JVC TH-M55 Service Manual
MB075200310
SERVICE MANUAL
DVD DIGITAL THEATER SYSTEM
TH-M55
Area suffix
J ----------------------------- U.S.A.
C -------------------------- Canada
SP-THM55C
SP-THM55F SP-THM55F SP-THM55F SP-THM55F
XV-THM55
SP-PWM55
TABLE OF CONTENTS
1 PRECAUTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
2 SPECIFIC SERVICE INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7
3 DISASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8
4 ADJUSTMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-34
5 TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-39
COPYRIGHT © 2003 VICTOR COMPANY OF JAPAN, LIMITED
No.MB075
2003/11
SPECIFICATION
Audio section
Total Harmonic Distortion 0.02%
Audio input sensitivity/
Impedance (at 1 kHz)
Video section
Color System NTSC
Horizontal Resolution 500 lines
Signal-to-Noise Ratio 64 dB
Video output level Composite 1.0 V(p-p)/75 Ω
Video input sensitivity/
Impedance (VCR IN)
Tuner section
Tuning Range FM 87.5 MHz to 108.0 MHz
General
Power Requirements AC 120 V, 60 Hz
Power Consumption 20 W (at operation), 1.0 W (in standby mode)
Dimensions (W × H × D) 400 mm × 85 mm × 386 mm (15-3/4 inches × 3-3/8 inches × 15-1/14 inches)
Mass 4.6 kg (10.2 lbs)
Amplifier section
Front/Center/Surround 100 W per channel, RMS at 4 Ω at 1 kHz, with 10 % total harmonic distortion.
Subwoofer 120 W, RMS at 4 Ω at 100 Hz, with 10 % total harmonic distortion.
Speaker section
Speaker unit 16 cm (6-5/16 inches) Bass-reflex, Magnetically Shielded
Frequency Range 30 Hz to 200 Hz
General
Power Requirements AC 120 V, 60 Hz
Power Consumption 150 W (at operation), 0 W (in standby mode)
Dimensions (W × H × D) 216 mm × 353 mm × 485 mm (8-9/16 inches × 13-15/16 inches × 19-1/8 inches)
Mass 12.0 kg (26.5 lbs)
Speakers Woofer 10.0 cm (3-15/16 inches)
Power Handling Capacity 100 W
Impedance 4 Ω
Frequency Range 65 Hz to 20 kHz
Dimensions (W × H × D) 140 mm × 228 mm × 167 mm (5-9/16 inches × 9 inches × 6-5/8 inches)
Mass 1.9 kg (4.2 lbs)
Speakers Woofer 8.0 cm (3-3/16 inches) × 2
Power Handling Capacity 100 W
Impedance 4 Ω
Frequency Range 65 Hz to 20 kHz
Dimensions (W × H × D) 326 mm × 119 mm × 164 mm (12-7/8 inches × 4-11/16 inches × 6-1/2 inches)
Mass 2.4 kg (5.3 lbs)
Remote control (1), Batteries (2), FM antenna (1), AM loop antenna (1), Power cord (1), System cord (1), Composite video cord (1)
Speaker codes (1)
5 m (16 ft) For satellite (front left/right) and center speakers (3)
10 m (32 ft) For satellite speakers (surround left/right) (2) (The length of the above speaker cords are approximate.)
NOTE : This value is measured at System cord CONNECTOR for reference.
