NorthStar 490 Echosounder User manual

490 ECHO SOUNDER
INSTALLATION MANUAL
Rev B2
Part Number GM491
Northstar Technologies
30 Sudbury Road
Acton, Massachusetts 01720
www.NorthstarNav.com
Service: 978/897-0770
Sales: 978/897-6600

Limited warranty policy
Northstar Technologies, Inc., warrants the Northstar 490 to be free from defects in materials and
workmanship for a period of two (2) years. This warranty applies to the original purchaser and to any
subsequent owner during the warranty period, which begins on the date of shipment of the unit,
F.O.B. Acton, Massachusetts, to an authorized Northstar dealer.
Systems may not be returned to Northstar without a Returned Materials Authorization (RMA) num-
ber. Call the Northstar dealer or Northstar for instructions.
During the unit’s warranty period, Northstar will repair or replace, at its option, any part of the unit it
finds to be defective due to faulty material(s) or workmanship. All such repairs and/or replacements
will be promptly performed by Northstar free-of-charge to the owner, excluding freight costs
incurred in shipping to the factory. Return shipments from Northstar to points within the United
States are made via ground transportation, freight prepaid. Special shipping charges (overnight,
two-day, and so on) are the responsibility of the owner.
To be covered by this warranty, the Northstar equipment must have been in normal use. This war-
ranty does not apply to units with defects caused by improper installation, physical damage, abuse,
tampering, lightning or other abnormal electrical discharge, or to units with defaced or altered serial
numbers, or to units repaired by unauthorized persons or repaired in a manner that violates North-
star’s recommended service procedures.
All repairs and/or replacements made under this warranty must be performed at Northstar’s facilities
in Acton, Massachusetts. Performance of warranty work elsewhere will not be authorized, and North-
star will not pay for any charges for such work. Northstar will not be responsible for payment of any
charges imposed by a Northstar dealer or other party for services requested by and/or performed for
a unit’s owner in connection with this warranty. Such services might include removal of the unit
from a vessel, inspection, packaging, handling, reinstallation, and the like.
Northstar Technologies assumes no responsibility for any consequential losses of any nature with
respect to any of its products or services sold, rendered, or delivered. The foregoing is the only war-
ranty expressed or implied. No other warranty exists.

490 INSTALLATION MANUAL, Revision B2 Page i
Table of Contents
SECTION ONE Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
Welcome to the Northstar 490 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
Who should read this manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Scope of this manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Installation considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
SECTION TWO Installing the transducer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
Safety considerations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
Selecting a transducer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Installation considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Choosing a mounting location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Installing a transducer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
Maintaining a transducer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
SECTION THREE Installing the 490 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Safety considerations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
System components. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
Choosing a mounting location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
Mounting the 490 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
Wiring the 490 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
Powering up, setting up, and powering down the 490 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
Installation-test checklist . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
SECTION FOUR Troubleshooting and servicing the 490 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Troubleshooting common 490 installation problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
Getting technical support. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
Ordering replacement parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
Servicing the 490 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
Returning a 490 for service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28
APPENDIX A Technical specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Page ii 490 INSTALLATION MANUAL, Revision B2

490 INSTALLATION MANUAL, Revision B2 Page 1
SECTION ONE
Introduction
Welcome to the
Northstar 490
An echo sounder is a device that provides information about
the water directly beneath a vessel. The echo sounder system
consists of:
•the Northstar 490 echo sounder sensor
•a Northstar navigation system such as the 961/962 or 957/
958
•a transducer
The 490 is available in two models:
•the model 490-D is a 1000-watt dual channel echo
sounder designed to be used with a transducer having
dual ceramic elements, one each for 50 and 200 kHz
•the model 490-S is a 600-watt single channel echo sounder
designed to be used with a transducer having a single
ceramic element capable of 50 and 200 kHz
In this manual, the term “490” refers to both models. For more
information about the 490-D and 490-S, see ”System
components” on page 14.

