inboard boats, wood or metal hulls, and sail boats create  
unique transducer mounting needs. Alternate transducers and mounting  
methods are detailed below.  
Portable Mounting  
The standard transducer can be adapted for  
portable installations using part number MHX-PT2.  
This accessory adapts your transducer to a suction  
cup mount for temporary installation on the boat  
hull or other surface.  
Trolling Motor Mounting  
The standard transducer can also be adapted to  
mount on most trolling motors using part number  
AD-STM-7. This accessory includes a bracket and  
hose clamp that allows mounting the transducer to  
the body of most trolling motors.  
TRANSDUCER EXCHANGE  
Other transducers are available as replacements for  
the standard transducer. You may exchange your  
new and unassembled transducer for another type  
by returning it to the address listed in Customer  
Support. Some transducers may have additional costs. Refer to the Accessory  
catalog or call Customer Support for information.  
4
 
INSTALLATION PREPARATION  
BEGINNING INSTALLATION  
BEGINNING INSTALLATION  
Now that you have determined the transducer mounting method, you can  
begin installation of the 405SX. The fold out installation guide included  
provides detailed step by step instructions for installation of the control head  
and transducer. For transom mount transducer installations, you will need the  
mounting template at the back of this manual.  
In addition to the parts included you need the following for installation and  
operation:  
A powered hand drill and various drill bits  
Phillips and flat-head screw drivers  
A ruler or measuring tape  
Pen or pencil  
12 volt power source (your boats battery)  
A 1-amp fuse  
A fuse holder (if you are wiring directly to the boats battery)  
Silicone sealant (for sealing drilled holes)  
2-part, slow-cure epoxy (for inside the hull transducer installations)  
+
Note: If you have purchased the 405SX you will have in addition  
to the parts and instructions above:  
Speed and Temperature sensors  
Instructions for installing speed and temperature sensors  
Appropriate hardware to mount sensors  
5
 
USING THE 405SX  
HOW SONAR WORKS  
HOW SONAR WORKS  
Your Humminbird unit uses sonar to  
locate and define underwater objects,  
define the bottom terrain, as well as  
determine distance.  
Sonar technology is based on sound  
waves. Your Humminbird unit sends out  
a sound wave signal. With this signal it  
determines distance by measuring the  
time between the transmission of the  
sound wave and when the sound wave  
is reflected off an object. Your  
Humminbird uses the reflected signal to  
interpret location, size and composition  
of an object.  
Sonar is very fast. A sound wave can travel from the surface to a depth of 600'  
and back again in less than ¹⁄₄ of a second. It is unlikely that your boat can  
"outrun" this sonar signal.  
The 405SX is a 200 kHz, single-beam fishfinder. The 200 kHz frequency  
provides excellent sonar resolution (the ability to distinguish small returns or  
returns which are close to the bottom), while providing depth capabilities to  
600. The shape of the sonar beam is symmetrical and covers an area of  
approximately 24 degrees side to side and front to rear.  
Actual depth capability depends on factors such as bottom hardness, water  
conditions, and transducer installation. Units will typically read to deeper  
depths in fresh water than in salt water.  
SIMULATOR OPERATION  
The 405SX contains a simulator that allows you to use the unit as if you are on the  
water. The simulator is invaluable for learning how to operate the 405SX.  
There are two ways to start the simulator. If the unit is powered off, press and hold  
the POWER button for approximately three seconds until you hear a continuous chirp.  
The simulator can also be started by selecting the Simulator option on the start-  
up screen after you power-up the unit. When this screen is shown, simply press  
6
 
USING THE 405SX  
SIMULATOR OPERATION  
the DOWN ARROW until Simulatoris  
highlighted. When the screen times out, the  
unit will be in simulator mode.  
When in simulator operation, the 405SX  
responds to control inputs as if it is in actual  
operation, so feel free to experiment, or to  
customize the unit for your particular  
operation.  
To exit Simulator mode, power the unit off.  
FEATURE MEMORY  
If your 405SX is installed with a transducer connected, any changes you make  
to the set-up or User Options (see Control Functions) while in Simulator are  
retained in the units memory. This allows you to use simulator to experiment  
with the various set-up options, and retain your selected settings for normal  
operation.  
If you are using the 405SX in Simulator when no transducer is connected, any  
selected options are lost when the unit is powered off. The 405SX will return  
to Factory Settings, or options selected when last used with a transducer, if no  
transducer is connected.  
IMPORTANT: A transducer must be connected to the 405SX in  
order to retain user settings selected when in simulator mode. If  
no transducer is detected, the unit defaults to pre-selected  
options when powered off.  
What You See On-Screen  
Your 405SX uses a 160 x 160 matrix FSTN LCD display. This display provides  
outstanding viewability in all light conditions over a wide range of  
temperatures.  
At initial power-up, the 405SX uses settings that were set at the factory. After  
initial use, the 405SX will remember the settings you enter.  
There are several elements on-screen that are common to all modes of operation.  
7
 