Analog input AUDIO IN (VCR) 290 mV/47 kΩ
Digital input* DIGITAL IN (DBS) (OPTICAL) -21 dBm to -15 dBm (660 nm ±30 nm)
* Corresponding to Linear PCM, Dolby Digital, and DTS Digital Surround (with sampling freque ncy - 32 kHz, 44.1 kHz, 48 kHz)
S-video-Y 1.0 V(p-p)/75 Ω
S-video-C 0.286 V(p-p)/75 Ω
Component-Y 1.0 V(p-p)/75 Ω
Component-PB/PR 0.7 V(p-p)/75 Ω
Composite 1.0 V(p-p)/75 Ω
S-video-Y 1.0 V(p-p)/75 Ω
S-video-C 0.286 V(p-p)/75 Ω
AM 530 kHz to 1710 kHz
Tweeter 4.0 cm (1-5/8 inches) Bass-reflex, Magnetically Shielded
Tweeter 4.0 cm (1-5/8 inches) Bass-reflex, Magnetically Shielded
Center unit
Subwoofer
Satellite Speaker
Center Speaker
Accessories
Design and specifications are subject to change without notice.
1-2 (No.MB075)
SECTION 1
PRECAUTION
1.1 Safety Precautions
(1) This design of th is product contains special hardw are 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 manufacturers 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 reassembling.
(5) Leakage shock hazard testing
After reassembling 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, 1,000Ω per volt or more sensitivity
in the following manner. Connect a 1,500Ω 10W resistor
paralleled by a 0.15µF 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 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.).
AC VOLTMETER
(Having 1000
ohms/volts,
or more sensitivity)
0.15 F AC TYPE
Place this
probe on
1500 10W
Good earth ground
1.2 Warning
(1) This equipment has been designed and manufactured to
meet international safety standards.
(2) It is the legal resp onsibility 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 compone nts are replaced
by approved parts.
(5) If mains voltage selector is provided, check setting for local
voltage.
1.3 Caution 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.
1.4 Critical parts for safety
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. When replacing them, be sure to use the parts of the
same type and rating as specified by the manufacturer.
(This regulation dose not Except the J and C version)
each exposed
metal part.
(No.MB075)1-3
1.5 Preventing static electricity
1.5.1 Grounding to prevent damage by static electricity
Electrostatic discharge (ESD), which occurs when static electricity stored in the body, fabric, etc. is discharged, can destroy the laser
diode in the traverse unit (optical pickup). Take care to prevent this when performing repairs.
1.5.2 About the earth processing for the destruction prevention by static electricity
Static electricity in the work area can destroy the optical pickup (laser dio de) in devices such as DVD players.
Be careful to use proper grounding in the area where repairs are being performed.
(1) Ground the workbench
Ground the workbench by laying conductive material (such as a conductive sh eet) or an iron plate over it before placing the
traverse unit (optical pickup) on it.
(2) Ground yourself
Use an anti-static wrist strap to release any static electricity built up in your body.
(caption)
Anti-static wrist strap
Conductive material
(conductive sheet) or iron plate
1.5.3 Handling the optical pickup
(1) In order to maintain quality during transport and before installation, both sides of the laser diode on the replacement optical pick-
up are shorted. After replacement, return the shorted parts to their orig inal condition. (Refer to the text.)
(2) Do not use a tester to che ck the condition of the laser diode in the optical pickup. The tester's internal power source can easily
destroy the laser diode.
1.5.4 Handling the traverse unit (optical pickup)
(1) Do not subject the traverse unit (optical pickup) to strong shocks, as it is a sensitive, complex unit.
(2) Remove solder of the short lands on the flexible wire after replacing the optical pickup. For specific details, refer to the replace-
ment procedure in the text. Remove the anti-static pin when replacing the traverse unit.
Be careful not to take too long a time when attaching it to the connector.
(3) Handle the flexible wire carefully as it may break when subjected to strong force.
(4) It is not possible to adjust the semi-fixed resistor that adjusts the laser power. Do not turn it.
1.5.5 Attention when traverse unit is decomposed
*Please refer to "Disassembly method" in the text for the DVD pickup.
• Apply solder to the short circuit points before the flexible wire is disconnected from the connector on the DVD pickup.
(If the flexible wire is disconnected without applying solder, the DVD pickup may be destroyed by static electri city.)
• In the assembly, be sure to remove solder from the short circuit points after connecting the flexible wire.
