SERVICE MANUAL
No.21177
Oct. 2002
COPYRIGHT
2002 VICTOR COMPANY OF JAPAN, LTD.
SX-DW303
POWERED SUBWOOFER
Safety precautions
Disassembly method
Description of major ICs
1- 2
1- 3
1- 6~7
Contents
Area Suffix
SX-DW303
E --- Continental Europe
SX-DW303
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 current 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 measure the AC voltage across the resistor.
Now, reverse 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.)
SX-DW303
1-3
Remove the eleven screws A attaching the amplifier
assembly.
Remove the amplifier assembly to the front from the
cabinet.
Remove the connection of the wire connector at the
back side of the amplifier assembly.
Remove the connection of the speaker wire from the
speaker terminal at the back side of the amplifier
assembly.
1.
2.
Disassembly method
Removing the amplifier assembly
(See Fig. 1, 2)
Prior to performing the following procedures, remove
the amplifier assembly.
Remove the volume nob & frequency nob.
Remove the seven screws B attaching the rear
panel.
Removing the rear panel
(See Fig. 3)
1.
2.
3.
4.
Fig.1
Fig.2
Fig.3
Amplifier
Assembly
Cabinet
Wire connecter
A
Frequency nob
A
A
A
Speaker
terminal
Volume nob
B
B
Amplifier
Assembly
Amplifier
Assembly
Cabinet
Rear panel
SX-DW303
1-4
1.
2.
3.
Prior to performing the following procedures, remove
the rear panel.
Remove the two screw
marked C attaching the
bracket a.
Pull out the bracket a toward you.
Remove the connection of the wire connector
Removing the power cord
(See Fig.4, 5)
Removing the power supply assembly
bord
(See Fig.6 )
1.
2.
3.
4.
5.
Prior to performing the following procedures, remove
the rear panel and the power cord.
Remove the screw marked D that is fixing the
bracket b.
Remove the three screws marked E that are fixing
the bracket c.
Remove the wire connecter CN102 and CN503.
Remove the connection of the connector CN951 and
CN952.
Pull out the amplifier assembly board toward you.
Removing the amplifier assembly board
(See Fig.5, 6)
Prior to performing the following procedures, remove
the rear panel and remove the power cord.
Remove the amplifier board assembly.
Remove the six screws marked F attaching the
power board assembly.
Pull out the power supply board assembly toward
you.
1.
2.
3.
Fig.5
Fig.6
Fig.4
Amplifier
assembly
board
Bracket a
E
C
Power
cord
CN901
E
D
CN503
CN102
CN951
CN952
Bracket b
Bracket c
F
F
Power supply
assembly
board
SX-DW303
1-5
1.
2.
3.
4.
Remove the three sheets of the cushion sheet
marked G.
Remove the six screws marked H attaching the
bottom plate.
Remove the two screws marked I attaching the
bottom plate.
Pull out the bottom plate toward you.
Removing the Bottom plate
(See Fig.7, 8)
1.
2.
Prior to performing the following procedures, remove
the bottom plate.
Remove the four screws J attaching the woofer.
Pull out the woofer toward you.
Removing the woofer
(See Fig.9)
Fig.8
Fig.9
Fig.7
J
Woofer
Cabinet
G
G
Bottom
plate
I
J
H
H
H
Bottom
plate