USING THE 405SX  
WHAT YOU SEE ON-SCREEN  
Temperature/Speed. The initial screen layout takes one of two basic forms  
depending on whether the optional Temp/Speed accessory is installed. Figure  
A shows the default view when the Temp/Speed accessory is installed. Figure B  
shows the default view when the Temp/Speed accessory is not installed.  
Depth. The digital depth  
Figure A  
number shows the water depth  
directly beneath the transducer  
location.  
Depth Range. The depth range  
is shown to the right of the screen.  
The upper number is 0 indicating  
the surface of the water. The lower  
number is one of the nine depth  
ranges available that best match the  
depth of the water. As the depth of  
the water changes, the range  
changes as necessary in order to  
retain a bottom representation on-  
Figure B  
screen. When in Auto mode,  
the horizontal line at the top  
of the screen is the zero  
line,representing the surface  
of the water. Occasionally  
there is a gap in this line. This  
gap indicates the unit is up-  
dating the display even if the  
bottom is not visible on-  
screen, or if the bottom  
information is not changing.  
Bottom Depiction  
Zero Line  
New sonar information appears  
on the right side of the graphic  
area of the display and moves  
to the left as new information  
is displayed. The 405SX  
Water Depth  
Depth Range  
automatically  
selects  
the  
appropriate depth range to show the depth of water beneath the transducer.  
8
 
USING THE 405SX  
WHAT YOU SEE ON-SCREEN  
This range is selected so the bottom representation is typically shown about ²⁄₃  
down the display.  
Bottom. The graphic depiction of the bottom provides the user with an  
effective tool for understanding the composition of the bottom. The FSTN type  
display uses 4 discrete levels of gray to indicate the intensity of the returned  
sonar signal. The 405SX can display even the smallest sonar returns with light  
gray pixels. Larger returns are displayed with darker shades of gray. If the  
bottom is hard and smooth, the bottom depiction is narrow and dense. If the  
bottom is soft mud or sand, the depiction will be thick and less dense. This  
indicates that much of the signal is absorbed by the soft bottom. If the bottom  
is rocky or rugged in composition, the depiction is of varying density and  
textured in appearance.  
Wave action also affects the bottom depiction. The information drawn is a  
distance measurement, so if the boat is moving up and down over flat bottom,  
the bottom depiction often appears in regular variations that match wave  
timing.  
Structure. Structure is defined as any object physically attached to the bottom.  
The sonar configuration of the 405SX is optimized to give the most accurate  
depiction of bottom structure possible. Grass, trees, stumps, wrecks or other  
debris are accurately displayed, however the depiction of these objects varies  
with boat speed and direction. The  
best way to learn to interpret  
Surface Clutter  
Rocky Bottom  
structure is to operate the 405SX  
over a variety of known conditions  
and experiment with user functions  
to best represent those conditions  
on-screen.  
Surface Clutter. Surface clutter is  
the layer of water near the surface  
that is rich in algae and other  
growth, and often is aerated by  
wind or wave action. This area of  
water interferes with sonar  
transmission and often appears on-  
screen as regular clusters of ind-  
ividual dots near the 0line.  
Hard Bottom Soft Bottom  
9
 
USING THE 405SX  
WHAT YOU SEE ON SCREEN  
Thermoclines. Thermoclines are  
sharp differences in water  
temperature. These are easily  
identified by the continuous  
nature of the return.  
Thermocline Second Return  
Second Returns. When a sonar  
signal is reflected off the bottom  
back to the transducer, there is  
often enough energy left in the  
signal to be reflected off the  
surface of the water back to the  
bottom a second time. Second  
returns appear as a slightly  
weaker bottom representation  
exactly twice the depth of the primary bottom return. The second return is most  
likely to occur in shallow water and in areas of relatively hard bottom.  
Fish Arches. With Fish ID off, schools of bait  
fish as well as individual fish are clearly visible  
on the 405SX display. Bait fish appear as  
"clouds" having different shapes and sizes  
depending on the number of fish and boat  
speed. Individual fish appear as smaller black  
Fish Arch Diagram  
and gray lines often appearing as a "fish arch."  
A fish arch forms as the boat move over the fish. Due to the transducer  
beam angle the distance to the fish decreases as it moves into the beam,  
and then increases as it moves out. When the window graphs this distance  
change, an arch appears. The true depth of the fish is the top of the arch  
when the boat is directly over the fish. Boat speed and movement of the  
fish greatly affect the shape of the arch. When moving slowly, a fish creates  
an elongated arch. With the boat moving fast the arch appears shorter. A  
partial arch forms when the fish does not move through the entire cone angle.  
The 405SX displays structure such as submerged grass, brush, trees and  
wrecks on the bottom. Structure can be distinguished by comparing the  
area just above and below the main bottom return. Usually structure shows  
as areas of dark to light gray on top of a dark bottom contour. The  
appearance of structure is greatly affected by boat speed and direction; to  
10  
 
USING THE 405SX  
WHAT YOU SEE ON SCREEN  
repeat the same image it is often necessary to travel the same speed and  
direction over the location where the structure was originally located.  
The 405SX is also capable of showing layers of water having different  
temperatures. These temperature differences, called thermoclines, appear at  
different depths, depending on current conditions. A thermocline typically  
appears as a continuous band of light gray moving across the display at the  
same depth. Thermoclines always appear above the bottom.  
It is important to remember that sonar cannot distinguish between a fish  
and some other object suspended in the water. Regardless of the object the  
sonar detects, each will be drawn as an arch.  
Fish ID. The 405SX uses  
advanced signal processing  
to further evaluate any  
sonar return between the  
surface and the bottom. For  
instance, a small school of  
bait fish usually appears as a  
dense cluster of individual  
dots. If the return meets  
certain additional criteria, a  
fish symbol will be assigned.  
There are three different  
size fish symbols used to  
indicate the intensity of the  
sonar return. While signal  
ID+ Fish Depth  
intensity is a good indicator of relative fish size, different species of fish have  
different sonar characteristics, so it is not always possible to distinguish fish size  
between varying species. The signal intensity is "normalized" for depth so that  
a small fish close to the boat does not appear as a large fish symbol.  
ID+ adds an additional piece of information to help the user locate fish. On selected  
fish symbols, the digital depth of the designated fish is drawn to help locate the fish  
vertically. This is especially helpful in setting bait depths or for downrigger  
operation.  
11  
 
