Raymarine L750 Operating instructions

Raymarine L750 Operating instructions
L750 Fishfinder
Operation Handbook
Raymarine
Contents
i
Contents
Chapter 1: Introduction .................................................................. 1
About the L750 Fishfinder ........................................................ 1
System Components ............................................................... 1
Standard Equipment .......................................................... 1
Standard Transducers ....................................................... 2
Optional Accessories ......................................................... 2
Chapter 2: Installation .................................................................... 4
About the Transducer .............................................................. 4
Selecting the Correct Type of Transducer .................................. 5
Installing a Thru-Hull Transducer .............................................. 6
Before You Begin the Installation......................................... 7
Selecting the Best Location for the Transducer..................... 7
Mounting the Fairing Block ................................................. 8
Installing a Thru-Hull Transducer ....................................... 10
Assembling the Transducer Bracket .................................. 11
Positioning the Transom-Mount Transducer ...................... 12
Mounting the Transom-Mount Transducer ......................... 13
Mounting the Optional Sidelooker Transducer ................... 15
Installation Notes – In-Hull Transducer .............................. 16
Installation Notes – Trolling Motor Transducer.................... 17
Installation Notes – Transducer for Speed and
Temperature Only ............................................................ 17
EMC Installation Guidelines ................................................... 17
Mounting the Display Unit ....................................................... 19
Standard Mount ............................................................... 19
Flush Mount .................................................................... 19
Installing the Transducer Cable .............................................. 21
Thru-Hull and Transom-Mount Installation ......................... 21
ii
L750 Fishfinder: Installation and Operation Handbook
Sidelooker Option ............................................................ 22
Installation with Separate Speed and
Temperature Sensors ...................................................... 23
Making the DC Power Connections ........................................ 23
Calibrating the Sensors .......................................................... 25
Chapter 3: Operating Instructions ............................................... 27
Controls on Display Unit ......................................................... 27
Turning the Power On and Off ................................................ 30
Turning the Power On – Initial Use .................................... 30
Turning the Power On – Routine Operation ........................ 31
Turning the Power Off ...................................................... 31
Setup Memory and Master Reset ........................................... 32
Operating Pages ................................................................... 32
Downlook Page ............................................................... 33
Fish Indications ................................................................ 37
Bottom Indications ........................................................... 38
Window Page .................................................................. 39
Digital Page ..................................................................... 41
Modifying Displays ................................................................ 42
Frequency Soft Key ......................................................... 42
Zoom Soft Key ................................................................. 44
Bottom Lock Soft Key ....................................................... 47
A-Scope (Bottom Coverage) Key ...................................... 49
Other Control Buttons ............................................................ 50
Display ............................................................................ 50
Gain/ Sensitivity ............................................................... 50
Range ............................................................................. 52
VRM ............................................................................... 53
Multi-purpose .................................................................. 54
Contents
iii
Alarms ............................................................................ 55
Mark ............................................................................... 57
About the Sidelooker Feature ................................................. 58
The Sidelooker Page ........................................................ 59
The Split-Screen Sidelooker Page .................................... 61
Turning On the Sidelooker Feature ................................... 61
Setting the Sidelooker Range ........................................... 61
Setting the Sidelooker Gain/Sensitivity .............................. 62
Chapter 4: Setup Instructions ...................................................... 63
The Setup Menus .................................................................. 63
Chart Speed Setting ......................................................... 63
Log Reset ........................................................................ 64
System Setup Menu ........................................................ 64
Resetting the Unit to Factory Defaults ..................................... 68
Default Settings ..................................................................... 68
Chapter 5: Maintenance and Troubleshooting ............................ 69
Cleaning Instructions ............................................................. 69
Troubleshooting Suggestions ................................................. 69
Servicing a Thru-Hull Transducer ........................................... 73
How to Contact Raymarine .................................................... 73
Parts Listing .......................................................................... 75
Chapter 6: Specifications ............................................................ 78
General Information ............................................................... 78
Fishfinder Functions .............................................................. 78
Connector Diagram ............................................................... 79
Dimensions ........................................................................... 80
Glossary of Terms ....................................................................... 81
L750 Fishfinder: Installation and Operation Handbook
iv
Figures
Fig. 2-1
Transducer Types ................................................... 4
Fig. 2-2
Thru-Hull Transducer .............................................. 6
Fig. 2-3
Best Transducer Locations ...................................... 8
Fig. 2-4
Installing a Fairing Block .......................................... 9
Fig. 2-5
Mounting the Transducer Correctly ........................ 11
Fig. 2-6
Assembling the Transducer Bracket ....................... 11
Fig. 2-7
Transducer Mounted on Transom .......................... 12
Fig. 2-8
Transducer Bracket, Side View .............................. 13
Fig. 2-9
Correct Mounting Position ..................................... 14
Fig. 2-10 Mounting the Transducer ...................................... 15
Fig. 2-11 Installing the Sidelooker Transducer....................... 16
Fig. 2-12 Suppression Ferrites ............................................. 18
Fig. 2-13 Mounting the Display ............................................. 19
Fig. 2-14 Flush-Mount Installation ........................................ 20
Fig. 2-15 Installing Cable on Transom .................................. 22
Fig. 2-16 Cable for Sidelooker Transducer ............................ 23
Fig. 2-17 Cable for Speed and Temperature Sensor ............. 23
Fig. 2-18 DC Power Connections ......................................... 25
Fig. 3-1
Display Panel ....................................................... 27
Fig. 3-2
Display Soft Keys .................................................. 32
Fig. 3-3
Downlook Page .................................................... 33
Fig. 3-4
Fish Indications ..................................................... 37
Fig. 3-5
Bottom Conditions ................................................ 39
Fig. 3-6
Window “A” Page .................................................. 40
Fig. 3-7
Digital Page .......................................................... 41
Fig. 3-8
Frequency Soft Keys ............................................. 42
Contents
v
Fig. 3-9
Split Frequency Feature ........................................ 43
Fig. 3-10 Zoom Feature On ................................................. 45
Fig. 3-11 Zoom Soft Keys .................................................... 46
Fig. 3-12 Bottom Lock Display ............................................. 48
Fig. 3-13 Bottom Lock Soft Keys .......................................... 48
Fig. 3-14 Downlook Page with A-Scope ................................ 49
Fig. 3-15 Gain or Sensitivity Soft Keys .................................. 52
Fig. 3-16 Range Soft Keys ................................................... 53
Fig. 3-17 Variable Range Marker ......................................... 53
Fig. 3-18 Multi-Purpose Soft Keys ........................................ 54
Fig. 3-19 Alarm Soft Keys .................................................... 55
Fig. 3-20 Mark Display ........................................................ 57
Fig. 3-21 Sidelooker Feature ............................................... 58
Fig. 3-22 Sidelooker Page ................................................... 59
Fig. 3-23 Window “D” Page with Sidelooker Information ........ 61
Fig. 4-1
Menu Soft Keys .................................................... 63
Fig. 4-2
Changing the Chart Speed Setting ......................... 63
Fig. 4-3
System Setup Menu ............................................. 65
Fig. 6-1
Connector Diagram .............................................. 79
Fig. 6-2
Dimensions .......................................................... 80
vi
L750 Fishfinder: Installation and Operation Handbook
Chapter 1: Introduction
1
Chapter 1: Introduction
About the L750 Fishfinder
The L750 Fishfinder is a system that uses sound waves (“sonar”) to
detect fish and show the bottom of a lake or sea. The system includes a
transducer and a display unit, connected by a cable. The transducer
sends high-frequency sound waves down into the water. These sounds
strike fish, the bottom, or other objects in the water, and return as
echoes. The Fishfinder then interprets these echoes and presents a
display.
The L750 Fishfinder can handle many different jobs:
• detect the presence of fish below the boat
• trigger an alarm when fish are found
• measure the depth of the water
• set alarms for minimum and maximum depth
• show the shape of the bottom
• determine whether the seabed is hard or soft
• measure the speed of the boat and the distance traveled
• show the water temperature
We are sure you will find the L750 Fishfinder to be one of the most useful
devices on your boat.
System Components
The L750 Fishfinder consists of a compact display unit connected to a
transducer. The transducer is attached to the boat and extends into the
water.
Standard Equipment
When you unpack your L750 Fishfinder, you should find the following
standard equipment in the carton. If any items are missing, please notify
your Raymarine dealer immediately, or contact the Customer Service
Department at Raymarine at 1-800-539-5539, ext. 2333. Please provide
the serial number of the Fishfinder when reporting any missing items.
L750 Fishfinder: Installation and Operation Handbook
2
Description
Part No.
L750 Fishfinder display unit
M78956
Sun cover
D331
Bracket assembly
W143
Two trunion knobs
W145
Three #8 x 3/4” mounting screws
G625774-1
Transducer adapter cable
G625877-1
DC power cable
W144
Instruction manual
G625773-2
Quick reference guide
G626492-1
Standard Transducers
Depending on which model of the L750 you have purchased, the box will
include one of the transducers listed below:
Description
Part No.
Transom-mount transducer (with speed
and temperature sensors, including
mounting bracket and hardware)
M78898
Bronze thru-hull transducer (with
speed and temperature sensors)
M78923
Optional Accessories
Optional accessories are available from your Authorized Raymarine
Dealer. Accessories may also be purchased directly from Raymarine
by contacting the Customer Service Department at 1-800-539-5539,
extension 2333.
Description
Part No.
Sidelooker transom-mount transducer
M78930
Sidelooker transducer for trolling motor
(all-in-one unit senses depth below boat,
with Sidelooker and temperature sensor,
including mounting hardware)
M78929
Extension for transducer cable (15 ft, 5 m)
M99-140
Extension for transducer cable,
for Sidelooker transducer (15 ft, 5 m)
M99-139
Chapter 1: Introduction
3
Flush-mounting kit (with hardware and
mounting template)
M92708
Fairing block for M78923 thru-hull
transducer (Lexan®)
M99-142
Low profile plastic thru-hull transducer
(Valox® plastic, sensor for depth only)
M78922
Bronze thru-hull transducer
(sensor for depth only)
M78921
In-hull/trolling motor transducer (for installation in
fiberglass hull only, or mounting on trolling motor,
including hardware for either installation)
M78928
Angled in-hull transducer (for installation
in fiberglass hull only, where deadrise
angle is 10° to 22°)
M78946
Plastic thru-hull transducer (Valox® plastic, with
speed and temperature sensors, used with depthonly transducers M78922, M78928, M78946)
M78937
Transom-mount speed and temperature
sensor (used with depth-only transducers
M78922, M78928, M78946)
M78936
Replacement transom transducer
mounting bracket kit
M99-148
Transducer switch box (select between two L750
Fishfinder displays, using one transducer)
M99-136
Replacement paddle wheel kit (for transommount transducer)
M99-143
Replacement paddle wheel kit
(for thru-hull transducer)
M99-144
Note: Refer to page 75 for a list of repair parts.
L750 Fishfinder: Installation and Operation Handbook
4
Chapter 2: Installation
The installation process has four parts:
• Mounting the transducer
• Mounting the display unit
• Connecting the cables for the transducer and power supply
• Calibrating the display unit
About the Transducer
Several different kinds of transducers can be used with this unit. The
“thru-hull” and “transom-mount” types are used most often. Other types
are shown in Fig. 2-1.
Thru-hull
transducer
Fairing for
thru-hull transducer
Transom-mount
transducer
Low profile
transducer
In-hull
transducer
Sidelooker
transducer
Fig. 2-1 Transducer Types
Most transducer types can measure the water depth. Some of the
transducers also have two other sensors: a paddle wheel which detects
the speed of the boat, and a sensor for the water temperature. The
display unit uses the speed information to calculate the distance the boat
has traveled.
The transducer is very important to the operation of the Fishfinder. It is
also important that you mount the transducer correctly. The transducer
Chapter 2: Installation
5
will give the most reliable readings if it looks into water which is smooth
and undisturbed. If you place the transducer so bubbles or turbulence
flow across the face of the unit, the system may give inaccurate
readings.
There are three important rules for placing any type of transducer:
• The transducer should be continuously covered by water when the
boat is moving. (If the transducer is mounted near the side of the
boat, it may be exposed when the boat is turning.)
• The transducer should be placed where turbulence or bubbles will not
pass directly over the face of the unit. Don’t place the transducer
behind any running strakes, intakes, or thru-hull fittings which create
turbulence.
• The transducer should be mounted where it will not be affected by the
wash from the propeller(s).
Selecting the Correct Type of Transducer
Before you begin the installation, double-check to be sure you have the
correct type of transducer. Each kind of transducer is designed for a
particular type of use. In this manual we will include detailed mounting
instructions for the thru-hull and transom-mount transducers. We will
also include some general information on the other types. For detailed
information on these other transducers, see the instructions which are
packaged with the unit.
Use a thru-hull transducer if –
. . . your boat has a straight-shaft inboard engine. This type of
transducer is installed in a hole drilled through the hull.
Use a transom-mount transducer if –
. . . your boat has an outboard or inboard-outboard engine(s) only. This
type of transducer must be mounted ahead of or beside the propeller(s).
Do not use this type of transducer for a boat with a straight-shaft inboard
engine.
Use an in-hull transducer if –
. . . you have a high-speed boat or if, for some reason, you cannot use a
transom-mount or thru-hull transducer. The hull may be no more than 1"
thick.
L750 Fishfinder: Installation and Operation Handbook
6
Use a trolling motor transducer if –
. . . you want to attach the transducer to a trolling motor.
Use a Sidelooker transducer if –
. . . you need a way of searching for fish on either side of the boat. This
type of transducer is attached to the bracket of the transom-mount
transducer.
Installing a Thru-Hull Transducer
This unit may be used with a thru-hull transducer. Please read this
section completely before starting the installation. Normally, this type of
installation is performed by a professional.
3.13" dia.
(79 mm)
5.24"
(133 mm)
2.00" dia.
(51 mm)
1.05"
(27 mm)
Fig. 2-2 Thru-Hull Transducer
5.50"
(140 mm)
Chapter 2: Installation
7
Before You Begin the Installation
Follow these instructions if you are installing the thru-hull transducer.
Here are some rules to remember:
• Do not install the thru-hull transducer, then leave your boat in the
water for any amount of time without checking for leaks.
• The position of the transducer is especially critical on high speed
vessels (capable of more than 20 knots). Check the locations of the
transducers on similar boats before installing the transducer on your
own boat. Choose the location which will offer the best performance.
• If the hull of your vessel has a core-type hull, you will need to follow
some special mounting procedures. (If the core material is allowed to
remain wet, it may rot and weaken the hull.) If you are in any doubt
about this kind of installation, consult your boat representative or your
Raymarine dealer.
