JVC TH-A75R User manual

SERVICE MANUAL
COPYRIGHT © 2003 VICTOR COMPANY OF JAPAN, LTD. No.21189
2003/02
TH-A75R
DVD DIGITAL CINEMA SYSTEM
21189200302
TH-A75R
TABLE OF CONTENTS
1 Important Safety Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
2 Disassembly method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6
3 Adjustment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-16
4 Description of major ICs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-17
XV-THA75R
SP-WA75
SP-XSA75 and SP-XCA75
STANDBY
COMPACT
SUPERVIDEO
DIGITAL¥EX
PRO LOGIC
D V D D I G I T A L C I N E M A S Y S T E M
RGB
PHONES
SOURCE VOLUME
RMÐSTHA75R
DVD CINEMA SYSTEM
CHANNEL/ZOOM VOLUMETVVOL
TUNING
STOP
DIMMER
PAUSE
FF/
/REW
TV/VIDEO MUTING
REC
PLAY
DOWN UP
MEMORY STROBE
DVD VCR 1
AUDIO
VIDEO/
TV SOUND
ANGLE
FM/AM
SUBTITLE DECODE
RETURN DIGEST
VFP
TOP MENU MENU
CONTROL EFFECT
S.WFR TEST
SLEEP
TV
VCR
SETTING
TV RETURN
ENTER
ON
SCREEN
CHOICE
FM MODE
123
456
789
10
0
+10
100+
TV AUDIO
VCR
SOUND
PTY SEARCH
DVD
RDS
TA/NEWS/INFO
PTY PTY
RDS DISPLAY
SURROUND OFF
DSP
CENTER
Ð
+
Ð
+
Ð
+
Ð
+
SURR-L SURR-R
S-BACK
Ð
+
ADJUST
O.T.
REPLAY
Area Suffix
B ---------------------- U.K.
E ---- Continentl Europe
EN --- Northern Europe
EV ----- Eastern Europe

TH-A75R
1-2 (No.21189)
SECTION 1
Important Safety Precautions
1.1 Safety Precautions
(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 man-
ufacturer. Replacement parts must be identical to those
used in the original circuits. Services should be per-
formed 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 characteris-
tics are often not evident from visual inspection nor can the
protection afforded by them necessarily be obtained by us-
ing replacement components rated for higher voltage, watt-
age, etc. Replacement parts which have these special safety
characteristics are identified in the Parts List of Service Manu-
al. Electrical components having such features are iden-
tified by shading on the schematics and by ( ) on the
Parts List in the Service Manual. The use of a substitute re-
placement which does not have the same safety character-
istics as the recommended replacement parts shown in the
Parts List of Service Manual may create shock, fire, or oth-
er 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, particular-
ly any exposed metal part having a return path to the
chassis, to a known good earth ground. Any leakage cur-
rent 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 ohm 10W resistor
paralleled by a 0.15 µF 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.).
1.2 Warning
(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.
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 pre-
forming 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. (Except the JC version)

TH-A75R
(No.21189)1-3
1.5 Safety Precautions (U.K only)
(1) This design of this product contains special hardware and many circuits and components specially for safety purposes. For con-
tinued protection, no changes should be made to the original design unless authorized in writing by the manufacturer. Replace-
ment parts must be identical to those used in the original circuits.
(2) Any unauthorised design alterations or additions will void the manufacturer's guarantee; furthermore the manufacturer cannot
accept responsibility for personal injury or property damage resulting therefrom.
(3) Essential safety critical components are identified by ( ) on the Parts List and by shading on the schematics, and must never
be replaced by parts other than those listed in the manual. Please note however that many electrical and mechanical parts in
the product have special safety related characteristics. These characteristics are often not evident from visual inspection. Parts
other than specified by the manufacturer may not have the same safety characteristics as the recommended replacement parts
shown in the Parts List of the Service Manual and 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.
1.5.1 Warning
(1) Service should be performed by qualified personnel only.
(2) This equipment has been designed and manufactured to meet international safety standards.
(3) It is the legal responsibility of the repairer to ensure that these safety standards are maintained.
(4) Repairs must be made in accordance with the relevant safety standards.
(5) It is essential that safety critical components are replaced by approved parts.
(6) If mains voltage selector is provided, check setting for local voltage.
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.

