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SERVICE MANUAL
SPEAKER SYSTEM
No.21092
Apr. 2002
COPYRIGHT
2002 VICTOR COMPANY OF JAPAN, LTD.
SX-DD3
SX-DD3
Contents
Safety precautions --------------------------------------------------------1-2
Disassembly method -----------------------------------------------------1-3
Description of major ICs -------------------------------------------------1-6,7
Area suffix
E ------ Continental Europe
EN ------- Northern Europe


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SX-DD3
1-2
1. This design of this product contains special hardware and many circuits and components specially for safety
purposes. For continued protection, no changes should be made to the original design unless authorized in
writing by the manufacturer. Replacement parts must be identical to those used in the original circuits. Services
should be performed by qualified personnel only.
2. Alterations of the design or circuitry of the product should not be made. Any design alterations of the product
should not be made. Any design alterations or additions will void the manufacturer`s warranty and will further
relieve the manufacture of responsibility for personal injury or property damage resulting therefrom.
3. Many electrical and mechanical parts in the products have special safety-related characteristics. These
characteristics are often not evident from visual inspection nor can the protection afforded by them necessarily
be obtained by using replacement components rated for higher voltage, wattage, etc. Replacement parts which
have these special safety characteristics are identified in the Parts List of Service Manual. Electrical
components having such features are identified by shading on the schematics and by (
) on the Parts List in
the Service Manual. The use of a substitute replacement which does not have the same safety characteristics
as the recommended replacement parts shown in the Parts List of Service Manual may create shock, fire, or
other hazards.
4. The leads in the products are routed and dressed with ties, clamps, tubings, barriers and the like to be
separated from live parts, high temperature parts, moving parts and/or sharp edges for the prevention of
electric shock and fire hazard. When service is required, the original lead routing and dress should be
observed, and it should be confirmed that they have been returned to normal, after re-assembling.
5. Leakage currnet check (Electrical shock hazard testing)
After re-assembling the product, always perform an isolation check on the exposed metal parts of the product
(antenna terminals, knobs, metal cabinet, screw heads, headphone jack, control shafts, etc.) to be sure the
product is safe to operate without danger of electrical shock.
Do not use a line isolation transformer during this check.
Plug the AC line cord directly into the AC outlet. Using a "Leakage Current Tester", measure the leakage
current from each exposed metal parts of the cabinet, particularly any exposed metal part having a return
path to the chassis, to a known good earth ground. Any leakage current must not exceed 0.5mA AC (r.m.s.).
Alternate check method
Plug the AC line cord directly into the AC outlet. Use an AC voltmeter having, 1,000 ohms per volt or more
sensitivity in the following manner. Connect a 1,500
10W resistor paralleled by a 0.15 F AC-type capacitor
between an exposed metal part and a known good earth ground.
Measure the AC voltage across the resistor with the AC
voltmeter.
Move the resistor connection to each exposed metal part,
particularly any exposed metal part having a return path to
the chassis, and meausre the AC voltage across the resistor.
Now, reverse the plug in the AC outlet and repeat each
measurement. Voltage measured any must not exceed 0.75 V
AC (r.m.s.). This corresponds to 0.5 mA AC (r.m.s.).
1. This equipment has been designed and manufactured to meet international safety standards.
2. It is the legal responsibility of the repairer to ensure that these safety standards are maintained.
3. Repairs must be made in accordance with the relevant safety standards.
4. It is essential that safety critical components are replaced by approved parts.
5. If mains voltage selector is provided, check setting for local voltage.
Good earth ground
Place this
probe on
each exposed
metal part.
AC VOLTMETER
(Having 1000
ohms/volts,
or more sensitivity)
1500
10W
0.15 F AC TYPE
!
Burrs formed during molding may
be left over on some parts of the
chassis. Therefore, pay attention to
such burrs in the case of
preforming repair of this system.
In regard with component parts appearing on the silk-screen printed side (parts side) of the PWB diagrams, the
parts that are printed over with black such as the resistor (
), diode (
) and ICP (
) or identified by the " "
mark nearby are critical for safety.
(This regulation does not correspond to J and C version.)


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SX-DD3
1-3
Remove the eleven screws A attaching the amplifier
assembly.
Pull out the amplifier assembly.
Remove the felt sheet from vibration prevention of
the wire connector in the reverse side of the amplifier
assembly.
Remove the connection of 3 wire connectors in the
reverse side of the amplifier assembly.
Note: Before attaching the amplifier assembly the felt
sheet is wound to the wire connector for the
vibration prevention of the wire connector.
Attaching the tie band from the top of the felt
sheet.
1.
2.
Disassembly method
Removing the amplifier assembly
(See Fig. 1~3)
Remove the amplifier assembly.
Remove the volume knob.
Remove the three screws B attaching the rear panel .
Removing the rear panel
(See Fig. 4)
1.
2.
3.
4.
Fig. 1
Fig. 3
Rear panel
Cabinet
A
Cord
connecter
Amp.
A
A
A
Rear panel
Amp. assay
B
Vol. knob
Felt sheet
Cabinet
Tie band
Felt sheet
Fig. 4


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SX-DD3
1-4
Remove the amplifier assembly.
Remove the three screws C attaching the bracket.
Pull out the power switch board to the rear side.
Remove the wire connecter CN899.
Note: As occasion demands the tie band is cut.
Removing the power switch board
(See Fig. 5)
1.
2.
3.
Remove terminal board
(See Fig. 6,7)
Remove the rear panel.
Remove the two screws D attaching the bracket b.
Removing the connection of connector CN811 and
CN821, pull out the terminal board.
Remove the wire connecter CN851.
1.
2.
3.
Remove the rear panel.
Remove terminal board.
Removing the connection of wire connector CN891
and CN881.
Remove the six screws E attaching the amplifier
board.
1.
2.
3.
Remove amplifier board
(See Fig. 8)
Fig. 5
Terminal
board
CN899
Power switch
board
power switch
knob
Bracket a
Bracket b
Phase switch
knob
Terminal board
CN811
/CN821
CN851
Amp.
board
CN881
CN891
CN821
Fig. 6
Fig. 8
Fig. 7
E
E
D
C


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SX-DD3
1-5
Cautions:
Remove the rear panel.
Remove the power switch board.
Remove the terminal board.
Remove the four screws F which are fixing the
transformer.
Remove the transformer
(Fig. 9)
1.
2.
3.
Remove the Bottom board.
Remove the four screws G which are fixing the
bottom board.
Remove the four screws H which are fixing the
woofer speaker.
Pull out woofer speaker.
Remove the speaker wire.
Remove the woofer
(Fig. 10~12)
1.
2.
3.
4.
A black wire terminal is not a ground.
These goods should not make the
terminal black of a speaker absolutely
touched from the structure of a system to
the ground of a chassis etc.
Fig. 9
Fig. 10
Transformer
Fig. 11
Fig. 12
Woofer
Speaker wire
(red, black)
Cabinet
Bottom board
Woofer
F
G
G
H
H