JVC TH-A35 User manual

TH-A35
TH-A35
SERVICE MANUAL
DVDDIGITALCINEMASYSTEM
Contents
COPYRIGHT ©2003VICTORCOMPANYOFJAPAN,LTD.
No.22020
Jun. 2003
Safety precautions --------------------------- 1- 2
Preventingstaticelectricity ----------------- 1-3
Important forlaserproducts ---------------- 1- 4
Disassemblymethod ------------------------ 1-5
Descriptionof major ICs -------------------- 1-15
Wiring connection ---------------------------- 1-20
Area Suffix
J ........................ U.S.A.
C ........................ Canada
COMPACT
SUPERVIDEO
DIGITAL
SURROUND
DIGITAL¥EX
PRO LOGIC
VOLUME
PHONES
DSPSORROUND
SOURCE
STANDBY
STANDBY/ON

TH-A35
1-2
Warning
!
CAUTION
Good earth ground
Place this
probe on
each exposed
metal part.
AC VOLTMETER
(Having 1000
ohms/v
1500 10W
olts,
or more sensitivity)
0.15 F AC TYPE
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 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.Thisequipmenthas been designedandmanufacturedto meet internationalsafetystandards.
2.Itisthe legal responsibilityoftherepairer to ensure thatthesesafetystandards are maintained.
3.Repairsmustbe made inaccordance withtherelevant safety standards.
4.Itisessential that safetycriticalcomponentsare replaced byapprovedparts.
5.Ifmainsvoltage selector isprovided,check settingfor 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-A35
1-3
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.
1.1. 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.
1.1.1. Ground the workbench
1. 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.
1.1.2. Ground yourself
1. Use an anti-static wrist strap to release any static electricity built up in your body.
1.1.3. 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 pickup are shorted. After replacement, return the shorted parts to their original condition.
(Refer to the text.)
2. Do not use a tester to check the condition of the laser diode in the optical pickup. The testers internal power
source can easily destroy the laser diode.
1.2. 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 replacement 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. It is not possible to adjust the semi-fixed resistor that adjusts the laser power. Do not turn it.
Conductive material
(conductive sheet) or iron plate
(caption)
Anti-static wrist strap
1M

TH-A35
1-4
1. CLASS 1 LASER PRODUCT
2. CAUTION : Visible and invisible laser radiation when
open and interlock 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
defeated. It is dangerous to defeat the safety switches.
Important for laser products
REPRODUCTION ANDPOSITIONOFLABELS
CLASS1 LABEL
WARNING LABEL
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 an adjustment or
operation check.
VARNING : Osynlig laserstrålning ärdennadelär öppnad
ochspårrenär urkopplad. Betrakta ej strålen.
VARO : Avattaessajasuojalukitus ohitettaessa olet
alttiinanäkymättömällelasersäteilylle. Älä
katsosäteeseen.
ADVARSEL : Usynlig laserstråling vedåbning,når
sikkerhedsafbrydereerude af funktion.
Undgåudsættelsefor stråling.
ADVARSEL : Usynlig laserstråling vedåpning,når
sikkerhetsbrytereneravslott. Unngå
utsettelseforstråling.
CLASS 1
LASER PRODUCT
CLASS 1
LASER PRODUCT

TH-A35
1-5
2. PIN CONFIGURATION
Disassembly method
 Removing the cabinet top
 Removing the tray Door
 Removing the cabinet front
 Removing theTUNER and panel rear
< CHAS, MAIN ASSEMBLY >
 Removing the MPEG BOARD
 Removing the MAIN BOARD
 Removing FAN
 Removing theThermal - Regifer
 Removing theVCD mechanism base assembly
 Removing PWB, AMP
 Removing Power , fruformer
< Front panel ASSEMBLY >
 Removing the FRONT PWB & LED PWB
Commence disassembly of this set by removing the main units and then proceed to the components and
assemblies inside the units.
< MAIN BODY >

TH-A35
1-6
< MAIN BODY >
 Removing the cabinet top
(See Fig.1)
1.Unscrew the 6 serew A
2. Lift the cabinet top by holding the two sides of it,
while moving it upward and backward.
 Removing theTray Door
(See Fig.2)
1.Eject the disc tray.
(Rotate the screw B counter - clockwise if no supply)
2.Lift up the tray door in the indicated direction
Fig.1
CLASS 1
LASER PRODUCT
Right coverLeft cover
Top cover
Rear cover
Fig.2
B

TH-A35
1-7
Fig.3
Fig.4
Fig.5
 Removing the cabinet front
(See Fig.3)
[Caution] You must ensure theTRAY door isn't it's place
before you remove the panel front from body.
1.Unscrew the serew 2 C & 2 D.
2. Pull the panel front toward yourself while pressing 5
stoppers to disengage.
 Removing theTUNER and panel rear
(See Fig.4)
1.Unserew the screw H form mpeg board unit and unit
and main board unit.
2.Unserw the screw K form body.
3.Take the supply cord out of panel rear.
4. Remove teh panel rear with tuner .
< CHAS, MAIN ASSEMBLY >
 Removing the MPEG BOARD
(See Fig.5)
[Caution] Mpeg board may be taken out only when the
panel rear and Tunet have been taken away.
1.Pull the cable connetor mpeg board.
2.Unscrew the screw M.
3.Separate the mpeg board from main board
vertically.
D
C
STOPPER
STOPPER STOPPER STOPPER
STOPPER
C
D
M
CLASS 1
LASER PRODUCT
H
K

