Airmar SB646 User Manual

Small Switchbox with Remote Switch

Model: SB646

Follow the precautions below for optimal product
performance and to reduce the risk of property damage,
personal injury, and/or death.

17-565-01 rev.02 09/06/11

WARNING: Always wear safety goggles and a dust
mask when installing to prevent personal injury.

WARNING: The power must be ‘OFF’ before
proceeding with the installation.

INSTALLATION INSTRUCTIONSOWNER’S GUIDE &

Figure 1. SB646 Switchbox with remote switch

Copyright © 2011 Airmar Technolog y Corp.

WARNING: The power supply voltage must be 10 - 32
VDC.

WARNING: A safe installation requires a 0.5 amp fast­blow fuse or circuit breaker.

CAUTION: To reduce electrical interference from
other electrical wiring and any on-board equipment with
strong magnetic fields such as radar equipment, radio
transmitters, boat engines, generators, etc., separate
the cables by at least 1m (3').

CAUTION: Be careful not to tear the cable jackets
when passing them through bulkheads and other parts
of the boat. Use grommets to prevent chaffing. Use
deck glands to prevent water seeping into the boat.

CAUTION: Use a multimeter to check the polarity and
the connections to the power supply before applying
power to the transducer(s).

IMPORTANT: Please read the instructions completely
before proceeding with the installation. These
instructions supersede any other instructions in your
instrument manual if they differ.

Tools & Materials

Safety glasses
Dust mask
Grommets (some installations)
Deck glands (some installations)
Cutting pliers
Phillips screwdrivers
Pencil
Electric drill
Drill bits:

Switchbox 3mm or 1/8"

Remote switch 11mm or 1/2" spade bit
Sandpaper
Weak solvent (such as alcohol)
Wire strippers
Heat shrink tubing
Small blade screwdriver
Pliers some installations)
Adjustable wrench
Cable ties (some installations)

Locating Switchbox, Remote Switch & Cables

IMPORTANT: Be sure to allow an extra 25 cm (10") of cable to

make the connections within the switchbox.

Applications

• Single transmission line transducers and echosounders only

• Echosounders with power rating of 1kW or less.
Do not use with 2kW echosounders.

• One echosounder can be connected to two transducers. The
transducers must have C32 or C332 cable.

• One transducer can be connected to two echosounders. The
echosounder must be dual-frequency with a single
transmission-line. The transducer must have C32 or C332
cable.

• One echosounder can switch between a wide-beam and a
narrow-beam transducer. Pair a wide-beam SS264W with one of
the narrow-beam models such as: B258, B260, or M260. Both
transducers must have C32 or C332 cable.

Switchbox—Select a convenient dry mounting location for the
water-resistant switchbox about 1–2 m ( 3' – 5') from the
echosounder(s).

• Retrofit—If the transducer(s) and echosounder(s) are already
installed, select a location with easy access to the cable(s). Be
sure the cable(s) will be long enough to make the necessary
connections. Allow an extra 25 cm (10") for wiring ease.

• New installation—Install the transducer(s) and echosounder(s)
before connecting the switchbox. Plan the cable runs.

Remote Switch—Locate the remote switch on the dash panel or
other convenient location near the echosounder. Check the
backside for any obstructions such as cables and wires.

• Minimum clearance on backside 36mm (1-1/2")

• Maximum panel thickness 6mm (1/4”)

Running the Cables

Figure 2. Preparing the cable (SS264W cable shown)

64mm (2 1/2")

remove cable jacket and

10mm
(3/8")

cable
jacket

inner bare
(depth)

outer bare
(shield)

remove
insulation

foil shielding

heat-shrink
tubing

Copyright © 2008 Airmar Technolog y Corp.

If new equipment is being installed, route the transducer cable(s),
the echosounder cable(s), the power cable, and the remote switch
cable to the proposed location of the switchbox before beginning
the installation.

• To reduce electrical interference from other electrical wiring
and any on-board equipment with strong magnetic fields such
as radar equipment, radio transmitters, boat engines,
generators, etc., separate the cables by at least 1m (3').

• Use grommets when passing cables through bulkheads and
other parts of the boat to prevent chafing.

• Use deck glands where necessary to prevent water seepage
into the boat.

• Allow an extra 25 cm (10") of cable for wiring ease.

• Do not fasten the cables in place at this time.

Installing the Remote Switch

IMPORTANT: It may be easier to wire the remote switch before

installing it in the mounting surface.

1. Strip 60mm (2-1/2") of the cable jacket and foil shielding from
one end of the C2 cable (see Figure 2).

2. Strip 10mm (3/8") of conductor insulation from the end of each
insulated wire in each cable.

3. Protect the cable’s foil shielding from causing a short by using
heat shrink tubing around the jacket where the wires emerge
from the cable. The tubing must overlap the wires a minimum of
6mm (1/4").

4. On the switch, unscrew the plastic ring and discard. It will not be
used. Unscrew the hexagonal nut and set aside.

5. Connect the blue wire to one of the screw terminals on the back
of the remote switch and the black wire to the other terminal
(see Figure 3). Either wire can be connected to either screw
terminal. It will not affect the performance of the switch.

Connect each wire by loosening a screw. Wrap the striped end
of the wire around the threads of the screw and tighten it again.

6. From the backside of the mounting surface, push the toggle
through the mounting hole. With the notch on the threaded stem
facing the word ‘Wide-Beam’ or ‘A’ on the label, screw the nut
against the surface. Tighten it with an adjustable wrench.

7. Screw the water-resistant boot onto the toggle switch.

Preparing the Cables

1. Allowing an extra 25 cm (10") for wiring ease, cut each cable to
length. Do not fasten the cables in place at this time.

2. Push approximately 200mm (8") of each cable through the
appropriate fitting. Follow the diagram on the switchbox cover
(see Figure 1). Be careful not to damage the circuit board.

3. Strip 60mm (2-1/2") of the cable jacket and foil shielding from
the cut end of each cable (see Figure 2).

Hole Drilling

1. Hold the switchbox at the selected location and mark the
position of the four screw holes.

NOTE: If the switchbox will be mounted on a vertical surface,
face the compression fittings to the side to avoid any possibility
of water seeping into the box (see Figure 1).

2. At the marked locations, drill 3mm or 1/8" holes to a depth of
10mm (3/8"). Do not fasten the switchbox in place at this time.

3. At the planned location for the switch, use the label as a
template to mark the hole.

4. Drill a 3mm or 1/8" pilot hole. Using a 11mm or 1/2" drill bit, drill
the hole for the switch.

5. Sand the area around the hole, inside and out. Clean the
surface with a weak solvent such as alcohol to ensure the label
will adhere properly.

6. Apply the switch label by removing the backing from the
adhesive and pressing the label firmly into place.

2

4. Strip 10mm (3/8") of conductor insulation from the end of each
colored wire in each cable.

5. Protect each cable’s foil shielding from causing a short inside
the switchbox by using heat shrink tubing around the jacket
where the wires emerge from the cable. The tubing must
overlap the wires a minimum of 6mm (1/4").

boot

notch
faces word
“widebeam”
or “A” on label

hexagonal nut

screw terminals

Figure 3. Installing the switch

Copyright © 2008 Airmar Technol ogy Corp.