TH-A75R
1-4 (No.21189)
1.6 Preventing 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.
1.6.1 Grounding to prevent damage by static electricity
Static electricity in the work area can destroy the optical pickup (laser diode) 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 sheet) 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.
(3) Handling the optical pickup
• In order to maintain quality during transport and before installation, both sides of the laser diode on the replacement optical
pickup are shorted. After replacement, return the shorted parts to their original condition.
(Refer to the text.)
• Do not use a tester to check the condition of the laser diode in the optical pickup. The tester's internal power source can easily
destroy the laser diode.
1.7 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) Cut off the shorted part of the flexible cable using nippers, etc. 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 cable carefully as it may break when subjected to strong force.
(4) I t is not possible to adjust the semi-fixed resistor that adjusts the laser power. Do not turn it.
1.8 Attention when traverse unit is decomposed
*Please refer to "Disassembly method" in the text for the DVD pickup unit.
• Apply solder to the short land sections before the flexible wire is disconnected from the connector CN101 on the DVD servo board.
(If the flexible wire is disconnected without applying solder, the DVD pickup may be destroyed by static electricity.)
• In the assembly, be sure to remove solder from the short land sections after connecting the flexible wire.
DVD mechanism assembly
CN101
DVD servo board
Short land sections
Flexible wire

TH-A75R
(No.21189)1-5
1.9 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 laser
radiation and is equipped with safety switches which
prevent 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.
CAUTION
Please use enough caution not to see the beam directly
or touch it in case of anadjustment or operation check.
VARNING
Osynlig laserstrålning är denna del är öppnad och spårren är
urkopplad. Betrakta ej strålen.
VARO
Avattaessa ja suojalukitus ohitettaessa olet alttiina näkymät-
tömälle lasersäteilylle. Älä katso säteeseen.
ADVARSEL
Usynlig laserstråling ved åbning, når sikkerhedsafbrydere er
ude af funktion. Undgå udsasttelse for stråling.
ADVARSEL
Usynlig laserstråling ved åpning, når sikkerhetsbryteren er avs-
lott. unngå utsettelse for stråling.
REPRODUCTION AND POSITION OF LABELS
WARNING LABEL
CLASS 1
LASER PRODUCT

TH-A75R
1-6 (No.21189)
SECTION 2
Disassembly method
2.1 Main body section
2.1.1 Removing the top cover (See Figs.1 to 4.)
(1) From the right and left sides of the main body, remove the
four screws A attaching the top cover. (See Figs.1 and 2.)
(2) From the back side of the main body, remove the two
screws B attaching the top cover. (See Fig.3.)
(3) Lift the rear section of the top cover, slide the top cover
slightly in the direction of the arrow. (See Fig.4.)
(4) Disengage the engagement sections a of the top cover
from the main body. (See Fig.4.)
Fig.1
Fig.2
Fig.3
Fig.4
Top cover
A
Top cover
A
Rear panel
Top cove
r
B
Top cover
a