SECTION ONE Introduction
Page 2 490 INSTALLATION MANUAL, Revision B2
Who should read
this manual
This manual is for marine technicians who are installing the
Northstar 490 and connecting it with the Northstar 961/962
processor or Northstar 957/958, and a transducer.
Scope of this
manual
In this manual, you’ll find information about the following:
•mounting and wiring the 490
•connecting the 490 to the Northstar 961/962 or 957/958
•installing a transducer (an overview is provided, but for
such details as wiring, see the documentation provided by
the transducer’s manufacturer)
•connecting the 490 to a transducer (see also the
Transducer Connector Instructions—GM492)
•troubleshooting and testing the system
•technical specifications for the 490
For information about obtaining technical support and
returning the 490 for factory service, see “SECTION FOUR
Troubleshooting and servicing the 490” beginning on page 23.
For details about operating the 490 using the 961/962 or 957/
958, see the Northstar 490 Echo Sounder Operations Manual
(GM490).
Installation
considerations
1. Check the shipping carton for any damage, and
immediately report any damage to the carrier. Save all
packing material in case you have to return the 490 to
the factory for repair or evaluation.
2. Unpack the carton, and check its contents. You should
have received:
CAUTION! The following list of installation considerations isn’t
a substitute for all the details in Section Three. To
ensure that you meet all critical installation
parameters, be sure to read that entire section and
follow all of its recommendations.

SECTION ONE Introduction
490 INSTALLATION MANUAL, Revision B2 Page 3
•the Northstar 490 Echo Sounder (-D or -S model)
•10-foot (3-meter) data cable to connect the 490 to the
961/962 or 957/958
•10-foot (3-meter) power cable for the 490
•490 parts kit (containing transducer cable end
connector, backshell, heatshrink tubing, and the
Transducer Connector Instructions—GM492)
•Northstar 490 Echo Sounder Installation Manual
(GM491)
•Northstar 490 Echo Sounder Operations Manual
(GM490)
•warranty card
3. Fill out the warranty card and mail it to Northstar.
4. Review all of the installation requirements as outlined in
Sections Two and Three.
5. Install the transducer, then terminate the cable (see
”Connecting the 490 to a transducer” starting on page
20).
6. Mount the 490. For instructions, see ”Mounting the 490”
on page 16.
7. Connect the 490 to ship’s power and to the 961/962
processor or the 957/958. Connection information begins
on page 17.
With the vessel in the water, turn on the system and verify
proper operation.

SECTION ONE Introduction
Page 4 490 INSTALLATION MANUAL, Revision B2

490 INSTALLATION MANUAL, Revision B2 Page 5
SECTION TWO
Installing the
transducer
Safety
considerations WARNING! Be sure to turn the power off before starting the
installation. Further, it is highly recommended that
you keep power off while you’re performing the
installation. If power is left on or turned on during
the installation, fire, electrical shock, or other
serious injury may occur.
Be sure to ground the equipment to prevent
electrical shock and mutual interference.
Be sure the transducer outputs are tied together
before handling to avoid electrical charge build-up.
WARNING! Be sure to use a 3-amp fuse. Using the incorrect
fuse can result in fire or damage to the 490.

SECTION TWO Installing the transducer
Page 6 490 INSTALLATION MANUAL, Revision B2
Selecting a
transducer
Northstar recommends using an Airmar transducer with the
Northstar’s 490 echo sounder.
CAUTION! Mounting the transducer requires drilling holes
through the hull; make sure the installation does not
cause the vessel to leak. A thru-hull installation
should be performed by a professional installer. Do
not attempt this unless you are fully qualified.
Do not perform a thru-hull installation of the
transducer when the vessel is actually in the water.
Immediately after installing the transducer, be sure
to check for leaks, and don’t leave the vessel in the
water for more than three hours before checking it
again.
Northstar assumes no responsibility for improper
installation of a transducer.
NOTE: Be sure that the transducer doesn’t interfere with
any of the on-board systems. Check all other
systems to ensure that their performance doesn’t
degrade when the transducer is connected.
Table 1: Northstar-recommended transducers
Manufacturer Housing Power Frequency
Airmar B250
(P/N 41-088-1-01)
1 kW 50/200 kHz
Airmar B744V/B44V (with
3-wire speed)
600 W 50/200 kHz