A set of installation instructions will be packaged with each transducer.
These will give you more detailed information than we can include here.
The notes in this section will help you through the most important parts of
the installation process. (If the instructions in the package are different
from the notes in this manual, follow the packaged instructions.)
Selecting the Best Location for the Transducer
Follow these instructions if you are installing the thru-hull transducer.
Here are some important rules for mounting the transducer:
• For planing hulls – Install in the flat planing area near the stern.
Always install forward of the propeller(s) and shaft(s).
• For small displacement hulls – Install near the centerline of the hull
and 1/3 of the way forward from the stern. Always install forward of
the propeller(s) and shaft(s).
• For large displacement hulls – Install near the centerline of the hull
and 1/3 of the way aft from the bow. Always install forward of the
propeller(s) and shaft(s).
• For sailboats – Install forward of the leading edge of the keel, to one
side and near the centerline of the hull.
• Place the unit where bubbles will not pass over the front of the
transducer (especially at higher speeds). Avoid any bubbles caused
by shaft struts, fittings, or other transducers with paddle wheels. If you
notice any erosion of the paint on the hull, this is a sign of turbulence or
bubbles.
L750 Fishfinder: Installation and Operation Handbook
8
• Choose a location where the transducer will always be covered by
water.
• The beam from the transducer should not be blocked by a keel or
prop shaft.
• Choose a location where you can easily reach the transducer from
inside the vessel. This will allow you to make adjustments and
periodic inspections. Allow at least 6" (152 mm) of headroom above
the transducer.
• The “deadrise” is the angle or slope of the bottom of the hull in the
side-to-side direction. Try to find a mounting location with the smallest
deadrise angle.
Sailboats
Tri-hulls
Best locations for
thru hull
transducers
Planing hulls
Fig. 2-3 Best Transducer Locations
Mounting the Fairing Block
Follow these instructions if you are installing the thru-hull transducer.
The transducer should aim straight down (within 10°). If the bottom of
the hull is sloped more than this, a fairing block may be necessary to
Chapter 2: Installation
9
keep the transducer perpendicular to the waterline. A fairing block which
can adjust for angles of up to 25° is available from Raymarine.
1. Measure the deadrise angle of the hull at the selected mounting
point.
2. Cut the block to a shape which fits the exact contour of the hull. The
cut-out portion can be mounted inside the hull to provide additional
support for the transducer once it is mounted.
3. Attach the fairing block to the hull as firmly as possible. This fairing
block must be able to resist the drag of the water against the hull, and
must also be completely waterproof.
Upper part of
transducer
Inner part
of fairing
block
Section
of hull
Outer part
of fairing
block
Lower part of
transducer
(front view)
Fig. 2-4 Installing a Fairing Block
10
L750 Fishfinder: Installation and Operation Handbook
Installing a Thru-Hull Transducer
Follow these instructions if you are installing the thru-hull transducer.
Once you have decided where to install the transducer, drill the hole for
the part.
1. Begin by drilling a small pilot hole (1/8" or 3 mm) from the inside of
the hull. (This small hole can be filled easily if the mounting location
is not suitable.) Before you drill the hole, be sure you will be able to
reach the large nut on the top of the transducer, once it has been
mounted. Also be sure there will be enough clearance for the cable.
If there is a strake or other feature on the hull, drill from the outside of
the hull instead.
2. Drill a larger hole from the outside of the hull using a 2" (50 mm) hole
saw or paddle bit.
3. Uncoil the transducer cable. Remove the large hex nut from the
housing and slide it over the end of the cable.
4. Thread the cable through the hole to the inside of the hull. Never pull
or carry the transducer using the transducer cable. This may break
the wiring connections inside the cable. Never hold the transducer in
place by pulling on the transducer cable.
5. Apply a thin layer of sealant (1/8" or 3 mm) to the transducer
between the upper flat surface of the transducer and the fairing
block. Use a high-quality marine sealant suitable for underwater
use. Also apply a thin layer up the side walls. This should cover all of
the threads where the part will touch the hull material, plus an
additional 1/4" (6 mm). This will seal the threads for the large hex
nut.
6. Push the transducer housing (with the sealant applied) into the hole
from the outside of the hull. Twist the housing slightly to squeeze out
any excess sealant and to get a good seal. Be sure that the
transducer is aligned so that the correct part of the unit is toward the
bow of the vessel. See Fig. 2-5. Hold or prop the transducer in place
temporarily.
7. Go to the inside of the hull and slide the hex nut over the end of the
cable. Fit the hex nut over the end of the transducer and tighten it.
(On a vessel with a wooden hull, do not tighten the nut completely
right away. Allow some time for the wood to swell after the vessel is
put in the water.
8. Remove any excess sealant from the outside of the unit to assure
smooth water flow over the transducer.
Chapter 2: Installation
11
9. As soon as the boat is placed in the water, check for leaks. Check
again within 3 to 5 hours. (You may not be able to see a small leak
right away.) If there are any leaks, you must repeat the installation
procedure.
This end forward
Paddle wheel
assembly near
rear.
Fig. 2-5 Mounting the Transducer Correctly
Assembling the Transducer Bracket
Follow these instructions if you are installing the transom-mount
transducer.
Fit together the two parts of the transducer bracket as shown in Fig. 2-6.
When the installation is complete, the parts snap together as shown.
LIKE THIS!
Attach the
two parts
NOT THIS!
Bracket is installed
upside down
Lower the transducer
and snap in the
release clip
Fig. 2-6 Assembling the Transducer Bracket
12
L750 Fishfinder: Installation and Operation Handbook
Positioning the Transom-Mount Transducer
Follow these instructions if you are installing the transom-mount
transducer.
Begin by finding the best location for the mounting bracket. Here are the
rules:
• If your boat has one propeller (outboard or inboard-outboard), mount
the transducer about 18" (455 mm) to the side of the centerline of the
boat. See Fig. 2-7. Choose the side that is on the downstroke of the
propeller. (This is usually the starboard side of the boat.) This will
reduce any interference caused by air bubbles.
• If your boat has twin propellers (outboard or inboard-outboard), place
the transducer near the centerline of the boat.
• If the propeller can be turned to steer the boat, allow at least 2" (50
mm) beyond the swing radius of the propeller. This will prevent the
propeller from damaging the transducer when it is turned.
• Do not mount the transducer behind any hull fittings, intakes, or other
parts which extend from the hull. These may cause turbulence or air
bubbles.
• The bracket has a quick-release mechanism. This prevents damage
by allowing the transducer to flip up if it hits any debris or the bottom.
See Fig. 2-8. Allow enough clearance above the transducer so that it
can swing upward completely. This is about 10" (254 mm) measured
from the bottom of the transom.
• If the boat will be carried on a trailer, be sure the transducer will not hit
any rollers, bunks or fittings on the trailer.
Fig. 2-7 Transducer Mounted on Transom
Chapter 2: Installation
13
Allow a clearance
of at least 10
inches (254 mm)
Transducer in
released position
10"
(254 mm)
Fig. 2-8 Transducer Bracket, Side View
Mounting the Transom-Mount Transducer
Follow these instructions if you are installing the transom-mount
transducer.
1. On a boat with a fiberglass hull, the leading edge of the transducer
should extend 1/8" (3.2 mm) to 1/4" (6 mm) below the bottom edge
of the hull. See Fig. 2-9. On an aluminum hull, the transducer
should extend a bit more – 1/4" (6 mm) to 3/8" (9 mm). If the boat will
be operated at high speeds, the transducer may be mounted closer
to the centerline of the hull.
2. The lower surface of the transducer should tilt down toward the rear
at a slight angle (2° to 5°). The mounting bracket includes a wedge.
Depending on the angle of the transom on your boat, you may need
this wedge to get the correct angle for the bottom of the transducer.
3. Looking at the rear of the boat, be sure the bracket is vertical
(perpendicular to the water line).
4. Hold the bracket (and the wedge, if used) against the transom and
trace the positions of the screw slots.
5. Remove the bracket. See Fig. 2-10. The screws in the outer slots
should be placed about 1/4" (6 mm) up from the bottom of each slot.
The screw in the center slot should be placed 1/4” (6 mm) down from
the top. (This will allow you to adjust the bracket up or down a bit.)
Drill pilot holes 3/4" (19 mm) deep. Use a 9/64" (3.5 mm) drill bit. To
prevent drilling too deeply, wrap masking tape around the drill bit
about 7/8" (22 mm) from the tip. Drill in only as far as the tape
marker.
If you are attaching the bracket to a fiberglass hull, you can minimize
any surface cracking of the gel coat. Before drilling each pilot hole,
drill a shallow hole (chamfer) at each location about 1/16" (1.5 mm)
deep. Use a 1/4" (6 mm) drill bit.
L750 Fishfinder: Installation and Operation Handbook
14
6. Attach the bracket to the hull using the panhead screws with flat
washers. Before you tighten the screws, apply a good-quality
marine sealant to the pilot holes. This will protect the hull from water
penetration. Do not tighten the screws completely yet.
7. Move the bracket up or down so that the leading edge of the
transducer has the clearance shown in Fig. 2-9.
8. Once the bracket is in the correct position, you can tighten the
screws.
Average transom angle–
no wedge necessary
Vertical transom –
place wedge this way
2 to 5
2 to 5
Sloping transom–
place wedge this way
2 to 5
For fiberglass hull – 1/8" to 1/4" (3.2 to 6 mm)
For aluminum hull – 1/4" to 3/8" (6 to 9 mm)
No!
No!
The bow of the transducer
is above the bottom of the
transom, creating
cavitation.
Rivets on the hull are
creating bubbles.
Lower the transducer
a bit.
Fig. 2-9 Correct Mounting Position
No!
The rear of the transducer
is too high, creating
cavitation.
Chapter 2: Installation
15
Insert screws 1 and 3
1/4" from the bottom of
slots, and screw 2
1/4" from the top of the
slot to allow room for
adjustment.
1
2
3
Correct
alignment
If screws are inserted
this way, it won’t be
possible to make the
height adjustment.
Incorrect
alignment
Fig. 2-10 Mounting the Transducer
Mounting the Optional Sidelooker Transducer
1. The Sidelooker transducer allows the display unit to check the water
to either side of the boat. This is helpful when you are looking for fish
near river banks, or under docks or piers.
2. The Sidelooker transducer is attached to the same mounting bracket
used with the transom-mount transducer. See Fig. 2-11. Begin by
installing the transom-mount bracket as described earlier.
3. Attach the Sidelooker transducer to the top of the transom mounting
bracket. Use the four panhead screws supplied. The fit should be
snug, but do not overtighten the screws.
4. If you are installing the optional Sidelooker transducer, there will be
two transducer cables. Run the second cable beside the cable for
the transom-mount transducer.
5. Before the Sidelooker features can be used, the function must be
turned on. There is a line for this in the System Setup menu. See
Section 4.
16
L750 Fishfinder: Installation and Operation Handbook
Fig. 2-11 Installing the Sidelooker Transducer
Installation Notes – In-Hull Transducer
Detailed instructions for this installation will be included with the
transducer. In this section, we will note just a few important points.
1. Choose the best mounting location:
For outboard powerboats – Install as far aft as possible
For inboard/outboard powerboats – Install close to the engine(s)
For inboard powerboats – Install forward of the propeller(s) and
shaft(s)
For sailboats – Install near the centerline of the hull and forward of
the leading edge of the keel
2. An in-hull transducer may only be installed in a fiberglass hull which
is no more than 1" (25 mm) thick. The in-hull transducer may not be
installed in wood or aluminum hulls.
3. Use the standard in-hull transducer if it will be installed in a flat part of
the hull, or a section with no more than 10° of deadrise. Use the
angled in-hull transducer if the mounting location has up to a 22° of
deadrise.
4. Do not try to compensate for the angle of the hull by fairing the epoxy
adhesive on the face of the transducer.
5. Use the epoxy supplied with the in-hull transducer, or an equivalent
Chapter 2: Installation
17
epoxy glue. Do not use any other type of adhesive, including silicone
or RTV adhesive.
Installation Notes – Trolling Motor Transducer
Detailed instructions for this installation will be included with the
transducer. This type of transducer is attached to the horizontal gear
case of the trolling motor. The installation is simple, but is important to
keep the transducer away from the wash from the propeller, and from
turbulence caused by parts of the hull.
Installation Notes – Transducer for Speed and
Temperature Only
This type of transducer may be used with a thru-hull transducer which
reads depth only. The speed/temperature transducer is attached to the
transom of the boat. Detailed instructions for this installation will be
included with the transducer. The cable for this transducer uses a “Y”
connector. See the notes on “Installing the Transducer Cable.”
EMC Installation Guidelines
When different types of marine electronic equipment are mounted
closely together in a tight space, they may interfere with each other. The
design and manufacture of this unit follow industry standards for
“Electromagnetic Compatibility” (EMC). However, it is important to
install the unit correctly to ensure the best possible performance. Below
is a list of some of the factors which could affect the operation of the
product. Some of these factors may affect the way you install the
Fishfinder and the wiring cables.
• Place the display unit and the power and signal cables at least 3 ft
(1m) from any equipment transmitting radio signals, or any cables
carrying radio signals. This includes VHF radios, cables and
antennas. In the case of SSB radios, the distance should be
increased to 7 ft (2m).
• Allow a space of at least 7 ft (2m) from the path of a radar beam.
Normally, a radar beam will spread about 20° above and below the
radiating element.
• The power for the display unit should be supplied from a different
battery than the one used to start the engine. If the voltage to the
Fishfinder unit drops below +10.7V DC, this could cause the unit to
reset. This will not damage the equipment, but it may cause the loss
18
L750 Fishfinder: Installation and Operation Handbook
of some information, and it can change the operating mode.
Avoid running the Fishfinder power wires near the power wiring for any
radar, radio, or Loran-C units. If possible, wire the Fishfinder power
wires to a separate circuit breaker.
• If the transducer cable runs near another electrical wire, it may pick up
electrical interference or “noise.” To reduce this, try to keep the
transducer cable separated as far as possible from all other wires.
This is especially important with wiring for the boat’s ignition,
alternator, or tachometer. It is also helpful to keep the transducer
cable away from the Fishfinder power cable. If it is necessary to run
the transducer cable across any wires, make the crossing at a right
angle.
• Use only genuine Raymarine cables. During the installation, do not
cut the transducer cable or remove the connector. Do not try to
shorten or splice the cable. The transducer cable includes several
wires, along with shielding and insulation. If the cable is cut, it cannot
be repaired. (Cutting the cable will also void the warranty.) During
installation, if you need to drill any holes for the cable, they must be
large enough to accept the connector. This will allow you to make the
installation without cutting the wire.