TH-A75R
(No.21189)1-7
2.1.2 Removing the front panel assembly (See Figs.5 to 8.)
• Remove the top cover.
(1) From the left side of the main body, push the section b of
the slide cam using the screw driver, etc. (See Fig.5.)
(2) Pull out the tray. (See Fig.5.)
(3) Push the tray fitting assembly of the tray in the direction of
the arrow and then remove the tray fitting assembly. (See
Fig.6.)
(4) Return the tray into the DVD mechanism assembly.
(5) From the bottom side of the main body, remove the four
screws C attaching the front panel assembly. (See Fig.7.)
(6) From the top side of the main body, remove the two screws
D attaching the front panel assembly. (See Fig.8.)
(7) Disconnect the card wires from the connectors CN206 and
CN207 on the main board. (See Fig.8.)
(8) Remove the screw E attaching the lug wire. (See Fig.8.)
(9) While opening the hooks c to the right and left sides of the
front panel assembly in the direction of the arrow 1, remove
the front panel assembly in the direction of the arrow 2.
(See Fig.8.)
Reference:
then hold the card wire to the sections d of the barrier.
(See Fig.8.)
Fig.5
Fig.6
Fig.7
Fig.8
Slide cam
Front panel assembly
b
Tray
Tray
Tray fitting assembly
Front panel assembly
CFront panel assembly
Chassis base
Main board
Front panel assembly
Lug wire
Hook c
Barrier CN207
2
1
CN206
d
D E
Hook c
1

TH-A75R
1-8 (No.21189)
2.1.3 Removing the DVD mechanism assembly (See Fig.9.)
• Remove the top cover.
• Remove the front panel assembly.
(1) From the top side of the main body, remove the barrier.
(2) Disconnect the card wires from the connectors CN208 and
CN209 on the main board.
(3) Remove the three screws F attaching the DVD mechanism
assembly.
(4) Take out the DVD mechanism assembly from the chassis
base.
Fig.9
2.1.4 Removing the DSP board (See Figs.10 and 11.)
• Remove the top cover.
(1) From the top side of the main body, disconnect the card
wires from the connectors CN591 and CN592 on the DSP
board. (See Fig.10.)
(2) From the back side of the main body, remove the three
screws G attaching the DSP board. (See Fig.11.)
(3) Remove the DSP board from the section e of the barrier,
take out the DSP board. (See Fig.10.)
Reference:
When attaching the DSP board, hang the DSP board to
the section e of the barrier. (See Fig.10.)
2.1.5 Removing the tuner (See Figs.10 and 11.)
• Remove the top cover.
(1) From the top side of the main body, disconnect the card
wire from the connector CN1 on the tuner. (See Fig.10.)
(2) From the back side of the main body, remove the two
screws H attaching the tuner. (See Fig.11.)
Fig.10
Fig.11
Main board
CN209 CN208
F
F
Card wire
Card wire
Barrier
Chassis base
DVD
mechanism
assembly
DSP board
Card wires
Card wire Tuner
Barrier
CN1
CN591
CN592 e
Rear panel
H
G

TH-A75R
(No.21189)1-9
2.1.6 Removing the main board (See Figs.12 and 13.)
• Remove the top cover.
• Remove the DSP board.
• Remove the tuner.
(1) From the top side of the main body, disconnect the card
wires from the connectors (CN201, CN202, CN204,
CN206-CN209) on the main board. (See Fig.12.)
(2) Remove the screw J and two screws K attaching the main
board. (See Fig.12.)
(3) From the back side of the main body, remove the five
screws L attaching the main board. (See Fig.13.)
Fig.12
Fig.13
2.1.7 Removing the amplifier board (See Figs.13 to 16.)
• Remove the top cover.
(1) From the top side of the main body, disconnect the card
wires from the connectors CN701 and CN702 on the am-
plifier board (See Fig.14.)
(2) Remove the three screws M attaching the amplifier board.
(See Fig.13.)
(3) From the back side of the main body, remove the four
screws N attaching the amplifier board. (See Fig.15.)
(4) Disconnect the connector CN703 on the amplifier board,
take out the amplifier board. (See Fig.14.)
(5) Remove the six screws P attaching the heat sink to the am-
plifier board. (See Fig.16.)
Fig.14
Fig.15
Fig.16
Card wires
CN206
CN204
CN201
CN202
CN207 CN208 CN209
Card wires
K
J
K
Main board
Rear panel
L
Amplifier board
CN703
CN702CN701
M
M
Rear panel
N
Amplifier board
PP
PHeat sink