SECTION TWO Installing the transducer
490 INSTALLATION MANUAL, Revision B2 Page 7
To purchase a single transducer, contact GEM Electronics at:
GEM Electronics Company
110 South Acline Avenue
Lake City, South Carolina 29560
Phone [phone]
Fax [phone]
If you are a dealer and want to purchase multiple transducers,
you can reach Airmar Technology Corporation at:
Airmar Technology Corporation (www.airmar.com)
35 Meadowbrook Drive
Milford, New Hampshire 03055-4613
Phone [phone]
Fax [phone]
For a list of transducers that are compatible with the Northstar
490, visit Northstar’s website at:
www.NorthstarNav.com
Installation
considerations
The following basic setup information isn’t a substitute for the
installation instructions provided by the transducer’s
manufacturer. To ensure that you meet all critical installation
parameters, be sure to read and follow all of the requirements
in their instructions. Northstar assumes no responsibility for
improper installation.
Choosing a
mounting
location CAUTION! Do not mount the transducer:
•behind strakes, fittings, or hull irregularities
(mounting in those locations may increase
turbulence, aeration, and cavitation) or near the
keel
•near openings for water intake or discharge
•where it might be loosened by the vessel’s
vibration
•less than four feet away from the Northstar 961/
962 processor to minimize interference

SECTION TWO Installing the transducer
Page 8 490 INSTALLATION MANUAL, Revision B2
The two most common problems with echo sounder
installations stem from noise and cavitation. Either of these
situations can produce poor performance.
Noise occurs when the transducer cable is routed too closely to
noise-producing electronics, such as alternators, AC generators,
radars, etc. To avoid problems with noise, route the transducer
cable by itself (not in a bundle) and away from other wires or
cables and the engine.
Cavitation is similar to hydroplaning. In some cases, air bubbles
will come between the transducer and the water. When this
happens, the transducer can’t get its energy into the water
properly, and won’t be able to detect any echoes. To avoid
cavitation, choose a mounting location with good water flow all
around it at all speeds.
Before any drilling or cutting takes place, carefully choose a
mounting location for the transducer that meets the following
criteria (also see Figure 1 on page 9), depending on the type of
vessel:
•the transducer and its cable are as far as possible from
other electrical cables
•leaves room above the transducer for the transducer’s
stem, housing, and cable
•the path for running the transducer’s cable is reasonably
direct—keep in mind that the transducer cable is 33 feet
long (10 meters). To prevent damage, coil any excess cable
and secure it
•water turbulence and noise are minimal, decreasing the
amount of bubbles passing over the transducer face
•the transducer isn’t behind hull irregularities or near
eroding paint; both indicate areas subject to turbulence
•the transducer is as far as possible from the engine or
propellers, and inboard of the lifting strakes
•the transducer always remains submerged and
perpendicular to the waterline
•the transducer is easily accessible from inside the vessel
for adjustments and maintenance
•the transducer’s ultrasonic beams aren’t obstructed by the
keel, propeller shafts, or any other part of the vessel
•the transducer is parallel with the water surface
•the hull thickness falls within the limits in Table 2 below
(all dimensions are perpendicular to the waterline):
Choose the mounting
location to obtain the best
possible performance from
the transducer and the 490.
Take into account the
vessel’s maximum speed
when selecting a mounting
location, as turbulence can
affect echo sounding
capabilities.

SECTION TWO Installing the transducer
490 INSTALLATION MANUAL, Revision B2 Page 9
Figure 1: Recommended installation locations for a transducer
Table 2: Hull thickness limits
Model Minimum Maximum
AirMar B44V/B744V with fairing 6 mm (1/4 inch) 19 mm (3/4 inch)
AirMar B44V/B744V without fairing 6 mm (1/4 inch) 65 mm (2 1/2 inches)
AirMar B250 with fairing —— 45 mm (1 3/4 inches)
AirMar B250 without fairing 19 mm (3/4 inch) 114 mm (4 1/2 inches)
inboard
pressure waves
1/3 aft
full keel sailboat
displacement hull
(6-12")
fin keel sailboat
150-300mm
LWL
Best location for the transducer
(Load Waterline Length)
step-hull
outboard and I/O
planning hulls