USING THE 405SX  
CONTROL FUNCTIONS  
CONTROL FUNCTIONS  
The 405SX uses a simple six button keypad for all user input. Press any button  
and an audible chirpconfirms the control input. If a button has no function or  
is inappropriate for the situation, an audible erroris heard. The unit sounds  
multiple chirps.  
Power. The Power button powers the 405SX up for normal operation. When the  
unit is on, POWER turns the unit off. POWER can also be used to go directly into  
Simulator mode. To enter simulator, with the unit powered off, press and hold  
POWER for several seconds until a continuous chirp is heard.  
Light. LIGHT controls the units display backlight. With the unit powered on,  
press LIGHT once to turn the backlight on low.Press LIGHT a second time to  
turn the backlight on medium,a third time to turn the backlight on high,  
and a fourth time to turn the backlight off. The backlight is very effective for low-  
light and nighttime operation. When the backlight is on, the 405SX will consume  
more power than with the backlight off. This is important when using the 405SX  
in a portable configuration powered by a separate battery, or when powering the  
unit from a trolling motor battery.  
When powering the unit from a battery such as in portable  
applications, you can prolong the battery life by using the  
backlight at a minimum.  
The three lower buttons, MENU, UP ARROW and DOWN ARROW work together  
to control the 405SX menu-controlled user functions.  
View. VIEW selects one of several screen configurations or  
viewspossible depending on the transducer in use. When using  
the standard transducer, without the optional speed/temp sensor  
connected, the VIEW button toggles the display between the full-  
screen 2D View and the Large Digital Readout View.  
The 2D View is the default view, and the view which is first seen  
at power-up. Pressing VIEW again will select the Large Digital  
Readout View, which increases the size of key digital information  
so that it can be viewed from a great distance. Normal 2D  
information is displayed on the right side of the display. Pressing  
VIEW again will toggle the display back to the 2D view.  
12  
 
USING THE 405SX  
CONTROL FUNCTIONS  
2D View  
When using the standard  
transducer, with the optional  
speed/temp sensor connected,  
the VIEW button toggles the  
display between the full-screen  
2D View, the Chart View and  
the Large Digital Readout View.  
The Chart View, shows only the  
digital depth readout, leaving  
more screen area for fish  
location and bottom depiction.  
Menu. MENU displays a menu  
on-screen for adjustment. In  
normal operation, pressing  
Large Digit View  
MENU  
repeatedly  
cycles  
through all available menus. A  
menu remains on-screen for  
several seconds, and can be  
adjusted by using the ARROW  
keys. If no adjustment is made  
in the allotted time, the menu  
disappears. If you want the  
menu to remain on-screen  
longer press and hold MENU—  
the menu will remain on-screen  
indefinitely. Once you release  
the menu button, the screen  
will time out. Once a menu  
times out, it is still considered  
the active menu. Press MENU  
to bring up the last menu used.  
Chart View  
Arrow Keys. The UP ARROW  
and DOWN ARROW make  
adjustments to menu functions.  
On the left side of every menu  
there are UP ARROW and  
13  
 
USING THE 405SX  
MENU FUNCTIONS  
DOWN ARROW symbols. The symbols indicate which ARROW button has a  
function in a particular situation. Either one or  
Menu  
both ARROW buttons can be used to adjust the  
menu function. A hollow ARROW symbol means  
the corresponding ARROW button has no  
function. Pressing that button will result in no  
adjustment and the erroraudible will be  
heard. A solid ARROW symbol means the  
corresponding ARROW button can be used to  
affect the menu adjustment.  
Abbreviated Menu. The ARROW buttons often can be  
used when no menu is on-screen. In these situations,  
pressing the ARROW button affects the function of the  
active (last-used) menu. This is a short-cut to menu  
Abbreviated Menu  
operation. An abbreviated menu appears on-screen while  
the adjustment is made and times out. A frequently used menu can be  
adjusted very quickly using this technique.  
After an adjustment is made to a menu function, the menu times out after a few  
seconds and the unit returns to normal operation.  
Heading  
Up Arrow Option  
Arrow Symbols  
Selected Setting  
Down Arrow Option  
Range of Adjustment Indicator  
Menu Layout. All menus use the same basic layout. The heading at the top  
describes the menu function. The UP ARROW and DOWN ARROW symbols to  
the left of the menu indicate which buttons are available for adjustment. In  
menus that have several possible settings, a range of adjustment indicator shows  
the total range available and the current setting.  
Within the menu are the options available. The selected option or current  
setting is highlighted in the black box. If no adjustment is made, this is the  
selected setting. Press an ARROW button while the menu is displayed to select  
another option.  
14  
 