TH-A75R
1-10 (No.21189)
2.1.8 Removing the fan motor (See Figs.17 and 18.)
• Remove the top cover.
• Remove the amplifier board.
(1) From the top side of the main body, remove the fan cover.
(See Fig.17.)
(2) Remove the tie band banding the fan motor wire and then
disconnect the fan motor wire from the connector CN174
on the power board. (See Fig.17.)
(3) Remove the screw Q and screw R attaching the fan brack-
et. (See Fig.17.)
(4) Remove the two screws S attaching the fan motor to the
fan bracket. (See Fig.18.)
Reference:
When attaching the screw Q, attach the lug wire of the
front panel assembly at the same time.
Fig.17
Fig.18
2.1.9 Removing the power board (See Fig.19.)
• Remove the top cover.
• Remove the amplifier board.
(1) From the top side of the main body, disconnect the card
wires from the connectors CN172 and CN173 on the power
board.
(2) Remove the tie band banding the fan motor wire and then
disconnect the fan motor wire from the connector CN174
on the power board.
(3) Disconnect the power cord from the connector CN101 on
the power board.
(4) Remove the screw T and three screws U attaching the
power board.
Fig.19
Power board
CN174
Tie band
Fan motor wire
Fan motor
Fan bracket
Lug wire
Front panel assembly
Fan cover
R
Q
Fan motor
Fan bracke
t
S
Power cord
CN101
CN173
CN174
U
CN172
U
T
Card wires
Tie band
Power board
Fan motor wire

TH-A75R
(No.21189)1-11
2.2 Front panel assembly section
• Remove the top cover.
• Remove the front panel assembly.
2.2.1 Removing the jack board (See Fig.1.)
(1) From the inside of the front panel assembly, disconnect the
wire from the connector CN403 on the switch board.
(2) Remove the two screws V attaching the jack holder, take
out the jack board together the jack holder.
Fig.1
2.2.2 Removing the switch board (See Figs.2 and 3.)
(1) From the inside of the front panel assembly, disconnect the
wire from the connector CN403 on the switch board. (See
Fig.2.)
(2) Remove the eight screws W attaching the switch board,
take out the switch board. (See Fig.2.)
Reference:
In the assembly, attach the switch board after attaching
the push buttons and light lens as before. (See Fig.3.)
Fig.2
Fig.3
2.2.3 Removing the standby board (See Fig.4.)
From the inside of the front panel assembly, remove the two
screws X attaching the standby board.
Fig.4
2.3 DVD mechanism section
• Remove the top cover.
• Remove the DVD mechanism assembly.
2.3.1 Removing the tray (See Figs.1 and 2.)
(1) From the left side of the DVD mechanism assembly, push
the slide cam in the direction of the arrow 1 and then pull
out the tray in the direction of the arrow 2. (See Fig.1.)
(2) Push the tray stoppers a in the direction of the arrow 3, pull
out the tray in the direction of the arrow 4. (See Fig.2.)
2.3.2 Attaching the tray (See Fig.2.)
When attaching the tray, insert the tray to the rail of the DVD
mechanism assembly and then push the tray in the DVD mech-
anism assembly.
Fig.1
Fig.2
Front panel assembly
CN403
Wire
Jack holder
Jack board Switch board
V
Front panel assembly
CN403
Wire
Switch board
W
W
Push button Push button
Light lens
Front panel assembly
Standby board
X
2
Tray
Slide cam
1
DVD mechanism assembly
Tray
Tray stoppers a
3
4