• A “suppression ferrite” may be attached to one of the cables. See Fig.
2-12. If you must remove the ferrite during installation, be sure to
reassemble it in the same position.
Fig. 2-12 Suppression Ferrites
Chapter 2: Installation
19
Mounting the Display Unit –
Standard Mount
You may mount the display unit on any flat surface using the bracket
supplied. See Fig. 2-13. (There is also an optional kit which allows you
to flush-mount the display in a flat panel or dashboard). Follow these
instructions if you are using the standard mounting bracket:
1. The “LCD” type display used on this unit is easier to see from certain
angles. Before selecting a permanent mounting location, make
temporary power connections and turn on the unit. This will allow
you to test the visibility of the display from several different angles.
2. Separate the display unit from the bracket by unscrewing the two
attaching knobs.
3. Mount the base of the bracket using the supplied screws.
4. Attach the unit to the bracket again using the knobs.
5. Adjust the display unit for the best viewing angle. You can tilt the
display up or down.
Fig. 2-13 Mounting the Display
Flush Mount
In order to do this installation, you will need the optional flush mounting
kit. See Fig. 2-14.
1. Select a mounting location on the dashboard or control panel.
Choose a clear, flat area at least 9" wide x 8" high (230 mm x 210
mm). Be sure you will also have at least 6" (152 mm) of clearance
20
L750 Fishfinder: Installation and Operation Handbook
behind the area where the display unit will be mounted. It is a good
idea to drill a small pilot hole in the center of the mounting area. Be
sure there are no hidden electrical wires or other items behind the
point where you plan to mount the display unit.
2. Unpack the flush mounting kit. A mounting template is supplied with
the kit. Tape this over the selected location on the panel and trace
around the opening for the display unit. Also mark the locations of
the holes for the screws.
3. Make the cutout for the display. Drill two 1/2" (13 mm) pilot holes at
the two corners shown at the edges of the cutout area.
4. Cut along the outline of the opening with a small saw.
5. Separate the display unit from the mounting bracket. Set the display
unit into the opening and check the fit.
6. Attach the two flush mount handles using the knobs.
7. Lower the handles to tighten and hold the unit in place.
9mm (0.35 in)
maximum
Fig. 2-14 Flush-Mount Installation
8. Once the DC wiring is complete, finish the installation. A suitable
sealant may be used between the gasket and the console to prevent
moisture from entering the console. Fit the display into the cutout
again. From the rear, screw the nuts securely onto the threaded
studs to hold the unit in place.
Chapter 2: Installation
21
Installing the Transducer Cable Thru-Hull and Transom-Mount Installation
A 20 foot length of cable, with the connector attached, is supplied with
the transducer. During the installation, do not cut the transducer
cable or remove the connector. Do not try to shorten or splice the
cable. The transducer cable includes several wires, along with
shielding and insulation. If the cable is cut, it cannot be repaired.
(Cutting the cable will also void the warranty.) During installation, if you
need to drill any holes for the cable, they must be large enough to accept
the connector. This will allow you to make the installation without cutting
the wire.
1. For a transom-mount installation – Route the cable up and over
the top edge of the transom. See Fig. 2-15. Secure the cable using
cable clamps. (These clamps are available from your local marine
equipment supplier.)
If you do not want to expose the cable on the deck, you may drill a
new hole (3/4" or 19 mm) through the transom for the cable.
(Remember – this hole must be large enough to accept the cable
with the connector attached. Do not cut the cable!) To seal the
opening, use a feed-thru cap where the cable passes through the
transom.
2. For either type of installation – Run the cable through the interior
of the boat. Follow the suggestions in the section on “EMC
Installation Guidelines.”
3. Be careful not to tear the cable jacket when passing it through
bulkheads and other parts of your boat. Secure the cables in place
using tywraps or lacing twine. Coil the extra cable and tie it out of the
way.
4. If the 20 foot transducer cable is not long enough, a 15 foot extension
cable (5M) is available from your Raymarine dealer (part no. M99139). When you attach the extension cable, be sure that the
connections are tight and watertight. Use Dow Corning DC-4 or an
equivalent sealing compound to protect the connector assemblies.
5. At the rear of the display unit, the transducer cable plugs into a short
section of wire called a “pigtail.” Plug the transducer cable into the
pigtail, then plug the pigtail into the rear of the display unit. If you
need to disconnect the transducer cable, try to do this at the pigtail
rather than the rear of the display unit.
L750 Fishfinder: Installation and Operation Handbook
22
Important! The L750 Fishfinder is sometimes used with the
Raymarine SL70 “Pathfinder” radar display. The two units have the
same case design. Each unit has a large connector on the rear of
the case. On the radar unit, this connector is used to bring in the
radar signals. On the Fishfinder, this connector is used for the
transducer cable. If you have installed the two units side by side, be
very careful not to attach the radar cable to the Fishfinder, or vice
versa. This can cause permanent damage to either unit. The cable
for the radar unit has white insulation.
Cable feed-thru
cap
Cable clamp
1" (25 mm)
Hull projections
Fiberglass: 1/4" (6mm)
Aluminum: 1/2" (13 mm)
Fig. 2-15 Installing Cable on Transom
Sidelooker Option
1. If the installation includes the optional Sidelooker transducer, there
will be two transducer cables. See Fig. 2-16. The cable from the
Sidelooker includes a “Y” connector.
2. Plug the cable from the depth transducer into the open end of the “Y”
connector.
Chapter 2: Installation
Sidelooker
transducer
23
Depth
transducer
Fig. 2-16 Cable for Sidelooker Transducer
Sensor for
speed and
temperature
Sensor for
depth only
Fig. 2-17 Cable for Speed and
Temperature Sensor
Installation with Separate Speed and Temperature
Sensors
1. Optional depth-only and speed- and temperature-only transducers
are available for the L750 Fishfinder. In this optional configuration the
separate transducers are connected via a “Y” type receptacle cable
located on the optional speed- and temperature-only transducer
cable.
2. Plug the cable from the depth-only transducer into the receptacle
connector on the optional speed- and temperature-only transducer.
The speed- and temperature-only transducer then connects to the
“pigtail” which runs to the transducer connector of the L750
Fishfinder. This is shown at left in Fig. 2-17.
Making the DC Power Connections
1. The display unit is designed for use on boats with 12V DC power
systems. (The unit can operate as long as the actual voltage is
between 10 and 16V DC.) The display unit can be wired to a
negative-ground system, or both the negative and positive supply
lines may be “floating” above ground. This unit is not intended for
use on boats with positive ground.
24
L750 Fishfinder: Installation and Operation Handbook
2. The 6-foot power cable supplied with the display unit should reach
the source of DC power. Connect the power leads directly to the
main battery isolation switch or breaker, or route the power leads to
the DC power distribution panel.
3. It is very important that you connect the power leads correctly. See
Fig. 2-18. In the power cable, there are several twisted pairs of small
wires which are not used in this application (orange, yellow, green
and blue insulation). You can clip off the ends of these small wires.
Only the large red and black wires are used to supply power to the
Fishfinder.
At the power source, connect the red wire to the positive terminal
(+), and the black wire to the negative terminal (-). The negative
terminal may also be called “ground” or “earth.” (The display unit is
internally protected if you accidentally reverse the polarity of the
power wires.)
4. Attach the red or positive wire to a 5 amp circuit breaker. If the unit is
connected directly to the boat’s battery, include a 2 amp in-line fuse.
(In-line fuses are available at most marine supply stores.)
5. To prevent any interference or electrical noise, separate the
Fishfinder power wiring as much as possible from other devices.
See the section on “EMC Installation Guidelines.”
6. If you need to extend the power wiring by more than 10 feet, use a
larger wire size. This will allow the wires to deliver the correct voltage
in spite of the longer wire distance. For runs of 20 to 35 feet, use #14
AWG.
If you extend the power wiring, be sure all electrical connections are
solid and durable. Soldering is the best way to make these
connections. Insulate all connections using heat-shrink tubing or
electrical tape. You may also use crimp connectors or a terminal
strip, but be sure to use good-quality marine-grade parts.
7. At the rear of the display unit, plug in the power cable.
Note - Press firmly when inserting the power cable and transducer
cable to ensure a tight seal.
8. When you press the Power button, the display unit should turn on. If
the unit will not turn on and you suspect that you may have reversed
the power connections, check the DC power lines all the way back to
the battery. If the polarity is not correct, reconnect the leads properly
and try again.
Chapter 2: Installation
25
Power
connector
Transducer
connector
Shield connected
to RF ground
5A fuse or
circuit
breaker
To
transducer
+ connection
to red wire
12V DC
source
Small orange, yellow,
green and blue wires
not connected
- connection
or ground
to black wire
Fig. 2-18 DC Power Connections
Calibrating the Sensors
The transducers most often used with this unit include sensors for boat
speed and water temperature. These sensors are normally very
accurate, but you may want to calibrate them.
The speed indication on your Fishfinder is usually very accurate.
However, there are some special cases where the speed reading may
be high or low. This means that the speed of the water past the
transducer may not be the same speed that your boat moves through
the water. The hull of the boat may have a shape which channels water
past the transducer at a speed which is faster or slower than normal.
1. To calibrate the speed sensor, set up a course between two known
points. As markers you can use buoys, range markers, or
landmarks. Measure the length of time the boat takes to cover a
known distance.
26
L750 Fishfinder: Installation and Operation Handbook
2. You may also use locations indicated by a G.P.S. or Loran unit. (If
you choose this method, remember that these devices measure
“speed over ground” or “speed over the bottom.” Tides, currents, or
winds can create a difference between the FishFinder’s “speed
through water” measurement and the boat’s “speed over ground.”
Before calibrating using a G.P.S. or Loran unit, wait for still water or
slack tide conditions.
3. If the display unit is reading high or low, you can correct for this using
the entry for “Speed Cal.” (To reach Speed Cal, go to the System
Setup display. This is described in Section 4.) The entry for Speed
Cal is a percentage. An entry of “100” equals 100%, meaning that
there is no correction. If the display unit is producing a low reading,
use a higher value for Speed Cal. If the display unit is reading high,
use a smaller number for Speed Cal. You may enter any value
between 75 and 125.
4. The temperature sensor is usually very accurate, but you can adjust
the calibration using the entry for “Temp Cal.”
Final note: After you finish the installation, please remember to fill out
the Warranty Card included with this manual.
Chapter 3: Operating Instructions
27
Chapter 3: Operating Instructions
In this section of the manual, we will explain how to operate the unit.
(Setup instructions are detailed in the next Chapter.) Below you will find
some short descriptions of the controls on the display unit. We have
included more detailed descriptions in the following sections.
Controls on Display Unit
Display area
The various displays or “pages” produced by the unit appear here. (You
can step through these pages using the “soft keys” at the bottom of the
display.) Other kinds of display information may also appear in the
display area. The system includes several setup displays which can be
used to change some of the controls used by the unit. See Chapter 4.
When the Simulator Mode is switched on, the unit generates its own
display without receiving signals from the transducer. This mode is used
for sales and training.
Display area
Gain
GAIN
DISPLAY
VRM/EBL
MARKS
Display
VRM
Marks
MULTI
Multipurpose
RANGE
ALARMS
Range
Alarms
Track pad
Power
ENTER
POWER
Soft keys
Fig. 3-1 Display Panel
CLEAR
MENU
Menu
Clear
Enter
L750 Fishfinder: Installation and Operation Handbook
28
Trackpad
The Trackpad is used when you are setting up the unit. We will explain
the details in Chapter 4.
For example, when you are looking at the System Setup menu, you use
the up-and down- controls on the Trackpad to move to the item you want
to change. Next, you use the left- and right- controls to select the option
you want.
When you are using the manual Zoom feature, you can use the
Trackpad to move the Zoom area up or down.
Soft Keys
Depending on the display you are looking at, the unit will present
different options or “Soft Keys” at the bottom of the display area. By
using the Soft Keys, you can call up different displays or change the setup of the unit. To select one of the Soft Keys, press the button below the
image on the display. Sometimes you must press the same Soft Key a
second time to make a choice or select an option. (These are called Soft
Keys because the functions change from one display to the next, and
are controlled by the software running inside the Fishfinder.)
The display shown in Fig. 3-1 shows four Soft Keys. These are
explained in the following sections.
Frequency
The transducer can use two frequencies - 50 kHz for wide coverage, or
200 kHz for a detailed view. You can also set the unit to use both
frequencies at the same time (“dual frequency”). (For more on this, see
“Choosing the Frequency.”)
Zoom
The Soft Key for the Zoom feature appears on the main Downlooker
display. The Zoom feature allows you to select an enlarged or magnified
view of a section of the display.
Bottom Lock
The Soft Key for the Bottom Lock feature appears on the main
Downlooker display. The standard Downlooker display is a “top-down”
view, as if it was seen from the surface of the water. The Bottom Lock
display shows a “bottom-up” view. The bottom is used as the reference,
Chapter 3: Operating Instructions
29
and is shown as a straight line. Echoes from objects directly above the
bottom are indicated on the display.
A-Scope
The Soft Key for the A-Scope feature appears on the main Downlooker
display. The A-Scope feature presents a “real time” display of the area
under the boat.
Power
This button controls the power supply to the unit.
Gain/sensitivity
The “Gain” or “Sensitivity” setting controls the ability of the unit to tell the
difference between echoes of different strengths.
Display
The Display button allows you to step between the main displays or
“pages” presented by the unit.
VRM
“VRM” means “Variable Range Marker.” This is a way of finding the
depth of an object on the display. Using the VRM button, you can create
a line on the display, and move it up or down to match the depth of the
object you are checking.
Mark
The Mark button allows you to set a vertical marker on the display over a
selected point on the bottom. As the display scrolls past, the vertical line
keeps the same relative position.
Multi-purpose
This button allows you to adjust the contrast and backlighting level used
for the display.
Range
The “Range” changes the depth scale which can be displayed on the
screen.
L750 Fishfinder: Installation and Operation Handbook
30
Alarms
The Fishfinder has a deep-water alarm, a shallow-water alarm, and a
“Fish” alarm which is triggered when fish are present. This button allows
you to set these alarms.
Enter
After you make a change in a menu, press Enter to record the change
and return to the normal display.
Clear
If you make a change, but do not want to save it, press Clear.
Menu
The Menu button allows you to set up several functions on the unit. It
also allows access to the System Setup menu, which allows you to set
up additional functions.