USING THE 405SX  
MENU FUNCTIONS  
Several of the menus are multi-step. In some situations if an adjustment is  
made, additional options become available for further adjustment. Examples of  
these multi-step menus are Depth Range, Depth Alarm and Zoom. See the  
detailed description of each function for further explanation.  
Menu Functions  
Sensitivity. The Sensitivity function controls the  
sensitivity of the sonar receiver. The 405SX  
automatically adjusts the level of receiver  
sensitivity based on a number of factors including  
the depth of the water and the level of noise  
present. Noise can be caused by other electronic  
devices, engines, trolling motors, propeller cavitation and hydrodynamic flow  
among others. The user has the option of adjusting the Sensitivity higher or  
lower based on personal preference. You can select one of 11 sensitivity  
settings from -5 to +5. A setting of 0 (factory setting) has no effect on the auto-  
matic  
sensitivity  
control.  
Increasing  
the  
sensitivity  
(+1 through +5) enables the unit to display the information from progressively  
smaller sonar returns. By decreasing the sensitivity (-1 through -5), the unit  
effectively filters small sonar  
returns.  
High Sensitivity (+) Sensitivity at “0”  
In murky or muddy water, it is  
often helpful to reduce the  
sensitivity. This prevents the  
display from being cluttered  
with sonar returns from debris  
or suspended particles. In very  
clear or very deep water, it may  
be helpful to increase the  
sensitivity since even the  
smallest sonar return may be of  
interest to the user.  
Low Sensitivity (-)  
To adjust Sensitivity, press MENU repeatedly until the Sensitivity heading is  
displayed. When the Sensitivity menu appears, use the UP ARROW to increase the  
sensitivity, or the DOWN ARROW to reduce sensitivity. To sequence through the  
available settings, press and hold either ARROW button. Release the button at the  
setting you want to select.  
15  
 
USING THE 405SX  
MENU FUNCTIONS  
After an adjustment is made, the menu  
disappears and the new sensitivity setting is in  
affect. If additional time is needed to study a  
menu, press and hold the MENU button and  
the menu will remain on-screen indefinitely. If  
you need to make an additional adjustment,  
press the UP ARROW or DOWN ARROW  
button.  
Depth Range. The Depth Range function  
controls the vertical distance displayed on the  
graphic area of the display. There are nine  
depth ranges available. The top of the range is  
always 0, or the surface of the water. Ranges  
of 015', 030', 060', 0120', 0180',  
0240', 0360', 0480', and 0600'. The range  
that positions the bottom depiction closest to  
the bottom of the screen, will best utilize the  
available display resolution.  
Using the factory setting of AUTO the 405SX  
can automatically adjust the depth range  
depending on the depth of the water. The unit  
tries to maintain the bottom depiction about ²⁄₃  
down the total range (for example, in 20' of  
water, the 0-30' range would be  
selected). This provides the best  
display resolution and therefore  
the best target separation  
possible.  
The Depth Range can be  
adjusted manually. Press MENU  
repeatedly until the Depth  
Range menu is visible. Two  
options are available: Auto and  
Manual.  
The manual setting enables you  
to adjust the current depth  
Depth Range  
16  
 
USING THE 405SX  
MENU FUNCTIONS  
range setting. The unit no longer adjusts the Depth Range to the most appropriate  
range for bottom display. Often, the bottom may not be visible on-screen. The  
digital depth readout always determines the depth of the bottom, even if it is not  
visible on-screen.  
Using manual Depth Range control, you can view sonar information from the area  
near the surface in greater detail.  
To return to automatic Depth Range control, press the MENU button until the  
Depth Range menu appears on-screen and use the UP ARROW to select AUTO.  
Zoom. The 405SX uses a greatly enhanced Zoom  
capability called TruZoomwhich offers  
expanded information on a select area of sonar  
information. Zoom is similar to Depth Range  
because it controls the range of information  
displayed on screen. Zoom, however, allows for  
selection of ranges beneath the surface so any  
area of water between the surface and the bottom can be enlarged to provide  
more detailed information. By using the full display to show a small area of  
coverage, the effective display resolution is increased, and the units ability to  
separate close targets is enhanced.  
The Zoom ranges available are dependent on the  
current depth range. In the 15' depth range,  
TruZoom displays a range equal to one half the  
current depth range. In the 30', 60', 120', 180',  
240', 360', 480' and 600' depth ranges,  
TruZoom displays a range equal to one fourth the  
current depth range. The box at the right side of  
the screen outlines the area to be zoomed.  
The 405SX shows Zoom range in conjunction  
with the full depth range. The Zoom range is shown on the left side of the  
screen and full range information is shown on the right side of the display. The  
area which is being enlarged by Zoom is indicated by the square box. Zoom can  
either operate automatically, in which the Zoom range is constantly adjusted to  
show the bottom, or manually, in which the user controls the location of the  
Zoom range.  
17  
 
USING THE 405SX  
MENU FUNCTIONS  
AutomaticZoom is especially helpful when looking  
for structure or bottom detail. The AutomaticZoom  
keeps the bottom in view even in quickly changing  
terrain. ManualZoom provides detailed information  
of any area from the surface to the bottom.  
In ManualZoom, the Zoom range does not move as  
the terrain changes. To operate Zoom, press MENU  
repeatedly until the Zoom menu is on-screen. Three  
options are available: Off(Factory Setting), Auto”  
(Automatic bottom tracking Zoom), and Manual(User  
controlled Zoom range). Press the DOWN ARROW once  
to highlight Auto or twice to highlight Manual. If  
Manual is selected a submenu will appear allowing  
manual zoom range adjustment. When the menu  
disappears, full range information is displayed on the  
right as always. The square box indicates the Zoom  
range. In Auto Zoom, the box will move vertically to  
remain in the general area of  
the bottom return. The left  
Upper Zoom Limit  
side of the screen is  
a
magnified view of the  
information seen inside the  
Zoom range box. The upper  
and lower depth limits of the  
Zoom range are shown on the  
right side of the Zoom view.  
Note: It is not possible to  
use Zoom in conjunction  
with the Large Digital  
View.  
Lower Zoom Limit  
To disable Zoom, press the MENU button until the Zoom menu is on-screen. Use  
the UP ARROW to highlight Off, and let the menu time out.  
When the unit is powered off, the Zoom menu returns to Zoom Off.  
18  
 