TH-A75R
1-12 (No.21189)
2.3.3 Removing the tray (See Fig.3.)
(1) From the bottom side of the DVD mechanism assembly,
disconnect the card wires from the connectors CN201 and
CN202 on the DVD servo board.
Caution:
Be sure to solder the short land sections b on the flexible
wire before disconnecting the flexible wire from connec-
tor CN101 on the DVD servo board.
If the flexible wire is disconnected without attaching sol-
der, the DVD pickup unit may be destroyed by static
electricity.
(2) Release the locks of the connector CN101 (in the direction
of the arrow 1) on the DVD servo board, disconnect the
flexible wire.
(3) Release the locks of the connector CN101 on the DVD ser-
vo board in the direction of the arrow 1, disconnect the flex-
ible wire.
Caution:
In the assembly, be sure to remove solders from the
short land sections b after connecting the flexible wire to
the connector CN101 on the DVD servo board.
(4) While pushing the claw c of the DVD mechanism assembly
in the direction of the arrow 2, remove the DVD servo board
in an upward direction.
Fig.3
2.3.4 Removing the clamper base (See Fig.4.)
(1) From the top side of the DVD mechanism assembly, re-
move the four screws A attaching the clamper base.
(2) Remove the clamper base from the bosses d of the loading
base in an upward direction, remove the clamper base
from the sections e while sliding it in the direction of the ar-
row.
Fig.4
2.3.5 Removing the tray drive board (See Fig.5.)
• Remove the clamper base.
(1) From the bottom side of the DVD mechanism assembly, re-
move the solders from the soldered sections f on the tray
drive board.
(2) Remove the screw B attaching the tray drive board to the
DVD mechanism assembly.
Fig.5
DVD mechanism assembly
Claw c
Claw c
CN201
CN202
CN101
DVD servo board
11
222
Short land sections b
Card wire
Card wire
Flexible wire
Clamper base
AA
Boss d
Boss dA A Section e
Section e
DVD mechanism assembly
Loading base
Soldered sections f
Motor
B
Tray drive board
DVD mechanism assembly

TH-A75R
(No.21189)1-13
2.3.6 Removing the motor (See Fig.6.)
• Remove the clamper base.
• Remove the tray drive board.
(1) From the top side of the DVD mechanism assembly, re-
move the belt of the pulley gear.
Note:
Take care not to attach grease on the belt.
(2) Remove the screw C attaching the motor to the DVD mech-
anism assembly.
Fig.6
2.3.7 Removing the DVD traverse mechanism assembly
(See Figs.7.)
• Remove the DVD servo board.
• Remove the clamper base.
(1) From the top side of the DVD mechanism assembly, re-
move the four screws D attaching the DVD traverse mech-
anism assembly to the loading base.
(2) Take out the DVD traverse mechanism assembly from the
loading base.
Fig.7
2.3.8 Removing the DVD pickup unit (See Figs.8 to 10.)
• Remove the DVD servo board.
• Remove the clamper base.
• Remove the DVD traverse mechanism assembly.
(1) From the top side of the DVD traverse mechanism assem-
bly, remove the screw E attaching the plate and torsion
spring. (See Fig.8.)
(2) Remove the shaft from the section g and then remove the
shaft from the section h. (See Fig.9.)
(3) Disengage the section i of the DVD pickup unit and then re-
move the DVD pickup unit with the shaft.
(4) Pull the shaft out of the DVD pickup unit.
(5) Remove the two screws F attaching the SW. actuator.
2.3.9 Attaching the DVD pickup unit (See Figs.8,10 to 12)
Reference:
Refer to the explanation of "Removing the DVD pickup unit" on
the preceding page.
(1) Attach the SW. actuator and shaft to the DVD pickup unit.
(See Fig.10.)
(2) Engage the section i of the DVD pickup unit to the shaft of
the DVD traverse mechanism assembly first, and set the
both ends of the shaft of the DVD pickup unit in the sections
g and h of the DVD traverse mechanism assembly. (See
Fig.11.)
(3) Slide the DVD pickup unit all the way in the direction of the
arrow. (See Fig.12.)
(4) Mesh the lead screw to the section j of DVD pickup unit and
then set the end of the lead screw to the section k. (See
Fig.12.)
(5) Attach the torsion spring. (See Fig.8.)
(6) Attach the plate. (See Fig.8.)
Fig.8
DVD mechanism assembly
Belt
C
Motor
Pulley gear
DVD traverse mechanism assembly
D D
DD
Loading base
E
Plate
Torsion spring DVD pickup unit
DVD traverse mechanism assembly