Turning the Power On and Off
Turning the Power On – Initial Use
When you turn on the power to the Fishfinder for the first time, the unit
will ask you for some set-up information. This only happens once.
The unit will present a list of languages. The displays and set-up
information for the unit will be presented in the language you choose.
Here are the choices:
English (U.S.A.)
Espanol
Deutsch
Svenska
English (U.K.)
Francais
Italiano
Norska
The units used to measure temperature, depth and speed also depend
on the language. See the table below. (The default setting is “U.S.A.”)
Option
Temp. Units
Depth Units
Speed Units
U.S.A.
°F
feet
miles per hour
English (U.K.)
°C
feet
miles per hour
Other European
languages
°C
meters
kilometers per hour
Chapter 3: Operating Instructions
31
To make a choice, move through the list using the up- and down-controls
on the Trackpad. (This is the large circular control near the lower right
corner of the unit.) When the language you want is highlighted, press
the small Enter button at the bottom of the unit.
You can change the language or the measuring units later, using the
System Setup menu.
Once you do this initial set-up, the unit will not ask you for this information
again. The next section describes the routine start-up.
Turning the Power On - Routine Operation
Press the Power button once to turn on the power. The display will flash
on and off several times. This is normal, and serves as a reminder to
adjust the Lamp and Contrast settings:
Lamp
This sets the brightness of the lamp which provides “backlighting” for the
display area. The same setting also controls the brightness of the lighting
used for the keys. You can increase or decrease the brightness by pressing
the Soft Key labeled Lamp, then using the up- and down-controls on the
Trackpad. Remember to press the Enter key to save the new setting, or the
Clear key to restore the previously saved value. Pressing the Lamp key
several times will toggle the lamp between full on and off. It is not necessary
to use the Trackpad to do this.
Contrast
This entry controls the difference in brightness between the lightest and
darkest parts of the display area. Again, you can increase or decrease the
contrast by pressing the Soft Key labeled Contrast, then using the up- and
down-controls on the Trackpad. Again, press the Enter key to save the new
setting, or the Clear key to restore the previously saved value.
By choosing the extreme settings, it may be possible to make the
display area completely light or completely dark, so that it cannot be
read. If this happens, you can reset the whole unit to the factory default
settings. Turn the unit on by pressing the Power button and the Enter
button at the same time.
Turning the Power Off
To turn the power off, press and hold the Power button for more than 3
seconds. The display will say “Powering Off.” Continue to hold the
Power button until the screen is blank, then release the button.
L750 Fishfinder: Installation and Operation Handbook
32
Setup Memory and Master Reset
When you first turn on the power, the unit will be prepared to operate
using a number of preset values. These “default” values are stored in
the unit at the factory. (The default values are listed in Chapter 4.)
This unit has a memory for some of the settings – range, sensitivity,
zoom, and frequency. (We will explain these in a moment.) When you
turn off the power, any changes you make to these settings will be
saved. You can return all of the settings to the factory default values, and
reset the trip log to zero. To reset the unit, turn it on by pressing the
Power button while holding the Enter button.
Operating Pages
This unit has 3 “pages” or normal displays. These can be used to show
different kinds of information. Here is a list of the three basic pages:
Mode
Function
See page
Downlook page
Standard operating mode, good general
coverage of bottom
p. 33
Downlook page combined with digital information,
four different formats
p. 40
Numerical display of depth, speed, distance traveled
and water temperature
p. 41
Window page
Digital page
To select one of the pages, press the Display button, then use one of the
Soft Keys. See Fig. 3-2.
Once you select a page, you can modify the display using one of the
features listed on the Soft Keys at the bottom - Frequency, Zoom,
Bottom Lock and A-Scope. (We will describe these in detail in a
moment.)
On a unit with the optional “Sidelooker” feature, is one more basic page,
for a total of four. For more information, see the section on “Using the
Optional Sidelooker Feature.”
Fig. 3-2 Display Soft Keys
Chapter 3: Operating Instructions
33
Downlook Page
When you first turn on the display unit, the unit automatically switches to
the Downlook page. Figure 3-3 shows a typical display. (The Downlook
page is also called the “standard” or “chart” or “bottom graph” display.)
As time passes, this display scrolls from right to left. The scrolling image
becomes a record of the echoes and the bottom seen by the Fishfinder
as your boat moves.
The images at the right side of the display show the most recent echoes.
Some of these echoes indicate fish, and others show the bottom. As
new echoes are received, the Fishfinder “draws” a graph of the bottom.
The bottom graph helps you to tell whether the bottom is rising or falling.
It also allows you to identify the shape or “structure” of the bottom. This
can indicate a reef or shipwreck.
4 - Auto zoom on
3 - Auto range on
2 - Auto gain on
5Alarm indicators
6Transducer
frequency
7Boat
symbol
8Water
surface
1Auto
features on
10 - Speed
9Depth
markers
11 Log/
distance
12 Water
temperature
13 Fish
arch
14 Bottom
indication
17 Bottom
depth
15 Range
16 Soft keys
Fig. 3-3 Downlook Page
L750 Fishfinder: Installation and Operation Handbook
34
Notice that the scrolling speed of the display does not necessarily match
the speed of the boat. The scrolling speed of the display is called the
“chart speed.” You can adjust this by pressing the Menu button. (See
Section 4.)
Many of the items on this display appear in the other modes. Since you
are likely to use the Standard page most often, we will explain all of these
items here.
Top of display
1 - Auto features on (AUTO)
If any of the automatic features are turned on, the “Auto” indication
will appear here. (These include the automatic range, auto
sensitivity, and auto zoom features.)
2 - Auto gain on (G)
The “gain” or “sensitivity” controls the ability of the unit to tell the
difference between echoes of different strengths. A higher gain or
sensitivity setting makes it easier to see smaller fish, but also may
pick up background noise. When auto gain or sensitivity is on, the
Fishfinder chooses the correct sensitivity setting automatically.
3 - Auto range on (R)
The “range” is the maximum depth the unit is set to measure.
When the auto range feature is on, the Fishfinder chooses the
correct range setting automatically.
4 - Auto zoom on (Z)
The “zoom” can be used to magnify the image from a small section
of the water below the boat. (This is used with the Zoom feature,
which we will describe in a moment.) When the auto zoom feature
is on, the Fishfinder automatically moves the zoom window up or
down to track the bottom.
5 - Alarm indicators
The Fishfinder has alarms which can be set to sound when the unit
detects a depth less than a pre-set limit (“S” symbol - shallow
alarm), or greater than a pre-set limit (“D” symbol - deep alarm).
Another alarm can be set to sound when the unit sees a fish
(indicated by the fish symbol.) The “S” and “D” symbols flash
whenever the shallow or deep alarm is triggered.
Chapter 3: Operating Instructions
35
6 - Transducer frequency
The transducer can use two frequencies - 50 kHz for wide
coverage, or 200 kHz for a detailed view. You can also set the unit
to use both frequencies at the same time (“dual frequency”). (For
more on this, see “Choosing the Frequency.”)
7 - Boat symbol
This symbol is always turned on. It indicates that the new
information appears at the right edge of the display, and the older
information moves toward the left.
Center of display
8 - Water surface
This symbol (“0”) shows the depth indicated by the top of the
display. Usually, this is the level of the surface of the water. The
depth is shown using the same units as the rest of the display. This
could be feet (FT), fathoms (FA), or meters (M), depending on the
setting you make in the System Setup display. (If the Zoom feature
is turned on, this symbol shows the depth of the top of the zoom
area. If the Bottom Lock feature is turned on, the symbol shows the
depth of the top of the viewing area.)
9 - Depth markers
These markers show depths between the surface and the full depth
range. In this example, the unit is set for a depth range of 100 feet.
This means that each of the depth markers shows an interval of 25
feet.
10 - Speed
This entry shows the speed of the boat through the water. From the
System Setup display, you can turn this item off or change the units
used for this display.
11 - Log/distance
This shows the distance traveled since the unit was turned on, or since
the log was last reset. By pressing the Menu button, you can use the
System Setup Soft Key to turn this item off or change the units used for
this display. You can also use the Log Reset soft key to reset to zero.
12 - Water temperature
This entry shows the current water temperature at the surface of
the water. (The reading for water temperature can be helpful for
L750 Fishfinder: Installation and Operation Handbook
36
finding fish. A particular type of fish will often prefer water in a
narrow temperature range.) From the System Setup display, you
can turn this item off or change the units used for this display.
13 - Fish arch or fish symbol
These markers indicate that the Fishfinder sees a fish. Generally,
the larger the fish arch or fish symbol appears, the larger the fish.
(The size of the fish symbol actually depends on a number of
factors. See the section on “Fish Indications.”)
If the fish is detected using the narrow 200 kHz beam, the display
will show a filled-in symbol. If the fish is detected by the wide 50
kHz beam, the display will use a hollow symbol. (For more on this,
see “Choosing the Frequency.”)
If the fish symbol feature is turned on, a number indicates the depth
of the fish shown by each fish symbol. This number will be shown
using the same depth units (feet, fathoms, or meters) you have
selected on the System Setup display. The fish depth indicator is
turned off when the fish symbol function is off.
Bottom of display
14 - Bottom indication
This shows the bottom of the lake or sea. You can compare this to
the range depth shown in the lower right-hand corner. (In this
example, the darker part of the display shows the unit is getting a
strong echo return from this section of the bottom. The lighter part
of the display represents a weaker return.
15 - Range
The “range” is the maximum depth the unit is set to measure. In
this example, this is 100 feet. You can set the range manually, or
the Fishfinder can do it automatically.
16 - Soft Keys
These can be used to call up different displays or change the set-up
of the unit.
17 - Bottom depth
This indicates the depth of the bottom directly under the boat. You
can select FT (feet), FA (fathoms), or M (meters) using the System
Setup display. If the Fishfinder can’t tell how deep the water is, the
last known depth flashes on the display. This will continue until the
unit can see the bottom again.
Chapter 3: Operating Instructions
37
Before we explain the other basic pages, there are some general things
you should know about the operation of the Fishfinder.
Fish Indications
Even using advanced sonar technology, it is sometimes hard to detect a
fish in the water. The body of a fish is just a little more dense than the
surrounding water. There is really nothing very solid for the sound
waves to bounce off of. The L750 Fishfinder is very good at telling the
difference between a fish and the surrounding water.
When the Fishfinder finds a fish, it displays an arch-shaped mark. See Fig.
3-4. In general, a larger arch indicates a larger fish. This rule is not always
true, though. Let’s say that there are two fish of the same size: one is close
to the surface, and the other is near the bottom. The fish which is close to
An arch-shaped image indicates a fish.
The same fish appears differently
when shown by the 50 kHz or 200 kHz
transducer beams.
50 kHz
200 kHz
This is how the images appear when
the "fish symbol" feature is turned on.
Notice that the depth is indicated.
50 kHz
200 kHz
A shallow arch is generated when
the boat is moving slowly.
This indicates a group of small fish.
This shows a fish detected in
sidelooker mode.
A fish moving under a stopped
boat shows as a line.
When the boat is moving very fast,
a fish appears as two parallel lines.
Fig. 3-4 Fish Indications
L750 Fishfinder: Installation and Operation Handbook
38
the surface will have a larger arch. This is because the fish which is closer
returns more of the sound waves back to the Fishfinder.
Actually, the sound waves are usually reflected by the air sac near the
center of the fish, and not by the body of the fish. The size of this air sac
is different for different kinds of fish. This can also affect the size of the
fish arches on the display. A fish with a large air sac will produce a large
fish arch, while a fish with a small sac will produce a small arch. Several
arches together show a school of fish.
The return from a fish will have a different appearance, depending on the
frequency used. If a fish is spotted by the wide 50 kHZ beam, the arch
will be broad. When using the narrower 200 kHz beam, the same fish
will produce a narrower arch.
The shape of the arch is also affected by the speed of the boat. If the
boat is moving slowly, the arches tend to be longer. If the boat is moving
more quickly, the arches are short and peaked. If the boat is moving
very fast, a fish may be indicated by a single vertical line.
When the Fish Symbol feature is turned on a fish will be indicated by a
fish-shaped symbol on the display. In general, a larger symbol means a
larger fish.
The symbol also indicates which of the two frequencies was used to
locate the fish. If the fish was spotted by the wide 50 kHz beam, the
symbol will appear to be hollow. If the fish was detected by the narrow
200 kHz beam, the symbol will be solid.
Bottom Indications
The bottom usually produces a strong echo, so it is easy for the
Fishfinder to see a lot of detail. The Fishfinder can indicate many
different kinds of bottom conditions. See Fig. 3-5. A hard bottom
appears as a thin line. An uneven bottom which is covered with rocks or
coral produces a complex display like that shown in Fig. 3-5c. The
bottom image is irregular, with long “tails” pointing upward. A wreck
produces a similar image.
A softer bottom or a bottom covered with seaweed will produce a wide line,
as the sound waves reflect from different layers of the bottom. In Fig. 3-5b,
the Fishfinder is getting a good echo from the bottom, so the upper layer of
the bottom is shown as a dark gray area. Notice that the lower layer of the
bottom is shown as a lighter gray area. This indicates a weaker echo.
Sometimes this means that the upper layer of the bottom is soft. Some of
Chapter 3: Operating Instructions
39
the sound waves may reach through this layer, and may be reflected by a
more solid layer below. It is also possible that the sound waves are making
two complete trips – hitting the bottom, bouncing off of the bottom of the
boat, then reflecting off the bottom again. This can happen if the water is
shallow, the bottom is hard, or the sensitivity is set to a high value.
When the White Line feature is turned on, the unit produces a white area
at the top of the dark gray area. The edge of the white area is marked
with a dark line. This feature helps to show the difference between the
bottom itself and any fish which are very near the bottom.
Hard bottom
(sand)
Soft bottom
(mud)
A
B
Rocky bottom
White line feature on:
C
D
Fig. 3-5 Bottom Conditions
Now, let’s look at the other main operating pages. Press the Display
button. On the Soft Keys at the bottom of the display, press the button
for Window.
Window Page
The Soft Key for Window allows access to several different displays.
The right side of each display includes a section of the standard
Downlooker display. The left part of each display includes some digital
information. By choosing one of the three options - A, B, or C - you can
select the digital information you want to display. (Option D is available
if the optional Sidelooker is turned on.) Figure 3-6 shows one of the
options. (To select one of the other options, press the Soft Key under
Window until you see the display you want.)
L750 Fishfinder: Installation and Operation Handbook
40
Here are the items which may be selected for the left half of the display:
Option A
Depth, speed, battery, temperature graph
Option B
Depth, speed, log, temperature graph
Option C
Depth, speed, log, temperature, battery
Option D
Downlooker display with Sidelooker display
Depth
This is the depth of the bottom directly below the boat.