USING THE 405SX  
MENU FUNCTIONS  
Depth Alarm. The 405SX contains an audible  
alarm to warn you of shallow water depths. The  
alarm is adjustable to depths of 2' to 99'. When  
the alarm is enabled, an audible alarm sounds if  
the water beneath the boat is equal to or less than  
the selected alarm depth. The alarm sounds  
continuously for about five seconds, and then  
intermittently to remind you that you are still in  
shallow water. Additionally, the 405SX can  
anticipate quickly changing terrain and sound  
the Depth Alarm before the bottom depth  
actually reaches the preset alarm depth.  
Fish Alarm. The Fish Alarm alerts you to the  
presence of fish, or other targets not connected  
to the bottom. The Fish Alarm has three different  
settings that correspond to the three different  
size fish symbols shown on-screen.  
The default setting is OFF.With the Large  
fish onlysetting, the 405SX alarms on only  
those targets that are represented by the large  
fish symbols. The 405SX can be set to alarm on  
only large and medium fish, or set to alarm on  
all fish.  
Once the Fish Alarm is enabled, the 405SX emits  
an audible beep when the selected size fish  
symbol appears on-screen.  
Fish Alarm settings are remembered when the  
unit is powered off.  
19  
 
USING THE 405SX  
MENU FUNCTIONS  
Triplog. Triplog provides a running log of  
information based on input from the Temp/Speed  
sensor.  
Since Triplog requires information from  
the Temp/Speed sensor to operate, if this  
sensor is not detected by the 405SX, the  
Triplog menu will not appear as an  
option.  
Triplog  
Triplog provides four pieces of  
information: the total time  
elapsed since power-up or  
reset, the distance traveled  
since the 405SX was powered  
up or reset, the average speed,  
and the input voltage from  
your boats electrical system.  
The time, speed and distance  
calculations are useful for  
tracking your progress on a  
trip. The input voltage is useful for determining the condition of the charging  
system of the boat. When used in a portable application or whenever the  
405SX is operated from a battery source, the voltage number can be used to  
determine battery life. The 405SX will operate at voltages from 10 to 20 VDC.  
Voltages in excess of 20 or less than 10 VDC cause the unit to power off. The  
Triplog resets at power off.  
Options. The Options Menu is a series of linked menu functions used initially  
to set your preferences. Once your preferences are selected, it is unlikely these  
functions need to be accessed during the normal operation of the product.  
There are eight Option menus: Contrast, Units, Fish ID, Numeral size,  
Transducer, Display Speed, Bottom Black and Reset. Press the view key at any  
time to exit options and return to normal operation.  
20  
 
USING THE 405SX  
MENU FUNCTIONS  
Contrast. The Contrast function allows the user to  
control the level of contrast of the LCD display. The  
405SX will automatically adjust the display contrast  
to compensate for changing ambient temperatures;  
however, some situations may occur where manual  
adjustment will provide a higher level of contrast.  
Eleven contrast settings, +5 to -5, are possible. The  
display contrast will change as the adjustment is  
made so the optimum level of contrast can easily be  
adjusted. Use the ARROW buttons to highlight the  
desired selection.  
Display Speed. Display Speed controls the rate at  
which the graphic information moves across the  
display. There are 5 possible speeds; the fastest rate  
(5) is the factory setting. If your boat is stationary  
or moving very slowly for extended periods, it  
may be desirable to update the display at a  
slower rate. The closer the update rate matches  
boat speed, the more accurate is the graphic  
depiction of the terrain beneath your boat.  
Use the UP and DOWN ARROWS to select the  
desired update rate. (1) is the slowest, (5) is the  
fastest. Use the MENU button to advance to the  
next menu.  
The Display Speed setting is remembered when the unit is powered off.  
Battery Alarm. The Battery Alarm Option allows  
you to select the voltage level at which the Battery  
Alarm activates. At the Battery Alarm menu (under  
options), you will note that the default setting is  
OFF. Push the DOWN ARROW BUTTON to select  
the feature ON. Push the DOWN ARROW BUTTON  
again to move into the ADJUST BATTERY ALARM  
setting. Using the UP and DOWN ARROW  
BUTTONS, select a voltage between 9.0 and 12.0. When the voltage drops  
below your selected voltage, an audible alarm will sound, and a battery alarm  
icon will be displayed on screen with current voltage level.  
21  
 