TH-A75R
1-14 (No.21189)
Fig.9
Fig.10
Fig.11
Fig.12
DVD pickup unit
Shaf
t
Section h
Section g
Section i
Shaft
DVD pickup unit
F
SW. actuator
Section i
DVD traverse mechanism assembly
Shaft
Section
Section h
Section k
Section j
Lead scre
w
DVD pickup unit

TH-A75R
(No.21189)1-15
2.3.10 Removing the spindle motor board (See Figs.13 and
14.)
• Remove the DVD servo board.
• Remove the clamper base.
• Remove the DVD traverse mechanism assembly.
(1) From the top side of the DVD traverse mechanism assem-
bly, remove the feed motor wire that is soldered to the spin-
dle motor board. (See Fig.13.)
(2) From the bottom side of the DVD traverse mechanism as-
sembly, remove the three screws G attaching the spindle
motor board. (See Fig.14.)
Fig.13
Fig.14
2.3.11 Removing the feed motor (See Figs.15 to 17.)
• Remove the DVD servo board.
• Remove the clamper base.
• Remove the DVD traverse mechanism assembly.
(1) From the top side of the DVD traverse mechanism assem-
bly, remove the feed motor wire that is soldered to the spin-
dle motor board. (See Fig.15.)
(2) Remove the screws H attaching the feed holder assembly
and then take out the feed holder assembly. (See Fig.15.)
(3) Remove the screw J attaching the thrust spring. (See
Fig.16.)
(4) Remove the feed gear and lead screw in the direction of the
arrow. (See Fig.16.)
(5) Remove the two screws K attaching the feed motor. (See
Fig.17.)
Fig.15
Fig.16
Fig.17
Remove the solders.
DVD traverse mechanism assembly
Spindle motor board
Feed moto
r
wire
G
G
DVD traverse mechanism assembly
H
Feed motor
H
Remove the solders.
DVD traverse mechanism assembly
Feed motor
wire
Spindle motor board
Feed holder assembly
Feed holder assembly
J
Feed motor
Feed gear
Lead screw
Thrust spring
Feed holder assembly
K

TH-A75R
1-16 (No.21189)
SECTION 3
Adjustment
3.1 Test mode
(1) The AC cord is connected after pushing the STOP key and the EJECT key of a main body.
(2) Change to test mode, FL indicate "TEST ??". (?? is version)
At this time, TV monitor indicate the firm number " ".
(3) Press PAUSE key of the main body, EEPROM initialize is start.
FL indicate "RDS", EEPROM initialize is complete.
(4) Release the test mode by power to off.
3.2 Up grade
3.2.1 How to UPGRADE
(1) Power to on then mode to DVD.
(2) Set the recorded disc.
(Down loaded the up grade program "TH-A75 -Firmware Update Procedure" from Audio Products DIV.
Technological Material of JS-Net .)
(3) FL indicate "UPGRADE", press cursol key of the remote controller.
(4) TV monitor indication the UPGRADE condition.
(5) Upgrade is complete, disc is automatically eject then finish the upgrade.
3.2.2 After UPGRADE
After upgrade, it is should done the EEPROM initialize and confirm the firm number.
(1) Tray close then release the AC cord.
(2) The AC cord is connected after pushing the STOP key and the EJECT key of a main body.
(3) Change to test mode, FL indicate "TEST ??". (?? is version)
In this time, confrim the TV monitor indicate the firm number "114".
(4) EEPROM initialize start by press the PAUSE key of main body.
FL indicate "RDS", EEPROM initialize is complete.
(5) Release the test mode by power to off.