Short circuit points
DVD pickup
DVD changer mechanism assembly
1-4 (No.MB075)
1.6 Important for laser products
1.CLASS 1 LASER PRODUCT
2.DANGER : Invisible laser radiation when open and
inter lock failed or defeated. Avoid direct exposure to
beam.
3.CAUTION : There are no serviceable parts inside the
Laser Unit. Do not disassemble the Laser Unit.
Replace the complete Laser Unit if it malfunctions.
4.CAUTION : The compact disc player uses invisible
laserradiation and is equipped with safety switches
whichprevent emission of radiation when the drawer
is open and the safety interlocks have failed or are
de
feated. It is dangerous to defeat the safety switches.
5.CAUTION : If safety switches malfunction, the laser is
able to function.
6.CAUTION : Use of controls, adjustments or
performance of procedures other than those specified
herein may result in hazardous radiation exposure.
!
Please use enough caution not to
see the beam directly or touch it
in case of an adjustment or operation
check.
(No.MB075)1-5
1.7 Importance administering point on the safety
<Main body section>
Power supply board (Forward side)
F901
<SP-PWM55 subwoofer section>
Speaker terminal board (Forward side)
F101
Mother board (Forward side)
F153
F154
1-6 (No.MB075)
Caution: For continued protection against risk of
fire, replace only with same type 1.6A/125V for
F901, 6.3A/125V for F101, 8A/125V for F153 and
F154.
This symbol specifies type of fast operating fuse.
Precaution: Pour eviter risques de feux, remplacez
le fusible de surete de F901 comme le meme type
que 1.6A/125V, et 6.3A/125V pour F101, et 8A/125V
pour F153 et F154.
Ce sont des fusibles suretes qui functionnes rapide.
^
SECTION 2
SPECIFIC SERVICE INSTRUCTIONS
This service manual does not describe SPECIFIC SERVICE INSTRUCTIONS.
(No.MB075)1-7
SECTION 3
r
r
DISASSEMBLY
3.1 Main body section
3.1.1 Removing the metal cover
(See Figs.1 to 4)
(1) From the right and left sides of the main body, remove the
four screws A attaching the metal cover. (See Figs.1 and
2.)
(2) From the back side of the main body, remove the three
screws B attaching the metal cover. (See Fig.3.)
(3) Lift the rear section of the metal cover in the direction of the
arrow while extending the lower sections of the metal cover, release the claws a using a longer screwdriver from the
inside as required. (See Fig.4.)
Note:
Do not damage any parts and boards inside the main body
when releasing the joints a using a longer screwdriver.
B
Metal cover
A
Fig.1
Metal cover
A
Fig.2
Metal cove
Rear panel
Fig.3
Metal cove
Claws a Claws a
Fig.4
1-8 (No.MB075)
3.1.2 Removing the front panel assembly
(See Figs.5 and 6)
• Remove the metal cover.
(1) From the top side of the main body, disconnect the parallel
wires from the connectors (CN408
board. (See Fig.5.)
(2) Disconnect the card wires from the connectors (CN407
CN412) on the main board. (See Fig.5.)
(3) Remove the screw C attaching the earth wire to the main
board. (See Fig.5.)
(4) From the bottom side of the main body, remove the three
screws D attaching the front panel assembly. (See Fig.6.)
(5) Release the two hooks b and hook c from the both and bot-
tom sides of the main body, and remove the front panel assembly in the direction of the arrow. (See Figs.5 and 6.)
, CN409) on the main
Card wire
Main board
,
Card wire
CN407
CN412
C
Earth
wire
CN409
Hook b
Front panel assembly
CN408
Parallel wires
Fig.5
Fig.6
D
Hook b
Hook c
Front panel
assembly
(No.MB075)1-9
3.1.3 Removing the DVD changer mechanism assembly
(See Fig.7)
• Remove the metal cover.
• Remove the front panel assembly.