USING THE 405SX  
MENU FUNCTIONS  
Bottom Black. There are two selections  
available: Off and On. The factory setting is  
Off. With this setting, the 405SX displays  
the bottom using 4 level grayscale. This  
allows you to determine the texture and  
relative hardness of the bottom. Selecting  
Bottom Black ONcauses the unit to  
blacken in the display below  
the bottom. This gives the  
user easiest recognition of the  
bottom location, even from a  
great distance.  
The 405SX remembers the  
Bottom Black setting when  
powered off.  
Fish ID. There are three  
selections available: Off, ID+  
ON, and Adjust. The factory  
setting is ID+ OFF. With Fish ID  
Off, sonar returns are  
Bottom Black View  
displayed as rawinformation. There is no interpretation made by the unit.  
Selecting ID ON also enables the fish alarm.  
ID+ On enables the to interpret the raw sonar data and,  
using a variety of techniques, depict appropriate target  
returns as one of three different size fish symbols. Further  
identification shows which beam the fish is detected in.  
The 405SX also displays the depth beneath the surface  
with the corresponding fish symbol.  
ID+ On Raw Sonar  
Selecting Adjust and making incremental changes  
enhances the fishfinders ability to identify sonar  
returns as fish symbols.  
Increasing the value to a number greater than zero  
shows more fish symbols on-screen. In this case  
smaller sonar returns will be depicted as fish  
symbols. This is useful for identifying many smaller  
sonar returns (such as bait fish) as fish symbols.  
22  
 
USING THE 405SX  
MENU FUNCTIONS  
Decreasing the value to a number less than zero shows  
fewer fish symbols on-screen. In this case smaller sonar  
returns are disregarded. This is useful for eliminating many  
small sonar returns when seeking larger species of fish.  
The 405SX remembers this selection even when the  
unit is powered off.  
Numeral Size. Two options are available: Big and  
Small. The factory setting is Big. With this setting, the  
digital depth and speed and temp numerals are drawn  
large enough to be read from across the boat. The big  
numerals occupy space on the display that could be  
used for the graphics area. Hence, the small numerals  
option. With small numerals selected, a greater amount  
of the display area is available for the graphic view. This  
effectively increases the display resolution of the unit.  
Numeral Size settings are remembered when powered off.  
Units Speed. Units of Speed allows the selection of  
MPH (statute miles per hour), or KTS (nautical miles per  
hour). Use the Arrow buttons to highlight the desired  
selection.  
Speed Offset. The Speed Offset option allows the user  
to compensate for differences in hull design, and its  
effect on the accuracy of the speed measurement. If  
there is a discrepancy between the indicated speed and  
another speed measurement device on the boat, the  
speed measurement can be varied to improve accuracy.  
Remember, the speed paddle wheel measures speed  
through the water, not speed over ground.  
Speed offset is remembered after power is disconnected.  
Depth Offset. The Depth Offset allows the user to select  
the point on the boat from which the depth measurement  
is made. Selecting a positive value adds distance to the  
measurement. If the transducer is mounted 1 metre  
beneath the waterline, a positive 1 will show the correct  
depth from the surface of the water.  
23  
 
USING THE 405SX  
USING DIAGNOSTIC  
Another frequent use of depth offset is to show the depth beneath the deepest point  
of the hull. A negative value equal to the distance from the transducer location and  
the deepest point of the hull will have the same effect as mounting the transducer at  
the deepest point.  
Depth offset is remembered after power is disconnected.  
Reset. With the many User Options available to  
customize the 405SX, it is easy to configure the unit  
in such a way that it is detrimental to a particular use.  
By using the Reset function, all variable or user-  
controlled features of the 405SX are returned to the  
factory settings.  
The Reset function is an important first step in  
troubleshooting problems to ensure that a user selected setting is not the cause for  
the perceived problem.  
USING THE DIAGNOSTIC FEATURE  
The 405SX contains a powerful diagnostic  
tool that can aid in determining the cause  
of a problem.  
To use the Diagnostic feature, select the  
Diagnostic feature on the start-up menu of  
the initial screen.  
Self Test. Initially, the 405SX will  
perform a self-test. This test confirms  
the operation of all internal circuitry.  
At the conclusion of the test, one of two messages will appear. PASSED  
indicates the internal test discovered no failures, FAILED indicates a  
significant internal problem was discovered and the unit requires factory  
service. A code number appears that tells repair personnel where the  
problem is.  
Transducer Connection. The first connection tested is Transducer input. If a  
transducer is detected, the message CONNECTED appears. If a series of dashed  
lines is shown, no transducer is connected or there is a problem with the  
transducer or cable.  
24  
 
MAINTENANCE  
If you are using multiple transducers, switch between transducers to confirm  
the connections for each.  
Voltage Input. Another connection tested is the voltage input, and is  
especially helpful in diagnosing input voltage problems. The current input  
voltage is displayed. If voltage fluctuations or power supply in excess of 20  
VDC or less than 10 VDC is suspected, use the diagnostic screen to confirm  
input voltage. Often, small outboard motors do not effectively regulate  
voltage when operated at high engine speeds.  
Use Diagnostic while running the boat at high speeds to show the voltage  
gain. Also, if you are using the 405SX in portable configuration or from the  
trolling motor battery, Diagnostic can be used to evaluate the health of the  
battery by showing the present voltage.  
Total Time. The total time category indicates the total time the unit has  
been in use since shipped from the factory. It is normal for some hours to  
appear in the total time when the unit is new due to factory testing. While  
this is often of interest to the user, it is primarily a diagnostic tool for the  
repair technician should the unit need service.  
MAINTENANCE  
Your 405SX is designed to provide years of trouble free operation with virtually no  
maintenance. Follow these simple procedures to ensure your 405SX continues to  
deliver top performance.  
If the unit comes into contact with salt spray, simply wipe the affected  
surfaces with a cloth dampened in fresh water. Do not use a chemical glass  
cleaner on the lens. Chemicals in the solution may cause cracking in the lens  
of the unit.  
When cleaning the LCD protective lens, use a chamois and non-abrasive,  
mild cleaner. Do not wipe while dirt or grease is on the lens. Be careful to  
avoid scratching the lens.  
If your boat remains in the water for long periods of time, algae and other  
marine growth can reduce the effectiveness of the transducer. Periodically  
clean the face of the transducer with liquid detergent. Pivoting the  
transducer up in the bracket may allow better access for inspection or  
cleaning.  
25  
 