TH-A75R
(No.21189)1-17
SECTION 4
Description of major ICs
4.1 UPD784215AGC194 (IC531) : CPU
• Pin layout
• Pin function
1 ~ 25
75 ~ 51
50
~
26
76
~
100
Pin No. Symbol I/O Function
1~8 - - Not use
9VDD-+3.0V
10 X2 I Main system clock input
11 X1 I Main system clock input
12 VSS - GND
13 XT2 - OPEN
14 XT1 I Connect to VSS
15 RESET I Reset for Flash write
16 - - Not use
17 INT0 I Error input0 (detect UNLOCK)
18 INT1 I Error input1 (detect Non Audio)
19 DZF I GND
20~22 - - Not use
23 AVDD - The same potential as VDD
24 AV REF0 - The same potential as VSS
25 - - Not use
26 CS1 I Chip select input port
27 CS2 I Chip select input port
28 CS3 I Chip select input port
29 CS4 I Chip select input port
30~32 - - Not use
33 AVSS - The same potential as VSS
34, 35 - - Not use
36 AV REF1 - The same potential as VDD
37 RX O For flash write
38 TX O For flash write
39 - - Not use
40 DSP_COM I Command (serial 1)
41 DSP_STS O Status (Serial 1)
42 DSP_CLK I Clock (Serial 1)
43 DSP_RDY I Ready
44 - - Not use
45 MIDIO_IN I Data in (Serial 0)
46 MIDIO_OUT O Data out (Serial 0)
47 MICK O Clock (Serial 0)
48 HREQ I HREQ
49 SS O Slave select
50,51 - - Not use
52 DSP_RST O DSP RESET
53 - - Not use
54 DA_CS O Chip select output
55 - - Not use
56 PD/DA O Power down output (RESET)
57 PD O Power down output (RESET)
58~63 - - Not use
64 CODEC_D-OUT O Data out
65 CODEC_D-IN I Data in
66 CODEC_CLK O Clock
67 CODEC_CS O Chip select output
68 DEBUG1 O Debug out port
69 DEBUG2 O Debug out port
70 DEBUG3 O Debug out port
71 GEBUG4 O Debug out port
72 GND - GND
73~75 - - Not use
76 EQ O EQ
77 CTR_TONE O Center tone
78 3D O 3D-Phonic
79, 80 - - Not use
81 VDD - +3.0V
82, 83 - - Not use
84 ANA/T.TUNE O ANALOG./T.TONE
85 LFE.MIX O LFE MIX CONTROL
86 LEF_OUT O LFE OUT CONTROL
87 - - Not use
88 S.MUTE O S.MUTE
89~93 - - Not use
94 TEST O Usual "VSS"
95~100 - - Not use
Pin No. Symbol I/O Function

TH-A75R
1-18 (No.21189)
4.2 39VF0207CWHQ01 (IC524) : 2 Mbit multi-purpose flash memory
• Pin layout • Block diagram
• Pin function
Top view
A11
A9
A8
A13
A14
A17
WE#
VDD
NC
A16
A15
A12
A7
A6
A5
A4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
OE#
A10
CE#
DQ7
DQ6
DQ5
DQ4
DQ3
VSS
DQ2
DQ1
DQ0
A0
A1
A2
A3
Y-Decoder
I/O Buffers
and
Data Latches
Address Buffers
and
Latches
X-Decoder
DQ7 - DQ0
Memory Address
OE#
CE#
WE#
SuperFlash
Memory
Control Logic
Pin No. Symbol Function
1 - 6 A11,A9,A8
A13,A14,A17
Address inputs
7 WE# Write enable
8 VDD Power supply
9 NC Not connect
10 - 20 A16,A15,A12
A7 - A0
Address inputs
21 - 23 DQ0 - DQ2 Data inputs/outputs
24 VSS Ground
25 - 29 DQ3 - DQ7 Data inputs/outputs
30 CE# Chip enable
31 A10 Address input
32 OE# Output enable