Speed
This item lists the speed of the boat through the water.
Battery
This entry shows the DC voltage of the battery or power source
which is powering the Fishfinder.
Temperature Graph
This item is a graph showing the changes in water temperature
over time.
Part of
downlooker
page
Fig. 3-6
Window “A” Page
Chapter 3: Operating Instructions
41
Log
This entry shows the distance traveled, determined by the speed
through the water. The L750 remembers this value after it is turned
off. You may reset the log by pressing Menu and using the Log
Reset Soft Key.
Let’s move on to the next display page. Press the Display button. On
the Soft Keys at the bottom of the display, press the button for Digital.
Digital Page
The Digital page presents some useful information in large numbers on
the display. See Fig. 3-7. This display is useful when you are traveling,
but not looking for fish or checking the appearance of the bottom.
Here are the items on this page:
Depth
The Digital display reports the depth of the bottom.
Battery
This entry shows the DC voltage of the battery or power source
which is powering the Fishfinder.
Fig. 3-7 Digital Page
L750 Fishfinder: Installation and Operation Handbook
42
Speed
This is the speed of the boat through the water.
Log
This entry shows the distance traveled, determined by the speed
through the water. The L750 remembers this value after it is turned
off. You may reset the log by pressing the Soft Key for Menu and
using the Log Reset Soft Key.
Elapsed Time
This item shows the amount of time which has passed since the
unit was turned on. You may reset the time by pressing Menu and
using the Soft Key for Elapsed Time Reset.
Current Water Temperature
The display indicates the current water temperature.
Water Temperature Graph
One version of the display presents a graph showing the changes
in water temperature over the previous 100 minutes.
Modifying Displays
The Downlook and Window pages can be modified by using the Soft
Keys which appear across the bottom of the display area. These Soft
Keys control the Frequency, Zoom, Bottom Lock and A-Scope features.
Frequency Soft Key
We said that the Fishfinder uses sound waves to “see” through the water
under the boat. The “frequency” is a measure of how fast the sound
waves change or “vibrate.” The Fishfinder uses sound waves with two
different frequencies – 50 kHz and 200 kHz. Raymarine uses these two
frequencies because each is better for a particular purpose. When you
press the Soft Key for Frequency, the unit presents four more Soft Keys.
See Fig. 3-8.
Fig. 3-8
Frequency Soft Keys
Chapter 3: Operating Instructions
43
50 kHz frequency
When using this frequency, the transducer can scan a wide area.
The 50 kHz signal penetrates water well, so it is good for use in
deep water.
200 kHz frequency
When using this frequency, the transducer scans a narrower area,
but produces a more detailed view. The 200 kHz frequency is good
for seeing fish which are near the bottom or are close together. The
200 kHz setting is better for use in very shallow water.
“Dual” frequency
These settings use both the 50 kHz and 200 kHz signals at the
same time. This allows for some of the advantages of both
frequencies. The dual settings produce good depth penetration
and good detail in the display. Using the “Dual 50 kHz” setting, the
display is produced using the signal from the 50 kHz beam, with
additional information from the 200 kHz beam. Using the “Dual 200
kHz” setting, the display is produced using the signal from the 200
kHz beam, with additional information from the 50 kHz beam.
Display
from 200 kHz
beam
Display
from 50 kHz
beam
Fig. 3-9 Split Frequency Feature
L750 Fishfinder: Installation and Operation Handbook
44
If you are using one of the dual frequency settings, you can get
some useful information from the fish symbols. If the fish is spotted
by the narrow 200 kHz beam, the fish symbol will be black or filledin. If a fish is detected by the wide 50 kHz beam, the symbol will be
hollow.
“Split” screen display
The Split display presents two separate images at the same time one from each of the transducers. The upper half of the display
shows the image from the 200 kHz transducer, and the lower half
shows the image from the 50 kHz transducer. See Fig. 3-9.
Remember, you can use these settings to modify the Downlooker,
Bottom Lock, or A-Scope displays. For example, you could set up a split
screen display using the A-Scope feature.
To change the frequency setting, press the Soft Key for Frequency at the
bottom of the display, then press the correct Soft Key to make your
choice. (The Soft Key for “Dual” has two choices. Press the Soft Key
until the choice you want is highlighted.)
Zoom Soft Key
The Zoom feature gives you a way of enlarging or magnifying a part of
the display area. Figure 3-10 shows the standard Downlook display with
the Zoom feature turned on. The right side of the display shows the
same information as the Downlook page. The left side shows the
zoomed or magnified view. (The “zoomed” display is actually larger only
in the vertical direction.) In each part of the display, the new information
appears at the right edge of the display, and moves to the left.
Many of the items on the Zoom page are the same as those on the
Standard page. There are a few new items:
Zoom magnification
This indicates the amount of “zoom” or magnification. You can set
the amount of zoom manually, using one of the Soft Keys which
appear when you press the Zoom Soft Key. See Fig. 3-11. You
can choose an x2 view (double the normal display size), x4, x6 or
x8. You must also select the area or “window” of the water you
want to zoom. See the next item.
Chapter 3: Operating Instructions
45
Zoomed area
Part of downlooker page
Auto zoom is on
Depth
at top
of zoom
area
Zoom
area
selector
bar
Zoom
magnification
Depth
at bottom
of zoom
area
Fig. 3-10 Zoom Feature On
Zoom area
When you turn on the zoom feature, it can only enlarge a part of the
Downlook display. You must decide which part you want to enlarge.
As we said, the right side of the display shows the normal Downlook
display. The vertical line at the right edge of this display shows the
area or “window” of the water being enlarged. On the right edge of the
zoomed section of the display, the number at the top of the display
shows the depth at the top of the zoomed area. The number at the
bottom shows the depth at the bottom of the zoomed area.
When the Fishfinder is set for Auto Zoom, it will choose the zoom area
automatically. The unit always chooses an area of the water which
includes the bottom. The unit then moves this area up or down to keep
the bottom in the picture. The Auto Zoom feature is helpful for bottom
fishing.
L750 Fishfinder: Installation and Operation Handbook
46
You may also set the zoom area manually. When you first press
the Zoom Soft Key, another set of Soft Keys appear at the bottom
of the display. See Fig. 3-11. Use one of these to select Manual
Zoom. Once you have done this, you can move the zoom area up
or down using the up- and down-controls on the Trackpad.
The Zoom feature may be used with the Downlook or the Window
displays.
Fig. 3-11 Zoom Soft Keys
Figure 3-11 shows the four Soft Keys which appear when you press the
Zoom Soft Key:
Zoom On/Off
Use this Soft Key to turn the Zoom feature on or off. If you are
looking at the standard Downlook display, you press the Zoom Soft
Key, and then press the Soft Key for Zoom On, the Zoom display
will be added to the Downlook display. See Fig. 3-10. The other
Zoom Soft Keys will not work unless the Zoom feature is turned on
first.
Zoom Full/Split
Once the Zoom feature is turned on, the Zoom image can share the
display as shown in Fig. 3-10. The Zoom image can also occupy all
of the display area. You can make this selection using the Zoom
Full/Split Soft Key.
Zoom Auto/Manual
The unit must know how to set the zoom area. This sets the area or
“window” of the water being enlarged by the Zoom function. (For
an explanation of the Zoom area, see the beginning of this section.)
Zoom x2468
This Soft Key allows you to set the Zoom magnification. Press the
Soft Key until the magnification you want is highlighted.
Chapter 3: Operating Instructions
47
Bottom Lock Soft Key
The normal display on the Fishfinder is a “top-down” view, as if it was seen
from the surface of the water. When the Bottom Lock feature is turned on,
the unit shows a “bottom-up” view. The bottom is used as the reference,
and echoes from objects directly above the bottom are displayed. See Fig.
3-12. This feature is helpful when searching for types of fish which feed
close to the bottom.
Part of
downlooker
page
Bottom
lock
image
Top of
bottom
lock
range
Bottom
lock
area
Fig. 3-12 Bottom Lock Display
Here are the special items on this display:
Bottom Lock Image
Figure 3-12 shows a display which has been modified using the
Bottom Lock feature. The right side of the display shows part of the
familiar Downlook image. The left side shows the Bottom Lock
image. The bottom is indicated as a straight line. The actual
bottom is not flat like this, of course. The straight line represents the
part of the bottom which is actually under the boat at the moment.
The depth of the bottom represented by the line will change from
moment to moment, as the shape of the bottom changes. The
Bottom Depth reading shows the current depth represented by the
line. Notice that some of the bottom features may extend above
this line.
L750 Fishfinder: Installation and Operation Handbook
48
Range
When the Bottom Lock feature is turned on, the range is measured
up from the bottom, rather than down from the surface. The
number at the top of the display area shows the maximum distance
above the bottom the unit is prepared to monitor. The range setting
for the Bottom Lock feature can be changed using one of the Soft
Keys which appears when you press the Bottom Lock Soft Key.
See the next section.
You can use the Bottom Lock feature to modify the Downlook and
Window displays.
When you press the Bottom Lock Soft Key, three new Soft Keys appear
at the bottom of the display:
Bottom Lock On/Off
Use this Soft Key to turn the Bottom Lock feature on or off. When
you do this, the unit will say “Initializing Bottom Lock” for a moment.
Bottom Lock Full/Split
Once the Bottom Lock feature is turned on, the Bottom Lock image
can share the display as shown in Fig. 3-12. The Bottom Lock
image can also occupy all of the display area.
Bottom Lock Range
When the Bottom Lock feature is turned on, the unit uses a special
range setting. Press the Soft Key for Bottom Lock Range once to
highlight the range setting. Next, use the up- and down- controls on
the Trackpad to set the Bottom Lock Range. (Do not use the
Range button for this.)
Fig. 3-13 Bottom Lock Soft Keys
Chapter 3: Operating Instructions
49
A-Scope (Bottom Coverage) Key
On the Downlook display, the bottom graph is “drawn” after the
Fishfinder receives several echoes. This has the effect of showing a
record of the bottom contour. The A-scope displays raw sonar data
directly from the transducer beam. This gives you a “real time” image of
fish and bottom structure directly below the transducer. This function is
very useful in showing the strength of the echo returned from a fish.
Stronger fish echoes on the A-scope display will appear wider. Weaker
echoes appear as narrow bands closer to the horizontal center of the Ascope image.
Figure 3-14 shows a sample of the A-Scope display. The left section of
the A-Scope display shows a section of the Downlook display. All of the
features are the same. The right section shows the A-Scope image.
A-Scope image
This shows the beam of sound waves extending down from the
boat, and spreading as it moves through the water. Any fish or
objects which are positioned under the boat will appear on the
A-scope
image
Part of
downlook
page
Fish
image
Bottom
coverage
Fig. 3-14 Downlook Page with A-Scope
L750 Fishfinder: Installation and Operation Handbook
50
display. This is a “real time” display, so you can see the fish images
moving as the fish swim under the boat.
Bottom coverage
This shows the diameter of the beam of sound waves where it
meets the bottom. This dimension will be shown using the same
units as the rest of the display – feet (FT), fathoms (FA), or meters
(M). If the unit is set at 200kHz single frequency, the bottom
coverage display will reflect the narrow (16°) beam of the 200kHz
frequency setting. All other frequency selections (200kHz dual,
50kHz dual, and 50kHz single) use the wider (65°) beam for the
bottom coverage display.
You can use the A-Scope feature to modify the Downlook and Window
displays.
Other Control Buttons
The unit includes a number of other control buttons which we have not
detailed yet. Each of these is dedicated to one particular function.
Display
You can use the Display button to call up the three main “pages” or
displays. Figure 3-2 showed the Soft Keys which appear when you
press Display. We explained the choices earlier in this manual:
Downlook page
Standard display
Page 33
Window page
Standard display with digital info.
Page 40
Digital page
Digital info. only
Page 41
Note – If the optional Sidelooker feature is turned on, a fourth Soft Key
will allow you to choose the Sidelooker page.
Gain/ Sensitivity
The “Gain” or “Sensitivity” setting controls the ability of the unit to tell the
difference between echoes of different strengths. In general, the
sensitivity should be as high as possible, to detect the fish and show the
detail on the bottom. However, if the sensitivity is too high, the unit will
begin to see bubbles in the water, debris, and other “background noise.”
Use a higher sensitivity setting for deeper water, and a lower setting for
shallower water.
Chapter 3: Operating Instructions
51
To change the gain or sensitivity setting, press the Gain button. Four
new Soft Keys may appear at the bottom of the display, depending on
the frequency selected at the moment. See Fig. 3-15.
As we explained, the unit can use sound waves with two different
frequencies – 50 kHz and 200 kHz. Each frequency is better for a
particular purpose. The 50 kHz frequency scans a wide area. Because
it penetrates water well, 50 kHz is good for deep water. The 200 kHz
frequency scans a narrower area, but produces a more detailed view.
This frequency is good for seeing fish near the bottom or close together.
Notice that the settings you make here do not control which frequency is
used to generate the display. (You do that by pressing the Menu button,
then using the Soft Key for Frequency.) The Gain controls set up the
sensitivity for each transducer. You can decide later whether to use one
transducer or both to generate the display.
Gain Auto/Manual
When you choose the Auto setting, the Fishfinder will select the
gain or sensitivity by itself, automatically. When using the Auto
setting, the unit chooses the best sensitivity which will detect fish,
but will also show a minimum of background noise. If the amount of
background noise changes (due to changing depth or water
conditions), the Fishfinder will change the sensitivity to adjust.
You can also set the sensitivity manually. If you choose the Manual
setting and the amount of background noise changes, the
Fishfinder will not adjust for this. (To adjust the sensitivity manually,
use one of the next two Soft Keys.)
Even if you choose the Auto setting, you can fine-tune the gain
setting. Go to the Soft Key for the 50kHz or 200 kHz setting, and
adjust the gain as you would normally. (See the information on the
next two soft keys.) When the Fishfinder is turned off, then on
again, the Auto sensitivity setting will return to the normal or default
setting. Also, toggling between Auto and Manual will return the
Auto sensitivity setting to the default value.
50 kHz Setting
To make the gain or sensitivity setting when the unit is using the 50
kHz frequency, press this Soft Key. You will notice that the 50 kHz
frequency number is highlighted. Use the up- and down- controls
on the Trackpad to adjust the sensitivity. Making the dark bar
longer increases the sensitivity.