SECTION TWO Installing the transducer
Page 10 490 INSTALLATION MANUAL, Revision B2
Installing a
transducer
A flat-bottom hull provides the best environment for mounting
the transducer: It provides a horizontal surface and a constant
water flow over the transducer, with little turbulence (see
Figure 2 for the recommended transducer incline angle). If the
vessel has a deadrise angle greater than 5 degrees, mount the
transducer on a fairing block to create a horizontal surface and
keep the transducer perpendicular to the waterline (see
Figure 3). You must order the fairing block, if needed, from the
transducer’s manufacturer.
Figure 2: Recommended transducer incline angle
Figure 3: Typical finished thru-hull installation with a fairing block (Airmar B44V)
3° incline
1/3 aft
(Load Waterline Length)
LWL
angle
6–12mm (1/4–1/2")
backing
hull
fairing
multisensor
deadrise
fairing thickness
angle
slope of hull
parallel to
waterline
block
Deadrise angle and fairing thickness (B44V shown)
at narrowest point

SECTION TWO Installing the transducer
490 INSTALLATION MANUAL, Revision B2 Page 11
Maintaining a
transducer
Do not expose the transducer’s face or plastic housing to
gasoline or strong solvents, such as acetone. These solvents can
penetrate and degrade many plastics and reduce their strength.
Using anti-fouling paint The transducer should be coated with water-based anti-fouling
paint to prevent aquatic growth.
Figure 4: Anti-fouling paint areas (for Airmar B44V)
Cleaning a transducer To clean the transducer of heavy debris or foul sea growth, use
a stiff brush or putty knife, but don’t scratch the surfaces.
Check the transducer every few weeks, maximum.
Use sanding sparingly, as repeated sanding may affect the
transducer’s performance at high speeds. For lighter cleaning,
the surface may be wet-sanded with #220 or finer wet/dry
sandpaper.
CAUTION! Use special transducer paint. Other paints may
contain copper, which is conductive and can burn
out the transducer within minutes!
Anti-fouling paint (B44V shown)
Paint outside wall below the lower O-ring
including exposed end, paddle wheel cavity and paddle wheel
Paint exposed housing
lower
O-ring
and bore up 30mm (1-1/4")
paddle wheel
insert
housing
detail

SECTION TWO Installing the transducer
Page 12 490 INSTALLATION MANUAL, Revision B2

490 INSTALLATION MANUAL, Revision B2 Page 13
SECTIONTHREE
Installing the
490
Safety
considerations
WARNING! Be sure to turn the power off before starting the
installation. Further, it is highly recommended that
you keep the power off while you’re performing the
installation. If power is left on or turned on during
the installation, then fire, electrical shock, or other
serious injury may occur.
Be sure to ground the equipment to prevent
electrical shock and mutual interference.
Be sure that the voltage of the power supply is
between 10 and 30 volts DC. Connecting to the
wrong power supply can result in fire or damage to
equipment.
Be sure to use a 3-amp fuse. Using the incorrect
fuse can result in fire or damage to the 490.
CAUTION! Keep the following safe compass distances from
the 490: 1.0 m standard, 0.8 m steering.

SECTION THREE Installing the 490
Page 14 490 INSTALLATION MANUAL, Revision B2
System
components
Figure 5 on page 14 shows a configured 961/962 echo sounder
system, and Figure 6 on page 15 shows a configured 957/958
echo sounder system.
Figure 5: 961/962 echo sounder system components
CAUTION! Be sure that the 490 doesn’t interfere with any of
the on-board systems. Check all other systems to
ensure that their performance doesn’t degrade
when the 490 is turned on.
If the vessel is out of the water when the echo
sounder is turned on, the transducer may be
damaged.
CAUTION! Do not open the 490. There are no serviceable
parts inside. Unauthorized tampering with the unit
will automatically void the warranty.
TRANSDUCER
10-FOOT CABLE
(NORTHSTAR-SUPPLIED)
SHIP’S POWER
NORTHSTAR
961/962
PROCESSOR
NORTHSTAR
961/962
DISPLAY
NORTHSTAR
490 ECHO
SOUNDER
GPS/DGPS
ANTENNA
DATA
INTERFACE
RECOMMENDED:
AIRMAR B250 1000-W TRANSDUCER
FOR THE 490-D
AIRMAR B44V/B744V 600-W TRANSDUCER
FOR THE 490-S
10-FOOT CABLE
(NORTHSTAR-SUPPLIED)
33-FOOT CABLE
(PART OF TRANSDUCER)