(1) From the top side of the main bod y, disconnect the card
wires from the connectors (CN405
board.
(2) Remove the four screws E attaching the DVD changer
mechanism assembly to the bottom chassis.
(3) Take out the DVD changer mechanism assembly in an up-
ward direction.
Note:
When attaching the screw E, fit the hole of the DVD changer
mechanism assembly to the bosses d on the bottom chassis.
, CN415) on the main
DVD changer mechanism
assembly
E
Boss d
E
Main board
Boss d
CN405
CN415
Card wires
3.1.4 Removing the rear panel
(See Fig.8)
• Remove the metal cover.
(1) From the back side of the main body, remove the screw F,
nine screws G and three screws H attaching the rear panel.
E
Fig.7
Bottom chassis
FG
HH
G
H
Fig.8
Rear panel
1-10 (No.MB075)
3.1.5 Removing the audio & digital input boa r d
A
(See Figs.9 and 10)
• Remove the metal cover.
(1) From the top side of the main bo dy, disconnect the card
wire from the connector CN401
board. (See Fig.9.)
(2) Remove the screw J attaching the audio & digital input
board. (See Fig.9.)
(3) From the back side of the main body, remove the screw K
and two screws L attaching the audio & digital input board
to the rear panel. (See Fig.10.)
(4) Take out the audio & digital input board from the main
body.
3.1.6 Removing the tuner
(See Figs.9 and 10)
• Remove the metal cover.
(1) From the top side of the main bo dy, disconnect the card
wire from the connector CN1
(2) From the back side of the main body, remove the two
screws M attaching the tuner to the rear panel. (See
Fig.10.)
(3) Take out the tuner from the main body.
3.1.7 Removing the power supply board
(See Figs.9 and 10)
• Remove the metal cover.
(1) From the top side of the main body, disconnect the parallel
wires from the connectors (CN416
the main board. (See Fig.9.)
(2) Remove the three screws N attaching the p ower supply
board. (See Fig.9.)
(3) From the back side of the main body, remove the screw P
attaching the power supply board to the rear panel. (See
Fig.10.)
(4) Take out the power supply bo ard from the main body.
Reference:
Remove the rear panel as required. (See Fig.8.)
on the audio & digital input
on the tuner. (See Fig.9.)
, CN402 to CN404) on
Main board
CN401
CN402
CN416
N
J
Card
wires
CN1 CN403
Tuner
udio & Digital input board
CN404
Fig.9
KL M P
Fig.10
Power supply board
N
Parallel wires
Rear panel
(No.MB075)1-11
3.1.8 Removing the main board
(See Figs.11 to 13)
• Remove the metal cover.
(1) From the top side of the main bod y, disconnect the card
wires from the connectors (CN405, CN407, CN410 to
, CN415) on the main board. (See Fig.11.)
CN412
Disconnect the parallel wires from the connectors (CN416
CN402 to CN404, CN408, CN409) on the main board. (See
Fig.11.)
(2) Remove the screw Q attaching the audio & digital input
board. (See Fig.11.)
(3) From the back side of the main body, remove the five
screws R and three screws S attaching the rear panel. (See
Fig.12.)
(4) Take out the rear panel together the audio & digital inp ut
board and tuner.
(5) From the top side of the main body, remove the screw T
and two screws U attaching the main board to the bottom
chassis. (See Fig.13.)
Note:
When attaching the screw T, attach the earth wire of the front
panel assembly at the same time.
,
CN407
Parallel wire
Card wire
CN412
Card wire
Q
CN401
CN416
Audio & Digital input board
Card wire
CN409
CN410
Card wire
CN411
Tuner
Main board
Card wires
CN405
CN403
Fig.11
Parallel wire
CN408
Parallel wires
CN404
CN415
S
T
U
Earth wire
S
Fig.12
Main board
R
S
Rear panel
Front panel assembly
U
1-12 (No.MB075)
Bottom chassis
Fig.13
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