L750 Fishfinder: Installation and Operation Handbook
52
200 kHz Setting
To make the gain or sensitivity setting when the unit is using the
200 kHz frequency, press this Soft Key. Use the up- and downcontrols on the Trackpad to adjust the sensitivity.
Note – If the optional Sidelooker feature is turned on, there is an extra
Soft Key which allows you to set the gain/sensitivity for the Sidelooker.
See Section 4.
Fig. 3-15 Gain or Sensitivity Soft Keys
Range
The “Range” is the maximum depth that the unit will display. To adjust
the range setting, press either the top or the bottom of the Range button.
Figure 3-16 shows the Soft Keys which allow you to set the range.
Range Auto/Manual
When you first press the Range button, the Fishfinder asks you to
set the range manually. Use the upper or lower parts of the Range
button to decrease or increase the range. If the bottom rises or falls
when Manual Range is selected, the Fishfinder will not adjust for
this.
The Fishfinder can also be set to select the range by itself,
automatically. Use the Soft Key to select the Auto Range function.
The unit chooses the shallowest range which will still include the
bottom in the display. To go back to Manual Range, use the Soft
Key to make the selection, or press either side of the Range button.
Range Downlook
If you select Manual Range or press this Soft Key, the Fishfinder
allows you to choose the manual range setting you want. The
current range setting will be highlighted. To change the setting, use
the up- or down-controls on the Range button.
Chapter 3: Operating Instructions
53
Here is a list of the possible range settings
In feet:
5, 10, 15, 20, 30, 40, 50, 60, 80, 100, 150, 180, 200,
250, 300, 400, 600, 800, 1000, 1500, 2000, 2500
In fathoms:
1, 2, 3, 4, 5, 8, 10, 15, 20, 25, 30, 40, 50, 60, 80, 100,
150, 200, 250, 300, 450
In meters:
2, 4, 6, 8, 10, 15, 20, 25, 30, 40, 50, 60, 80, 100, 150,
200, 300, 400, 500, 600, 800
Note – If the Sidelooker feature is turned on, there is an extra Soft Key
which allows you to set the range for the Sidelooker. See Section 4.
Fig. 3-16 Range Soft Keys
VRM depth
VRM marker
Fig. 3-17 Variable Range Marker
VRM
“VRM” means “Variable Range Marker.” On this unit, the VRM feature
offers a way of finding the depth of an object on the display. To use the
feature, press the VRM button to create a horizontal line on the display.
L750 Fishfinder: Installation and Operation Handbook
54
See Fig. 3-17. Using the up- and down-controls on the Trackpad, you
can move this line up or down to match the depth of the object you are
checking. The entry for “VRM Depth” will change to indicate the depth
shown by the VRM line. The VRM will not operate if any Soft Keys other
than the four default keys are displayed.
Multi-purpose
This button allows you to adjust the contrast and backlighting level used
for the display. These are the same controls which appear when you
first turn the unit on. By using the Multi-purpose button, you can reach
these controls at any time. When you press the Multi button, the unit
presents the two Soft Keys shown in Fig. 3-18.
Lamp
This sets the brightness of the lamp which provides “backlighting”
for the display area. The same setting also controls the brightness
of the lighting used for the keys. You can increase or decrease the
brightness by pressing the Soft Key then using the up- and downcontrols on the Trackpad. Pressing the Lamp key several times will
toggle the lamp between full on and off. It is not necessary to use
the Trackpad to do this.
Contrast
This entry controls the difference in brightness between the lightest
and darkest parts of the display area. Again, you can increase or
decrease the contrast by pressing the Soft Key, then using the upand down-controls on the Trackpad.
By choosing the extreme settings, it is possible to make the display
area completely light or completely dark, so that it cannot be read.
If this happens, you can reset the whole unit to the factory default
settings. Turn the unit on by pressing the Power button and the
Enter button at the same time.
Fig. 3-18 Multi-Purpose Soft Keys
Chapter 3: Operating Instructions
55
Alarms
The Fishfinder has two kinds of depth alarms, and an alarm which is
triggered when fish are present. The Alarm button allows you to set
these alarms. When you press the Alarm button, the unit will present the
four Soft Keys shown in Fig. 3-19.
Fig. 3-19 Alarm Soft Keys
Shallow Alarm
The first Soft Key controls the set-up for the Shallow Alarm. You can set
an alarm to trigger whenever the boat moves into water which is
shallower than a limit you set. When you press the Soft Key, the current
limit will be highlighted. The limit depth will be shown in feet, fathoms or
meters - the same depth units used in the other displays. To change the
limit, use the up- and down-controls on the Trackpad. If the limit for
Shallow Alarm is set to “0” the feature will be turned off.
When the shallow alarm is set, the letter “S” will appear in the upper lefthand corner of the normal displays. If you move into shallow water and
trigger the alarm, the letter “S” will begin to flash, and the buzzer will
sound. Press the Clear button to silence the buzzer. The letter “S” will
continue to flash until you move into deeper water.
Deep Alarm
Another Soft Key controls the set-up for the Deep Alarm. This allows you to
set an alarm to trigger whenever the boat moves into water which is deeper
than a limit you set. When you press the second Soft Key, the current limit
will be highlighted. The limit depth will be shown in feet, fathoms or meters the same depth units used in the other displays. To change the limit, use
the up- and down-controls on the Trackpad. If the limit for Deep Alarm is set
to the maximum limit, the feature will be turned off.
When the deep alarm is set, the letter “D” will appear in the upper lefthand corner of the normal displays. If you move into deep water and
L750 Fishfinder: Installation and Operation Handbook
56
trigger the alarm, the letter “D” will begin to flash, and the buzzer will
sound. Press the Clear button to silence the buzzer. The letter “D” will
continue to flash until you move into shallower water.
Note: You may want to use both the Shallow Alarm and Deep Alarm
features when you are anchored. Set the limits just a bit to either side of
your anchor depth. When set this way, the unit will trigger an alarm if the
anchor drags and the boat moves into shallower or deeper water.
Fish Alarm
The third Soft Key controls the Fish Alarm feature. This alarm will trigger
when the unit detects a fish. Press the Soft Key again to turn this item on
or off. The fish alarm feature will work even if the fish symbols are turned
off.
When the fish alarm is set, the fish symbol will appear in the upper lefthand corner of the normal displays. If a fish is detected, the buzzer will
sound. The unit uses different buzzer tones to indicate fish detected by
the 50 kHz and 200 kHz transducers.
Buzzer
The fourth Soft key sets up the Buzzer feature. Press the Soft Key
several times to see the three possible settings. If you choose the
setting labeled Alarms, the buzzer will sound when any of the alarm
conditions occurs (shallow, deep, or fish alarm). When one of the
alarms is tripped, the “S” or “D” symbol at the top of the screen will flash.
By pressing the Clear button, you can silence the buzzer for the current
alarm condition. The “S”or “D” symbol will continue to flash as long as
the alarm condition is still present.
If the alarm condition occurs again, the buzzer will sound again. (For
example, this would happen if, after a shallow alarm you moved into
deep water, then returned to shallow water.) You can silence the buzzer
again by pressing the Clear button.
If you choose the setting for Alarms + Keys, the buzzer will also sound a
short “beep” each time you press one of the buttons on the control panel.
This confirms that you have pressed the button hard enough, and that
the unit has received your command.
Chapter 3: Operating Instructions
57
When the Buzzer entry is set to Off, the buzzer is silenced for all of the
alarms. Once you choose this option, if a shallow alarm, deep alarm or
fish alarm occurs, the “S” or “D” symbol will flash, but the buzzer will not
sound. (You can enable the buzzer again at any time by pressing the
Alarm button, then the Buzzer Soft Key, and turning the item on again.)
Mark
The Mark button allows you to set a vertical marker on the display over a
selected point on the bottom. See Fig. 3-20. As the display scrolls past,
the vertical line keeps the same position relative to that point on the
bottom. The distance measurement shows how far you have traveled
since you set the mark. The distance will continue to increase until the
line leaves the left edge of the display, or until you press the Mark button
again.
The calculation for the Mark line is based on the information used for the
Log/distance display. If you reset the log, the Mark function will be reset
also.
Mark line
Mark distance
Fig. 3-20 Mark Display
L750 Fishfinder: Installation and Operation Handbook
58
About the Sidelooker Feature
Some installations include the optional “Sidelooker” transducer. The
Sidelooker feature is very helpful for certain kinds of fishing. The
transducer used with the Sidelooker transmits two beams. The two sides
of the Sidelooker page represent the port and starboard Sidelooker
beams. See Fig. 3-21. The Sidelooker feature allows you to check along
the sides of a stream or river. You can also look under the edge of a
bank or pier, or into a snag or shallow spot.
The Sidelooker information will not be displayed unless the Sidelooker
feature is turned on. To do this, go to the System Setup menu. Press
the Menu button, then choose the Soft Key for System Setup. Using the
up- and down-controls on the Trackpad, go to the line labeled Sidelook.
Use the left- and right-controls to turn the feature on and off.
Once the Sidelooker feature has been enabled, the unit can present an
additional display. See Fig. 3-22. When you press the Display button, a
fourth Soft Key allows access to the Sidelooker page
Rock
31° beam
Fish
Boat
Rock
Fish
Sidelooker
transducer
11° beam aimed
down at 4° angle
Fig. 3-21 Sidelooker Feature
Chapter 3: Operating Instructions
59
Centerline
Bottom or
river bank
echoes
Fish
image
Depth
below
boat
Fig. 3-22 Sidelooker Page
The Sidelooker Page
The Sidelooker page, like the Standard page, displays a graph or chart.
As new echoes are received by the Sidelooker transducer, the chart
scrolls from the top to the bottom of the display. The display is divided by
a boat symbol and centerline indicator. The line at the center of the
display represents the centerline of the boat. The new information
appears at the top of the display. Older information moves towards the
bottom. The display scrolls from top to bottom, but this does not
necessarily happen at the same speed the boat is moving. (The speed
at which the display moves is set by the Soft Key for Chart Speed. To
reach this Soft Key, press the Menu button.)
The Sidelooker transducer transmits at the 200kHz frequency. The unit
presents different kinds of information, depending on whether the “fish
symbol” feature is turned on or off.
If the fish symbols are turned off Fish echoes appear as vertical arches. This setting allows the unit to
display underwater objects such as shorelines, river banks, piers,
submerged tree stumps or rocks.
L750 Fishfinder: Installation and Operation Handbook
60
If the fish symbols are turned on Any fish echoes appear as easy-to-read fish symbols, along with the
distances from the boat. When the fish symbol feature is used with the
Sidelooker page, the unit can carefully discriminate between fish and
unwanted echoes. This allows the Fishfinder to accurately locate and
identify only fish.
The Sidelooker sounding beam is transmitted very close to the surface
of the water. In rough or choppy water this turbulence may appear on the
Sidelooker display as “noise” or “clutter.” The Sidelooker will also display
noise or clutter when your boat travels at high speeds. For best results,
use the Sidelooker at idle or slow trolling speeds.
Here are the special items on this display:
Boat symbol
This shows that the bow of the boat is aiming forward, toward the
top of the display.
Centerline
The centerline of the boat is lined up with the centerline of the
display. (If the boat is turning, this only applies to the top of the
display. The centerline does not curve to match your course.)
Side range
This is the maximum distance the unit will be able to see using the
current range setting. Remember that the sound waves move out
at a shallow angle, so this distance is measured sideways. See
Fig. 3-21. The units used here are chosen using the entry for
Depth Units in the System Setup display. If you have selected feet
(FT) or fathoms (FA), the distance shown here will be measured in
feet. If you have selected meters (M), the distance shown here will
be in meters.
Depth
This is the depth directly below the boat. Even when the Sidelooker
feature is turned on, the downward-looking transducer is still used
to measure the depth.
Chapter 3: Operating Instructions
61
The Split-Screen Sidelooker Page
The unit can also display Sidelooker information in a split-screen format.
When you choose the Window “D” display, the Sidelooker information
shares the display with part of the Downlooker display. See Fig. 3-23.
Sidelooker
display
Part of
downlooker
page
Fig. 3-23 Window “D” Page with Sidelooker Information
Turning on the Sidelooker Feature
The Sidelooker feature must be turned on using the System Setup
display. Press the Menu button, then the System Setup Soft Key, to
reach the System Setup display. See Fig. 4-3. Press the down-control
on the Trackpad to reach the line labeled “Sidelook.” Press the leftcontrol to turn the feature on.
This unit uses separate settings for the range and gain/sensitivity for the
Sidelooker feature. You will have access to the Soft Keys for these
functions once the Sidelooker feature has been turned on.
Setting the Sidelooker Range
The unit uses a separate Range setting for the Sidelooker feature. (This
is different from the setting used for the Downlook page.) You must set
the range for the Sidelooker feature manually. (If the bottom rises or falls
when Manual Range is selected, the Fishfinder will not adjust for this.)
L750 Fishfinder: Installation and Operation Handbook
62
If you press either side of the Range button while the Sidelooker display
is showing, the unit will allow you to set the range used for the
Sidelooker. To adjust the range setting, press either the top or the
bottom of the Range button.
Possible Sidelooker Range Settings (Manual only for Sidelooker)
In feet:
5, 10, 15, 20, 30, 40, 50, 60, 80, 100, 150
In fathoms:
The unit will display the Sidelooker range in feet.
In meters:
2, 4, 6, 8, 10, 15, 20, 25, 30, 40, 50
If you are satisfied with your setup changes, press the Enter button to
save the changes and go back to the normal display. If you want to
leave without saving the changes, press Clear.
Setting the Sidelooker Gain/ Sensitivity
The unit also has a separate Gain or Sensitivity setting for the Sidelooker
feature. When the Sidelooker feature is turned on, the Soft Keys for the
sensitivity setting appear when you press the Gain button. The
Fishfinder gives you a choice between the Manual and Auto Gain
settings. Press the Soft Key labeled Gain, and make a selection.
If you select Manual Gain, press the Soft Key labeled Sidelook, and use the
up- and down-controls on the trackpad to change the setting. Making the
dark bar longer increases the sensitivity. If the amount of background noise
changes when Manual Gain is selected (due to changing depth or water
conditions), the Fishfinder will not adjust for this.
The Fishfinder can also be set to select the gain for the Sidelooker
feature by itself, automatically. Use the Soft Key to select the Auto Gain
function. The unit chooses the sensitivity which will detect fish, but will
also show a minimum of background noise. If the amount of
background noise changes, the Fishfinder will change the sensitivity to
adjust.