MAINTENANCE  
MAINTENANCE/TROUBLESHOOTING  
If your boat remains out of the water for a long period of time, it may take  
some time to wet the transducer when returned to the water. Small air  
bubbles can cling to the surface of the transducer and interfere with proper  
operation. These bubbles dissipate with time, or you can wipe the face of the  
transducer with your fingers after the transducer is in the water.  
Never leave the 405SX in a closed car or trunkthe extremely high  
temperatures generated in hot weather can damage the electronics.  
TROUBLESHOOTING  
Do not attempt to repair the 405SX yourself. There are no user serviceable parts  
inside, and special tools and techniques are required for reassembly to ensure the  
waterproof integrity of the housing. Repairs should be performed only by  
authorized Humminbird technicians.  
Many requests for repair received by Humminbird involve units that do not  
actually need repair. These units are returned no problem found.If you have a  
problem with your 405SX, use the following troubleshooting guide before calling  
your dealer or sending your unit in for repair. The 405SX contains several tools  
that can aid in determining if there is a problem and how to isolate and repair the  
problem in many cases.  
1. Nothing happens when I turn the unit on.  
Check the power cable connection at both ends. Be sure the cable is connected  
correctly to a reliable power sourcered lead to positive, black lead to negative  
or ground. Ensure the power available at the mount is between 10 and 20 VDC.  
If the unit is wired through a fuse panel, ensure the panel is powered. Often  
accessory fuse panels are controlled by a separate switch or the ignition switch.  
Also, often a fuse can appear to be good when in fact is not. Check the fuse with  
a tester or replace it with a fuse known to be good.  
Check the power connection to the 405SX. It is possible to force the power cable  
connector into the cable holder incorrectly. If the connector is reversed, the unit  
will not work. Examine the contacts on the back of the unit to ensure there is no  
corrosion. Finally, ensure the unit is firmly seated on the mount. The electrical con-  
tacts are not made until the unit is fully seated.  
Ensure the metal cable retainer is properly installed in the mount. If not, the power  
connection may push out when the unit is put on the mount.  
26  
 
MAINTENANCE  
MAINTENANCE/TROUBLESHOOTING  
2. There is no transducer detected.  
The 405SX has the ability to detect and identify that a transducer is connected.  
First, ensure that an appropriate transducer connector is positioned correctly in  
the connector holder, and that the unit is fully seated on the mount.  
Second, inspect the transducer cable from end to end for breaks, kinks, or cuts in  
the outer casing of the cable. Also ensure the transducer is fully submerged in  
water. If the transducer is connected to the unit through a switch, temporarily  
connect it directly to the unit and try again. If none of these items identifies an  
obvious problem, the transducer itself is probably the problem. Be sure to include  
the transducer if returning the unit for repair.  
3. There is no bottom reading visible on the display.  
There are a number of possible causes for this condition. If the loss of bottom  
information occurs only at high boat speeds, the transducer needs adjusting. If the  
digital depth readout is working but there is no bottom visible on-screen, it is possible  
the depth range has been adjusted manually to a range lower than what is needed  
to display the bottom. Also, in very deep water, it may be necessary to manually  
increase the sensitivity setting to maintain a graphic depiction of the bottom.  
If you are using a transducer switch to connect two transducers to the 405SX,  
ensure the switch is in the correct position to connect a transducer that is in water.  
(If a trolling motor transducer is selected and the trolling motor is out of water, no  
sonar information appears.)  
If none of the above solve the problem, inspect the transducer cable from end to  
end for breaks, kinks, or cuts in the outer casing of the cable. If the transducer is  
connected to the unit through a switch, temporarily connect it directly to the unit  
and try again. If none of these items identifies an obvious problem, the transducer  
itself may be the problem. Be sure to include the transducer if returning the unit  
for repair.  
4. When in very shallow water, I get gaps in the bottom reading  
and inconsistent digital depth indication.  
The 405SX will work reliably in water 2' or deeper. The depth is measured from  
the transducer, not necessarily from the surface.  
27  
 