TH-A75R
(No.21189)1-19
4.3 MM74HCT32MTC-X (IC521) : Quad 2 input OR gate
• Pin layout & Block diagram
• Truth table
4.4 74LCX373MTC-X (IC512,IC513) : Octal D-type latch
• Pin layout • Truth table
X: Don't care
Z: High impedance
Qn: Q outputs are latched at the time when the LE input is tak-
en to a low logic level.
• Block diagram
11A
21B
31Y
42A
52B
62Y
7
14
13
12
11
10
9
8GND
V
CC
4B
4A
4Y
3B
3A
3Y
(TOP VIEW)
INPUTS OUTPUT
ABY
LLL
LHH
HLH
HHH
1OE
2Q0
3D0
4D1
5Q1
6Q2
7
20
19
18
17
16
15
14D2
VCC
Q7
D7
D6
Q6
Q5
D5
(TOP VIEW)
8D3
9Q3
10GND
13
12
11
D4
Q4
LE
INPUTS OUTPUT
OE LE D Y
HXXZ
LLXQn
LHLL
LHHH
Q
L
D
D0
3
2
Q0
11
1
LE
OE
Q
L
D
D1
4
5
Q1
Q
L
D
D2
7
6
Q2
Q
L
D
D3
8
9
Q3
Q
L
D
D4
13
12
Q4
Q
L
D
D5
14
15
Q5
Q
L
D
D6
17
16
Q6
Q
L
D
D7
18
19
Q7

TH-A75R
1-20 (No.21189)
4.5 AK4586VQ (IC511) : A/D, D/A Converter
• Pin layout
• Pin function
44 - 34
12 - 22
11 - 1 23 - 33
Pin No. Symbol I/O Function
1 XTO O X'tal output pin
2 XTI I X'tal input pin
EXTCLK I External master clock input pin
3 TVDD - Output buffer power supply pin, 2.7V~5.5V
4 VDSS - Digital Ground pin, 0V
5 DVDD - Digital power supply pin, 4.5V~5.5V
6 TX O Transmit channel (through data) output pin
7 MCKO O Master clock output pin
8 LRCK I/O Input/Output channel clock pin
9 BICK I/O Audio serial data clock pin
10 SDTO O Audio serial data output pin
11 SDTI1 I DAC1 audio serial data input pin
12 SDTI2 I DAC2 audio serial data input pin
13 SDTI3 I DAC3 audio serial data input pin
14 INT0 O Interrupt 0 pin
15 INT2 O Interrupt 1 pin
16 CDTO O Control data output pin in 4-wire serial control mode
CAD1 I Chip address 1 pin in I2C bus control mode
17 CDTI I Control data input pin in 4-wire serial control mode
SDA I/O Control data input/output pin in I2C bus control mode
18 CCLK I Control data clock pin in 4-wire serial control mode
SCL I Control data clock pin in I2C bus control mode
19 CSN I Chip select pin in 4-wire serial control mode
CAD0 I Chip address 0 pin in I2C bus control mode
20 DZF2 O Zero input detect 2 pin
OVF O Analog input overflow detect pin
21 AVSS - Analog ground pin, 0V
22 AVDD - Analog power supply pin, 4.5V~5.5V
23 VREFH I Positive voltage reference input pin, AVDD
24 VCOM O Common voltage output pin, AVDD/2
25 DZF1 O Zero input detect 1 pin
26 LOUT3 O DAC3 Lch analog output pin
27 ROUT3 O DAC3 Rch analog output pin
28 LOUT2 O DAC2 Lch analog output
29 ROUT2 O DAC2 Rch analog output pin
30 LOUT1 O DAC1 Lch analog output pin
31 ROUT1 O DAC1 Rch analog output pin
32 LIN I Lch analog input pin
33 RIN I Rch analog input pin
34 PCDD - PLL power supply pin, 4.5V~5.5V
35 R - External resistor pin
36 PVSS - Pll ground pin, 0V
37 RX4 I Receiver channel 4 pin (internal biased pin)
38 SLAVE I Slave mode pin
39 RX3 I Receiver channel 3 pin (internal biased pin)
40 TST I Test pin
41 RX2 I Receiver channel 2 pin (internal biased pin)
42 I2C I Control mode select pin
43 RX1 I Receiver channel 1 pin (internal biased pin)
44 PDN I Power-Down & Reset pin