If Auto Gain is selected, you can fine-tune the setting. Press the Soft
Key labeled Sidelook, and use the up- and down-controls on the
trackpad to change the setting. When the Fishfinder is turned off, then
on again, the Auto sensitivity setting will return to the normal or default
settings. Also, toggling between Auto and Manual will return the Auto
Sensitivity setting to the default value.
If you are satisfied with your setup changes, press the Enter button to
save the changes and go back to the normal display. If you want to
leave without saving the changes, press Clear.
Chapter 4: Setup Instructions
63
Chapter 4: Setup Instructions
The Setup Menus
There are two groups of setup menus. When you press the Menu
button, the unit presents four Soft Keys. See Fig. 4-1. If you make a
change, press the Enter button to save the change and return to the
normal display. To return without making a change, press Clear.
Fig. 4-1 Menu Soft Keys
Chart Speed Setting
Most of the displays on the Fishfinder show a record of the signals the
unit has received. The new information appears at the right edge of the
display. The older information moves toward the left of the display. (If
the Sidelooker screen is displayed, the new information appears at the
top and moves toward the bottom.) The chart speed adjustment sets
the speed at which the display moves. (Notice that the scrolling speed of
the display is not related to the speed of the boat over the bottom. The
speed of the display is controlled only by the chart speed setting.)
Section of bottom shown
at higher chart speed -
Display shows
more detail
Same section shown at
slower chart speed -
Display shows
longer "history"
Fig. 4-2 Changing the Chart Speed Setting
Figure 4-2 shows how the chart speed setting affects the display. In both
cases, the unit is showing the same section of the bottom. Using a faster
L750 Fishfinder: Installation and Operation Handbook
64
chart speed, the display has more space on the display to show this
section, so it can include more detail. Using a slower chart speed, this
same information is displayed in a smaller horizontal space.
A faster chart speed setting shows more detail on the bottom. You will
probably want to use a faster setting when you are looking for fish.
A slower chart speed setting shows a longer record of the bottom you
pass over. Any fish detected will stay on the display longer.
To change the setting, press the Menu button, then select the Soft Key
for Chart Speed setting. Use the up- and down-controls on the Trackpad
to change the setting. Making the bar longer increases the chart speed.
If you move the bar all of the way down, the Fishfinder will “freeze” and
hold the current display. (The depth indicator will continue to update.)
Log Reset
The “log” measures how far the boat has traveled through the water.
The log feature on this unit records the distance traveled since the power
was turned on, or since it was last reset. This number appears in the
upper left corner of the display. On a digital display, the log reading will
be presented as a large number. You can reset the log at any time by
pressing the Menu button, then selecting the Soft Key for Log Reset.
Elapsed Time Reset
This Soft Key is only visible when the unit is in the Digital display mode.
You can reset the elapsed time using this button.
System Setup Menu
If you press the Menu button, selecting the fourth Soft Key will bring you
directly to the System Setup menu. This means that you can reach this
display, make a change, then return to the normal display quickly.
Figure 4-3 shows the items in this display.
To change one of the items, use the up- and down-controls on the
Trackpad to move up or down in the display. This will highlight an area
on the display where the unit is ready to make a change. (This is like the
“cursor” on a computer.)
Once you have moved to the correct line, press the left- or right-controls
on the Trackpad to change the entry. If you want to save the changes,
press the Enter button to leave the menu. If you want to leave without
saving the changes, press the Clear button. (Notice that you must press
one of these buttons to leave the menu. When you choose the System
Setup menu, the unit will not return to the normal display automatically.)
Chapter 4: Setup Instructions
65
Fig. 4-3 System Setup Menu
Here are the items on this menu:
Simulator
This unit has a built-in simulator. When the simulator is enabled, it
presents a realistic display. You can use this display to learn about
the features of the unit without operating your boat. The information
on this display is generated by the unit itself, and does not come
from a transducer. When this mode is turned on, you will see the
word “Simulation” flashing on the display.
Language
When this unit is using the default settings, the display uses the
English language. You may also select French, German, Italian,
Spanish, Norwegian, or Swedish.
Fish symbols
When the unit detects a fish, it can be set to indicate this using a fish
symbol. A number above the symbol shows the depth of the fish.
The size of the symbol is related to the size of the fish. In general,
the larger the symbol, the larger the fish. (For more information,
see the section on “Fish Indications.”)
L750 Fishfinder: Installation and Operation Handbook
66
When the fish symbol is turned off, the unit indicates a fish by
showing an arch-shaped line. See Fig. 3-4. This kind of display
does not include the depth readings for the fish.
White line
This feature controls the way the unit indicates the upper surface of
the bottom structure. When the feature is turned on, the unit
displays a dark line along the upper edge of the bottom image. This
makes it easier to locate any fish which are very near the bottom.
Sidelook
This item is used with the optional “Sidelooker” transducer. This
type of transducer sends sound waves out to the sides of the boat.
See Fig. 3-21. If you have installed a Sidelooker transducer, use
this line of the display to turn on the Sidelooker feature.
Speed Cal
This unit can detect and display the speed of the boat through the
water. It also uses the speed information to calculate the distance
traveled (the “log”). The item for Speed Cal allows you to adjust the
speed reading to make it match your actual speed through the
water. It presents a reading in percentage points. A reading of
100% means the speed readings from the factory default
calibration are accurate, and the unit does not need any correction.
If the unit says that you are moving faster than you really are, you
can adjust the Speed Cal figure to a smaller number. If the unit
says that you are moving slower than your actual speed, use a
larger number for Speed Cal. The setting can range between 75
and 125. Use the left- and right-controls to change the value. For
more information, see the section on “Calibrating the Sensors.”
Temp Cal
This unit can display the water temperature. You may want to finetune the signal from the transducer to get an accurate display. The
displayed number indicates an offset added to the measured
temperature. (This offset will be measured in °F or °C, depending
on the setting used for Temp Units.) For example, if the
temperature reading on the display tends to read 2°F too high, you
can correct for this by setting Temp Cal to -2.0°. The setting can
range between -9.9° and +9.9°. Use the left- and right-controls to
change the value.
Chapter 4: Setup Instructions
67
Depth Digits
This item sets the size of the digits used to show the bottom depth
on the Standard and Dual displays. The “standard” setting
specifies digits which are 9 mm tall, and the “large” setting calls for
digits which are 18 mm tall. Use the left- and right-controls to
change the setting.
Depth Units
This item sets the units used by the depth display. You can choose
feet (FT), fathoms (FA), or meters (M). Use the left- and rightcontrols to change the setting.
Speed Units
This item sets the units used by the speed display. The same units
are used for the distance (“log”) display. There are three choices:
Code
Units used for speed
Units used by log
MPH
Miles per hour
Statute miles
KTS
Knots
Nautical miles
KPH
Kilometers per hour
Kilometers
Use the left- and right-controls to on the Trackpad to change the
setting.
Temp Units
This item sets the units used by the temperature display. You can
choose Fahrenheit degrees (°F) or Celsius degrees (°C). Use the
left- and right-controls to change the setting.
Speed On/Off
A speed indication appears on the Downlooker page. If you do not
want to see this item, you can turn it off using this line of the System
Setup display. Use the left- and right-controls on the Trackpad to
change the setting. (The Speed item will still appear on the Window
and Digital displays.)
Log On/Off
On the Downlooker page, an entry for “log” indicates the distance
traveled. You can turn off this item using this line of the System
Setup display. Use the left- and right-controls on the Trackpad to
change the setting. (The Log entry will still appear on the Window
and Digital displays.) Notice that the units used by the log are set
by changing the entry for Speed Units.
L750 Fishfinder: Installation and Operation Handbook
68
Temp On/Off
An entry for temperature may appear on the Downlooker page.
You can turn this item off using this line of the System Setup
display. Use the left- and right-controls on the Trackpad to change
the setting. (This item will still appear on the Window and Digital
displays.)
Resetting the Unit to Factory Defaults
It is easy to reset all of the settings on the Fishfinder to the original factory
settings. When the unit is off, press and hold the Enter key while
pressing the Power key. The unit will display the message, “EEPROM
initialization. Press the Enter key to exit.” To go back to normal
operation, press the Enter button. All of the settings will be reset to the
values listed below.
Default Settings
When the Fishfinder is new, it uses a number of preset “default” settings.
Here is a list:
Function
Default – US model
Default – European model
Range
Auto
Auto
Sensitivity
Auto
Auto
Chart Speed
3 (fast)
3 (fast)
Zoom
Auto/x2
Auto/x2
Frequency
200 kHz
200 kHz
Simulator
Off
Off
Fish symbols
Off
Off
White line
Off
Off
Sidelooker
Off
Off
Depth units
FT (feet
M (meters)
Temperature unit
°F (Fahrenheit)
°C (Celsius)
Speed units
MPH (miles per hour)
KPH (kilometers per hour)
Shallow alarm
Off
Off
Fish alarm
Off
Off
Deep alarm
Off
Off
Buzzer
Both
Both
Speed/temp/log
On
On
Chapter 5: Maintenance and Troubleshooting
69
Chapter 5: Maintenance and
Troubleshooting
Periodically check the display unit, cable, and transducer. Be sure all
components are free of corrosion and are securely mounted. Check all
cables for signs of chafing or abrasion. Be sure all of the connections to
the boat’s DC power and ground system are clean and tight.
Cleaning Instructions
Always keep the display unit clean. Use a soft, clean cloth to wipe off the
display panel. Do not use abrasive cleansers, chemical cleaners or
solvents. Use a glass cleaner or a suitable general-purpose detergent.
If you operate your boat in salt water, you will have to protect the hull with
antifouling paint. Use caution when sanding or cleaning the outside of
the hull near the transducer. Harsh cleaning solvents such as acetone
may damage the transducer.
Sea growth can collect quickly on the bottom of the transducer. This can
reduce the performance in just a few weeks. To prevent this, coat the
bottom of the transducer with a thin layer of paint. Use only a waterbased antifouling paint, or a water-based paint specifically designed for
transducers. Apply it with a brush.
If your transducer becomes fouled or stops working because of sand or
sea growth, use a stiff brush to clean it. You may sand the surface with a
fine-grit wet or dry sandpaper (#320 grade or finer), but this will affect the
performance of the unit when the boat is moving at higher speeds.
The paddle wheel mechanism may become jammed by dirt or grit.
Work this out of the mechanism, then clean the unit with soap and water
or alcohol.
Troubleshooting Suggestions
If the unit is not working correctly, there may be a simple cause. Before
you call for service help, please check these points:
The Fishfinder display unit will not turn on –
1. The unit may actually be operating, but the contrast may have been
set to the “full light” or “full dark” setting. Turn on the unit by pressing
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L750 Fishfinder: Installation and Operation Handbook
the Power and Enter buttons at the same time to change all settings
to the factory defaults. See the default settings on page 68.
2. If the power wiring includes a fuse, it may be blown. Also check the
circuit breaker or main battery switch.
3. You may have reversed the power connections. Follow the DC
power lines all the way back to the battery. The red wire should
connect to the positive terminal (+) on the battery or power source,
and the black wire should connect to the negative terminal (-) (also
called “ground” or “earth”). If the polarity is not correct, reconnect the
leads properly and check again.
4. The battery or DC power source may not be producing the correct
voltage. The Fishfinder needs at least 10 volts to operate. If the
voltage is lower, check for loose or corroded connections, or a
problem with the power source.
The display unit “freezes” (temporarily or
permanently) –
1. Check that the display has not been stopped using the Chart Speed
setting. (If the adjustment bar is moved all of the way to the left, the
display will freeze.)
2. A source of electrical “noise” may be interfering with the unit’s
operation. Both the transducer cable and the power cable for the
Fishfinder should be routed as far as possible from all other wiring on
the boat.
To locate the source of the noise, turn on the Fishfinder. Next, turn
on each electrical device on the boat, but just supply power to one
device at a time. This may reveal the cause of the problem. Move
the Fishfinder, the other unit, or the wiring. A movement of just a few
inches can make a big difference. If it is necessary to cross any
wires, make the crossing at a right angle.
Start the motor in neutral and increase the RPM speed. This can
reveal a problem with the boat’s alternator. It may help to use
resistor-type spark plugs or spark plug cables on the boat’s motor.
You can also try a noise-suppression filter on the alternator.
3. One of the wiring connections may be loose. All of the connections
should be clean, tight, and insulated. Soldering is the best way of
making these connections. Protect each connection with a piece of
shrink-wrap tubing.
4. The transducer cable may be damaged. Check for any point where
Chapter 5: Maintenance and Troubleshooting
71
the wiring may be pinched or bent. Look for signs that water has
gotten into the cable. If the transducer cable is damaged, the
transducer and cable should be replaced as a unit. Contact your
Raymarine dealer for instructions.
The display unit does not see the bottom or fish –
1. Be sure the display unit is not using the Simulation mode. (If this is
the case, the word “Simulation” will flash on the display.)
2. On a unit with the transom-mount transducer, the transducer may
have “kicked up” because it hit an obstruction. See Fig. 2-8. Move
the transducer down into the working position.
3. The unit may be set for Manual gain or sensitivity, and be using a
very low sensitivity setting. Adjust the manual gain control, or select
Auto gain. You can also reset all of the values to the factory defaults,
by holding down the Enter button as you turn on the unit. See the
default settings on page 68.
4. The transducer may not be vertical. Be sure that the transducer is
aiming straight down, or within 10° of vertical.
5. If the transducer is an in-hull type, be sure that it is installed correctly.
The transducer should be “looking” through just one layer of
fiberglass hull material, no more than 1" (25 mm) thick. The
transducer should be firmly attached to the hull using the correct type
of adhesive/sealant.
6. The face of the transducer may be covered or fouled. Use a stiff
brush to clean it. You may also sand the surface with a fine-grit wet
or dry sandpaper (#320 grade or finer), but this will affect the
performance of the unit when the boat is moving at higher speeds.
7. If the Fishfinder is using the Auto Sensitivity setting, it may be
reacting to an increase in electrical “noise.” As the level of noise
increases, the sensitivity automatically adjusts, and the unit can lose
its ability to see the bottom or fish. Check for problems with the
wiring as described in the section on “Display unit freezes.”
8. The voltage from the power source may be low. This affects the
transmitting power of the Fishfinder. Check the connections as
described in the section on “The display unit freezes.”
The Fishfinder does not display fish arches –
1. Be sure the Fish Symbol feature is turned off. See the instructions
for the System Setup display.
72
L750 Fishfinder: Installation and Operation Handbook
2. The Fishfinder will not display arches unless the boat is moving. If
the boat is stopped, fish will appear on the display as straight lines.
3. The transducer may not be aimed straight down. In order to display
complete arches, the transducer must be vertical.
