Humminbird DUAL BEAM 250DX User manual

Operations Manual

THANK YOU
Thank you for choosing Humminbird, America’s #1 name
in fishfinders. Humminbird has built its reputation by
designing and manufacturing top-quality, thoroughly
reliable marine equipment. Your Humminbird is designed
for trouble-free use in even the harshest marine
environment.
In the unlikely event that your Humminbird does require
repairs, we offer an exclusive Service Guarantee - free of
charge during the first year after purchase, and available at
a reasonable rate after the one-year period. Complete
details are included at the end of this manual.
We encourage you to read this operations manual carefully
in order to get full benefit from all the features and uses of
your Humminbird product. Also, to register your purchase
and help us learn more about you, please fill out the
warranty registration card at the back of this manual.
WARNING! This device should not be used as a
navigational aid to prevent collision, grounding,
boat damage, or personal injury. When the boat is
moving, water depth may change too quickly to
allow time for you to react. Always operate the boat
at very slow speeds if you suspect shallow water or
submerged objects.
WARNING: Dis-assembly and repair of this electronic unit should only be performed
by authorized service personel. Any modification of the serial number or attempt to
repair the original equipment or accessories by unauthorized individuals will void the
warranty. Handling and/or opening this unit may result in exposure to lead, in the form
of solder.
Warning: This product contains lead, a chemical known to the State of
California to cause cancer and birth defects and other reproductive harm.

INSTALLATION PREPARATION . . . . . . . . . . . . . . . . . . . . . . . 2
Parts Supplied . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Installation Overview . . . . . . . . . . . . . . . . . . . . . . . . . 2
Alternative Transducers and Mounting Methods. . . . . . 4
Transducer Exchange . . . . . . . . . . . . . . . . . . . . . . . . . 5
USING THE 250DX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
How Sonar Works . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Simulator Operation . . . . . . . . . . . . . . . . . . . . . . . . . . 7
What You See On Screen . . . . . . . . . . . . . . . . . . . . . . 8
Control Functions. . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Menu Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
ADVANCED FEATURES . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Using Diagnostic . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
MAINTENANCE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Customer Support . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
TABLE OF CONTENTS
REV 10822E

2
INSTALLATION PREPARATION
PARTS SUPPLIED
PARTS SUPPLIED
Before installing your 250DX, please ensure the following parts are
included in the box:
• 250DX fishfinder
• Transducer with 6m (20') of cable and mounting hardware kit
• Mounting system and mounting hardware kit
• 6m (20') power cable
• Publications kit
If any of these items is missing, contact your local distributor .
ACCESSORIES
Humminbird offers a wide assortment of accessories that complement and
expand the capability of your new 250DX. These accessories are designed
with the same high standards and are backed by the same one-year
warranty. 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 or factory direct through our number listed in
the Customer Support section.
INSTALLATION OVERVIEW
The 250DX 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.
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

3
INSTALLATION PREPARATION
INSTALLATION OVERVIEW
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 250DX includes a model XT-6-20
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 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).
Also, any air trapped in the
lamination of the fiberglass would
prevent the sonar signal from passing
through.
Transom Mounted Transducer
Inside the Hull Mounted Transducer

4
Inside the hull installations require no holes 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 250DX 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.
Thru-Hull Mounting
Thru-hull transducers install through a hole
drilled in the hull of the boat. Larger boats or
boats with inboard motors create turbulence
that make transom mounting ineffective. Also,
hulls that are very thick or are double layered, or
made from materials such as wood or metal,
INSTALLATION PREPARATION
ALTERNATE TRANSDUCERS AND MOUNTING METHODS

(which do not conduct sonar signals) make inside the hull mounting
inadvisable.
Thru-hull mounting may require the use of a fairing block to level the
transducer with the waterline. Also, since special tools and knowledge may
be required to perform this type of installation it is best to refer to a
qualified marine technician.
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 cata-
log or call Customer Support for information.
BEGINNING INSTALLATION
Now that you have determined the transducer mounting method, you can
begin installation of the 250DX. 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 front 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 boat’s battery)
• A 1-amp fuse
• A fuse holder (if you are wiring directly to the boat’s battery)
• Silicone sealant (for sealing drilled holes)
• 2-part, slow-cure epoxy (for inside the hull transducer installations)
INSTALLATION PREPARATION
TRANSDUCER EXCHANGE
5

USING THE 250DX
HOW SONAR WORKS
6
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
240' (70m) and back again in less than ¹⁄₄ of a second. It is unlikely that
your boat can "outrun" this sonar signal.
The 250DX is a dual frequency, dual beam unit, and generates two distinct
sonar signals - one narrow, one wide. Each signal is optimized for a
particular purpose. First, the center beam transmits at a frequency of 200
kHz in a 20 degree (narrow) symmetrical pattern for greater depth
capability and excellent detail. Information from this center beam is used to
draw the graphic representation of the bottom on the display.
Second, the wide beam transmits at a frequency of 83 kHz in a 53 degree
(wide) symmetrical pattern for greater area of coverage. Information from
the wide beam is used to accurately detect the presence and location of
fish. A wide beam has a large area of coverage but limited resolution of
detail. A narrow beam has excellent detail, but within a limited area
of coverage.
The combination of the two beams and dual frequencies provides the
combination of a large area of coverage and a high level of detail.

7
USING THE 250DX
SIMULATOR OPERATION
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 250DX 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 250DX.
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 the DOWN ARROW until “Simulator” is highlighted. When the
screen times out, the unit will be in simulator mode.
When in simulator operation, the 250DX 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.
When in simulator mode, the word “simulator” occasionally
scrolls across the display indicating the information on-screen is
not real sonar data.
FEATURE MEMORY
If your 250DX 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 unit’s 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 250DX in Simulator when no transducer is connected,
any selected options are lost when the unit is powered off. The 250DX 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 250DX 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 250DX uses a 128 V x 64 H matrix
FSTN LCD display. This display provides
outstanding viewability in all light
conditions over a wide range of
temperatures.
At initial power-up, the 250DX uses
settings that were set at the factory.
After initial use, the 250DX will
remember the settings you enter.
There are several elements on-screen
that are common to all modes of
operation.
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 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
8
USING THE 250DX
WHAT YOU SEE ON-SCREEN
Figure A