MAINTENANCE  
TROUBLESHOOTING  
5. The unit comes on before I press POWER, and won’t turn off.  
Check the transducer cableif the outer jacket of the cable has been cut and the  
cable is in contact with bare metal, you need to repair the cut with electrical tape.  
If there is no problem with the cable, disconnect the transducer from the unit and  
see if the problem is corrected, to confirm the source of the problem.  
6. I get gaps in the reading at high speeds.  
Your transducer needs adjusting. If the transducer is transom-mounted, there are  
two adjustments available to youheight, and running angle. Make small  
adjustments and run the boat at high speeds to determine the effect. It may take  
several tries to optimize high speed operation. This can also be a result of air or  
turbulence in the transducer location caused by rivets, ribs, etc.  
7. My unit loses power at high speeds.  
Your 405SX has over-voltage protection that turns the unit off when input voltage  
exceeds 20 VDC. Some outboard motors do not effectively regulate the power  
output of the engines alternator and can produce voltage in excess of 20 volts  
when running at high RPMs. The 405SX displays input voltage in the Diagnostic  
screen. Use this readout to determine if the voltage exceeds 20 VDC.  
8. The screen begins to fade out. Images are not as sharp as normal.  
Check the input voltage using Diagnostic. The 405SX will not operate on input  
voltages below 10 VDC.  
9. The display shows many black dots at high speeds and high  
sensitivity settings.  
You are seeing noise or interference caused by one of several sources. Noise can  
be caused by other electronic devices. Turn off any nearby electronics and see if  
the problem goes away. Noise can also be caused by the engine. If engine noise  
is causing the interference, the problem will intensify at higher RPMs. Increase the  
engine speed with the boat stationary to isolate this cause. Propeller cavitation  
can appear as noise on-screen. If the transducer is mounted too close to the  
propeller, the turbulence generated can interfere with the sonar signal. Ensure  
that the transducer is mounted at least 38cm (15") from the prop.  
28  
 
MAINTENANCE/WARRANTY  
WARRANTY/SERVICE POLICY  
HUMMINBIRD ONE YEAR FULL WARRANTY  
First year repairs (from original date of purchase) on your 100SX are  
absolutely free. This does not include physical damage to the unit or its  
accessory items. Any modification or attempt to repair the original  
equipment or accessories by unauthorized individuals will void the  
warranty. Return the warranty registration card and retain your bill of sale  
for warranty verification. Accessories not manufactured under the  
Humminbird trade name are not covered by our warranty. The customer  
is responsible for shipping charges to Humminbird. Humminbird will  
provide ground UPS or Parcel Post shipping back to the customer free of  
charge. This warranty applies to the original purchaser only.  
This warranty is in lieu of all other warranties expressed or implied and no  
representatives or persons are authorized to provide for any other liability  
in connection with the sale of our products. Humminbird reserves the  
right to perform modifications or improvements on its products without  
incurring the obligation to install the changes on units previously  
manufactured, sold, delivered, or serviced.  
THIS IS A FULL WARRANTY AS DEFINED BY THE FEDERAL WARRANTY  
ACT, EFFECTIVE JULY 4, 1975.  
SERVICE POLICY  
This Service Policy is valid in the United States only. This applies to  
Humminbird units returned to our factory in Eufaula, Alabama, and is  
subject to change without notice.  
All repair work is performed by factory-trained technicians to meet  
exacting factory specifications. Factory serviced units go through the same  
rigorous testing and quality control inspection as new production units.  
Even though youll probably never need to take advantage of our  
incredible service guarantee, its good to know that we back our units  
this well. We do it because you deserve the best. We will make every  
effort to repair your unit within three working days from the receipt of  
your unit. This does not include shipping time to and from our factory.  
29  
 
MAINTENANCE  
CUSTOMER SUPPORT  
Units received on Friday are usually shipped by Wednesday, units received  
Monday are usually shipped by Thursday, etc.  
We reserve the right to deem any product unserviceable when replacement  
parts are no longer reasonably available or impossible to obtain.  
After the original warranty period, a standard flat rate service charge will  
be assessed for each repair (physical damage and missing parts are not  
included). Please call our Customer Support Department to verify the  
service charge for your unit.  
If charges are not prepaid, the unit will be returned C.O.D. If you are  
experiencing problems related to bottom or depth readings, please send  
your transducer along with your unit when sending for repair.  
CUSTOMER SUPPORT  
If you have any questions, call our Humminbird Customer Support  
Hotline: 1-334-687-0503  
Throughout the U.S. and Canada, hours are Monday-Friday, 8:00 a.m. to  
5:00 p.m. Central time.  
If after reading Troubleshootingyou determine your unit needs factory  
service, please attach a description of the problem and send it with the  
unit to the address below.  
If you are including a check, please attach it to the unit.  
Humminbird  
Service Department  
108 Maple Lane  
Eufaula, AL 36027  
Further information on Humminbird products can be found at:  
30  
 
SPECIFICATIONS  
Operating Frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . 200 kHz  
Power Output . . . . . . . . . . . . . . . . . . . . . . . . . 300 Watts (RMS)  
2400 Watts (Peak to Peak)  
Area of Coverage . . . . . . . . . . . . . . . . . . . . . . . . 24° at -10 db  
Power Requirement . . . . . . . . . . . . . . . . . . . . . . . . 10 - 20 VDC  
Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . FSTN LCD  
LCD Matrix in pixels . . . . . . . . . . . . . . . . . . . . . . . 160 H x 160 V  
Viewing Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4" H x 3" V  
Mounting . . . . . . . . . . . . . . . . . . . . . . Quick Disconnect Mount  
Unit Size . . . . . . . . . . . . . . . . . . . . . . . 7⁵⁄₈"H x 7⁷⁄₈"W x 4³⁄₈"D  
Transducer (Standard) . . . . . . . . . . . . . . . . . . . . . . . . . . XT-6-24  
Transducer Cable Length . . . . . . . . . . . . . . . . . . . . . . . . . . . 20'  
Depth Ranges . 15', 30', 60', 120', 180', 240', 360', 480', & 600'  
Zoom Ranges . . . . . . . . . . .7¹⁄₂', 15', 30',45', 60', 90', 120', 150'  
31  
 
32  
 
Use with XT Series Transducer  
Part #531055-1 Rev. 11102E  
 

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