4. The sensitivity setting may not be high enough. Press the Gain
button and increase the gain or sensitivity setting manually.
The display disappears or is unreliable when the boat
is moving at high speeds –
1. Increased turbulence around the transducer may be “confusing” the
unit. Move the transducer to a location where there is less
turbulence when the boat is moving.
2. If the Fishfinder is using the Auto Sensitivity setting, it may be
reacting to an increase in electrical “noise.” As the level of noise
increases, the sensitivity automatically adjusts, and the unit can lose
its ability to see the bottom or fish. Check for problems with the
wiring as described in the section on “The display unit freezes.”
The display unit shows lots of background “noise” –
1. The unit may be set to use the manual sensitivity adjustment, and
the sensitivity may be set too high. See the information on “Setup
Instructions.”
2. The transducer may be mounted incorrectly, or may be fouled.
Check the mounting as described in Section 2. Clean the transducer
as described earlier in this section.
The depth setting flashes often –
Note: Normally, this indicates that the bottom has moved out of range.
1. The transducer may not be installed correctly, or the signal may not
be reaching the display unit. Recheck the instructions in “Mounting
the Transducer” in Section 2. Check the transducer cable for signs
of damage. If the cable is damaged, the transducer and cable
should be replaced as a unit.
2. The voltage reaching the unit may be low, and this may be affecting
the transmitting power. Check for problems with the wiring as
described in the section on “The display unit freezes.”
Chapter 5: Maintenance and Troubleshooting
73
The speed or log readings are wrong –
1. The paddle wheel on the transducer may be fouled. Clean the parts
as described in the section on “Cleaning Instructions.”
2. Check the speed calibration. Use the item for “Speed Cal” on the
System Setup display. See the instructions in Section 4.
Servicing a Thru-Hull Transducer
If your boat has a thru-hull transducer, you can service it without
removing the boat from the water. The sensor(s) are mounted in a
cylindrical plug in the center of the transducer assembly. If necessary,
you can remove this plug by working from the inside of the boat. The
transducer housing includes a check valve to minimize the water
intrusion when removing the insert. A small amount of water will enter
the boat. This is normal. Immediately after removing the speed insert,
place the dummy insert in the transducer housing. Do not leave the
transducer without the speed or dummy insert in place.
How to Contact Raymarine
For technical support
Please call 1-800-539-5539, extension 2444 or (603) 881-5200,
extension 2444. Our Fax number is 1-603-864-4756.
You may reach our Technical Service Department Monday through
Friday, 8:15 a.m. to 5:00 p.m. Eastern Standard Time or Eastern
Daylight Savings Time. Our Technical Support Specialists are available
to answer questions about installing, operating, and troubleshooting
your Raymarine unit. You may also reach our Technical Support
Department via the Internet. Questions may be addressed directly to:
[email protected]
Or, you may visit the Raymarine World Wide Web site :
www.raymarine.com
For accessories and parts
Please call 1-800-539-5539, extension 2333 or (603) 881-5200
extension 2333.
Many Raymarine accessory items and parts are available through your
L750 Fishfinder: Installation and Operation Handbook
74
authorized Raymarine dealer. However, if you are in need of an item not
available through your retailer, please contact the Customer Service
Department. The Customer Service Department is available Monday
through Friday, 8:15 a.m. to 5:00 p.m. Eastern Time. Please have the
Raymarine part number ready when calling to place an order. (See the
Optional Accessory List in this manual on page 2.) If you are not sure
which item you need for your Raymarine unit, please contact our
Technical Support Department before placing your order: 1-800-5395539 ext. 2444.
For product repair and service
In the unlikely event your Raymarine unit should develop a problem,
please return the unit to the Raymarine unit from which it was
purchased. Your Raymarine dealer is best equipped to handle your
service needs. Service may also be obtained by returning your unit to
Raymarine’s Product Repair Center:
Raymarine Product Repair Center
22 Cotton Road, Unit D
Nashua, NH 03063-4219-USA
When your unit arrives at our Product Repair Center, we will mail you a
postcard acknowledging this. We will do everything possible to return
your unit as quickly as possible.
To inquire about the status of your unit, you can reach our Product
Repair Center by calling 1-800-539-5539, extension 2118. Please keep
a record of the serial number of your unit, and have this number ready
when you call.
Raymarine Europe
In Europe and other locations, support, service and accessories are
available from Raymarine Europe:
Raymarine Limited
Anchorage Park, Portsmouth
PO3, 5TD, England
Att. Service Department
Chapter 5: Maintenance and Troubleshooting
75
Parts Listing
1b
1d
1a
1c
1e
3
2
1f
1
Key No.
1
1a
1b
1c
1d
1e
1f
2
3
Part
Front facia (consisting of 1a - 1f)
Blanking plate
Blanking plate seal
Window
Window gasket
Front cover
Light guide (green ring)
Keypad mat - lower
Keypad mat - upper
Part No.
G625704-1
Part of
item
R112
G625709-1
Note - See page 2 for a list of accessories and options.
Qty.
1
1
1
L750 Fishfinder: Installation and Operation Handbook
76
3
2
1
4
Key No.
1
2
3
4
Part
Keypad PC board - upper
LCD module
Case seal
Keypad PC board - lower
Part No.
R113
R069
R070
R068
Qty.
1
1
1
1
Chapter 5: Maintenance and Troubleshooting
77
1
2
1
3
Key No.
1
2
3
Part
Washers (part of 2)
Rear cover
Main PC board assembly
Part No.
W095
G625706-1
Qty.
2
1
1
L750 Fishfinder: Installation and Operation Handbook
78
Chapter 6: Specifications
General Information
Display panel
7" FSTN high-contrast LCD with 4 levels of gray
Panel dimensions
5.5" H (140 mm) x 4.2" W (105 mm)
No. of dots
320 x 240
LCD contrast
Adjustable, with temperature compensation
Backlight
Cold cathode, with 5 levels including off
Operating modes
Standard mode
Digital mode
Dual mode
Sidelooker mode
Keys
Silicon rubber
Memory backup
Non-volatile, no battery required
Power source
10.0 to 16.0 V DC
Power consumption
backlight off - approx. 6 W
backlight on - approx. 12 W
Dimensions (w/o bracket)
8" H (240 mm) x 6.87" W (175 mm)
3.27” D (83 mm)
Weight
3 lbs, 14 oz (1.75 kg)
Waterproofing
U.S.C.G., CFR 46
EMI resistance
IEC 945
Fishfinder Functions
Range
Auto or manual
FT (feet)
5, 10, 15, 20, 30, 40, 50, 60, 80, 100, 150, 180, 200, 250,
300, 400, 600, 800, 1000, 1500, 2000, 2500
FA (fathoms)
1, 2, 3, 4, 5, 8, 10, 15, 20, 25, 30, 40, 50, 60, 80,100, 150,
200, 250, 300, 450
M (meters)
2, 4, 6, 8, 10, 15, 20, 25, 30, 40, 50, 60, 80, 100,150, 200,
300, 400, 500, 600, 800
Zoom size
x2, x4, x6, x8
Chart speed
Freeze, slow, medium, fast
White line
On/ Off
Alarms
Shallow, deep, fish
Chapter 6: Specifications
79
Reset distance log
0 to 999 units
Fish symbols
8 sizes
Output power
500 W(rms)
Frequency
50 kHz, 200 kHz or dual operation
Transducer beam angle
200kHz: 16° @ -6db
50kHz: 65° @ -6db
Depth units
Feet, fathoms, meters
Numerical display
3 digits
Water temperature
32.0 to 99.9°F (0 to 37.0°C)
Boat speed units
Mph, kph, knots (0 to 70)
Sensitivity
Auto or manual
Connector Diagram
2
5
1
7
4
3
6
Fig. 6-1 Connector Diagram
(Viewed from rear of L750 chassis)
Pin no.
Function
Wire Color
1
Not used
Orange
2
Not used
Yellow
3
Battery negative
Black
4
Shield
In insulation
5
Battery positive
Red
6
Not used
Green
7
Not used
Blue
L750 Fishfinder: Installation and Operation Handbook
80
GAIN
DISPLAY
VRM/EBL
MARKS
MULTI
RANGE
ALARMS
POWER
Fig. 6-2 Dimensions
ENTER
CLEAR
MENU
Glossary
81
Glossary of Terms
Aft:
Near or toward the rear part of the boat (nautical
term).
Background noise: False or meaningless echo returns produced by
bubbles, water turbulence, or debris
Bow:
The front of the boat (nautical term).
Cavitation:
Air bubbles in the water which affect the readings
of a transducer. These are normally caused by
mounting the transducer at an incorrect angle or
location.
Chart Speed:
The rate at which echoes scroll across the display.
Cursor:
On a setup display, the place where the unit is
ready to make a change or enter new information.
This point is highlighted. You can move up or
down the list or display using the up- and downcontrols on the Trackpad.
Deadrise angle:
The slope or angle of the underside of the hull,
measured in the side-to-side direction.
Default value:
A value or setting which is pre-loaded into the unit
at the factory.
Fairing block:
A block used when mounting a thru-hull
transducer. The fairing block shims the
transducer to align it on a perfect horizontal plane
versus the rise of the hull.
Fathom:
A unit of depth equal to 6 feet.
Frequency:
The rate at which a sound source vibrates, or the
rate at which a sound wave changes.
Fore:
Near or toward the front part of the boat (nautical
term).
Gain:
The ability of a receiver to distinguish between
echoes of different strengths. In general, use a
higher gain setting for deep water, and a lower
setting for shallow water.
Keel:
The center of the hull, running from the bow to the
stern.
L750 Fishfinder: Installation and Operation Handbook
82
kHz:
“Kilo-Hertz” – a measure of frequency (For
example, 200 kHz = 200,000 oscillations per
second.)
Kick-up bracket:
A bracket which is installed on the transom of a
boat and holds the transducer in place. When the
transducer strikes an obstruction, it is designed to
release or “kick up” out of the water to prevent any
damage.
Knot:
One nautical mile per hour (1.15 statute miles per
hour).
LCD:
“Liquid Crystal Display” - A technology used to
produce flat-panel displays.
Nautical mile:
6076 feet
Port:
Left side of the boat, when facing the bow (nautical
term).
PVDF:
“Poly Vinylidene Fluoride” – A unique polymer
plastic that has the ability to convert sound waves
into electrical impulses. PVDF is used in the
optional Sidelooker transducer for excellent
detection of fish in the horizontal direction.
Range:
The depth scale for the unit. The maximum
distance the unit will be able to see at a particular
range setting.
Sensitivity:
The ability of a receiver to distinguish between
echoes of different strengths. In general, use a
higher sensitivity setting for deep water, and a
lower setting for shallow water.
Starboard:
Right side of the boat, when facing the bow
(nautical term).
Statute mile:
5280 ft.
Stern:
The rear of a boat (nautical term).
Thermocline:
A level in the water where two areas of differing
water temperature meet. Sometimes a
thermocline can reflect sonar waves and present
a false display.
Glossary
83
Transducer:
A device which sends and receives high
frequency sound waves through the water.
Transom:
The rear-most part of the boat’s hull, often a flat
panel.
White Line:
A feature used to help display fish near the
bottom. This feature helps to show the difference
between weak returns (including fish near the
bottom) and strong returns (including the bottom
itself).
Zoom:
A way of magnifying or enlarging part of the
display to give a better view of a section of the
water.
Limited Warranty Certificate
Raymarine warrants each new Light Marine/Dealer Distributor Product to be of good materials and
workmanship, and will repair or exchange any parts proven to be defective in material and workmanship under
normal use for a period of 2 years/24 months from date of sale to end user, except as provided below.
Defects will be corrected by Raymarine or an authorized Raymarine dealer. Raymarine will, except as
provided below, accept labor cost for a period of 2 years/24 months from the date of sale to end user. During
this period, except for certain products, travel costs (auto mileage and tolls) up to 100 round trip highway miles
(160 kilometres) and travel time of 2 hours, will be assumed by Raymarine only on products where proof of
installation or commission by authorized service agents, can be shown.
Warranty Limitations
Raymarine Warranty policy does not apply to equipment which has been subjected to accident, abuse or
misuse, shipping damage, alterations, corrosion, incorrect and/or non-authorized service, or equipment on
which the serial number has been altered, mutilated or removed.
Except where Raymarine or its authorized dealer has performed the installation, it assumes no responsibility
for damage incurred during installation.
This Warranty does not cover routine system checkouts or alignment/calibration, unless required by
replacement of part(s) in the area being aligned.
A suitable proof of purchase, showing date, place, and serial number must be made available to Raymarine or
authorized service agent at the time of request for Warranty service.
Consumable items, (such as: Chart paper, lamps, fuses, batteries, styli, stylus/drive belts, radar mixer
crystals/diodes, snap-in impeller carriers, impellers, impeller bearings, and impeller shaft) are specifically
excluded from this Warranty.
Magnetrons, Cathode Ray Tubes (CRT), TFT Liquid Crystal Displays (LCD) and cold cathode fluorescent
lamps (CCFL), hailer horns and transducers are warranted for 1 year/12 months from date of sale. These items
must be returned to a Raymarine facility.
All costs associated with transducer replacement, other than the cost of the transducer itself, are specifically
excluded from this Warranty.
Overtime premium labor portion of services outside of normal working hours is not covered by this Warranty.
Travel cost allowance on certain products with a suggested retail price below $2500.00 is not authorized.
When/or if repairs are necessary, these products must be forwarded to a Raymarine facility or an authorized
dealer at owner’s expense will be returned via surface carrier at no cost to the owner.
Travel costs other than auto mileage, tolls and two (2) hours travel time, are specifically excluded on all
products. Travel costs which are excluded from the coverage of this Warranty include but are not limited to:
taxi, launch fees, aircraft rental, subsistence, customs, shipping and communication charges etc. Travel costs,
mileage and time, in excess to that allowed must have prior approval in writing.
TO THE EXTENT CONSISTENT WITH STATE AND FEDERAL LAW:
(1) THIS WARRANTY IS STRICTLY LIMITED TO THE TERMS INDICATED HEREIN, AND NO
OTHER WARRANTIES OR REMEDIES SHALL BE BINDING ON RAYMARINE INCLUDING
WITHOUT LIMITATION ANY WARRANTIES OF MERCHANTABLE OR FITNESS FOR A
PARTICULAR PURPOSE.
(2) Raymarine shall not be liable for any incidental, consequential or special (including punitive or multiple)
damages.
All Raymarine products sold or provided hereunder are merely aids to navigation. It is the responsibility of the
user to exercise discretion and proper navigational skill independent of any Raymarine equipment.
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