TH-A35
1-8
Removing the MAIN Board
( See Fig.6 & 7 )
[Caution] Main board may be taken out when the
mpeg board has been taken away.
1. Force the PCB spacer Q to exit the holes of main
board.
2.Unscrew the screw P.
3.Unscrew the screw R then you can remove the main
board with heat sink.
4.Untie or open connecters to power transformer,
PWB,AMP, DVD - mech.
Removing FAN
(See Fig.8)
1.Unscreew 3 screws R with HOLDER, pull
out connector from PWB, main.
2.Unscrew 2 screws S from HLDR.
Removing theThermal - Regifer
(See Fig.9)
1.Unscreew the screws though power IC and
thermal- HOLDER.
2.Pull wire of thermal - register from PWB main.
P
QFig. 6
Fig. 7
Fig. 9
Fig. 8
RS
PULL

TH-A35
1-9
Removing the CD mechanism base
assembly (See Fig.10)

Prior to performing the following procedure, remove
the cabinet front assembly.
1. Disconnect the harnesses from connector CN191
and CN192 on the main board and release them
from the cord stopper respectively.
2. Remove the four screws M attaching the
transformer assembly.
Removing PWB,AMP (See Fig.11)
1. Unscrew 4 screws L.
2. Pull out connecter from PWB, AMP.
Removing Power, frusformer(See Fig.11)
1. Unscrew 4 screws N
2. Untie wire connecter to PWB, MAIN.
Fig. 11
Fig. 10

TH-A35
1-10
<Front panel assembly>
Removing the front PWB & Led, PWB
(See Fig.12-13)

Prior to performing the following procedure, remove
the front panel assembly.
1. Remove the seven screws X and 3 screws
attaching the front panel board inside the front
panel assembly.
2. Push out KNOB, VOLUME through PWB, FR.
Fig. 13
Fig. 12

TH-A35
1-11
1. Pin layput
2. Block diagram
Description of major ICs
 STK402-950 ( U701 ) : 5 channels AF power amplifier.
¥~«‹„ˇ4200
(unit:mm)
3.6
(12.0)
2.0
16.5 21.0
32.0
27.34.0
23x2.0=46.0
0.5
5.5
0.4
2.9
8.5
124
78.0
70.0

TH-A35
1-12
2. PIN CONFIGURATION
WM8770 ( U1 ) : 8-channel code c & volume control
1.

TH-A35
1-13
1.Block Diagram
UPD78F0034A ( IC 401 ) : CPU

TH-A35
1-14
2.Outline of Function

TH-A35
1-15
1. BLOCK DIAGRAM
UPD 16315 ( IC904 ):VFD control ler / driver
Description of major ICs

TH-A35
1-16
2. Pin Layout ( AK4112BVF )
 AK4112 ( U17 ) : Digital audio receiver
1. BLOCK DIAGRAM

TH-A35
1-17
 M29W160DB ( U12 ) : 16M Flash memory
.Pim layout
DQ3
DQ9
DQ2
A6 DQ0
W
A3
RB
DQ6
A8
A9 DQ13
A17
A10 DQ14
A2
DQ12
DQ10
DQ15A±1
VCC
DQ4
DQ5
A7
DQ7
NC
NC
AI03844
M29W160DT
M29W160DB
12
1
13
24 25
36
37
48
DQ8
NC
A19
A1
A18
A4
A5
DQ1
DQ11
G
A12
A13
A16
A11
BYTE
A15
A14 VSS
E
A0
RP
VSS

TH-A35
1-18
 2a3020 ( IC 701 ): DC - DC Regulator
 LX171/LX1711 ( IC603 ) :
1.5V
Internal
Regulators
Osc llator
40 / 400 KHz
2
2.30/2.53V
0.7V 1uA
3
4
M2
10 ohm
(
VIN
8
SYNC
7
EN
5FB
6COMP
1.22V
Shutdown
Comparator
Frequency
Foldback
Comparator
Error Am pl f er
gm = 630uM/Volt
Lockout
Comparator
Current
Sense
Amp llfler
Current
Comparator
GND
Vsw
SB
1
0.7V
SV
CLK
S
R
Q
Q
Slope
Compensat on
SLEEP
VREF
V25
CN
PVDD
CP
P+
N+
P-
N-
FAOUT
FBK-
FBK+
VDD
IS-
CLOCK
RPWM
CPWM
EAOUT
EAIN
INAMPOUT
INPUT -
INPUT +
MUTE
UVLO
&
REFERENCE
OUTPUT
DRIVERS
&
LOGIC
FAULT
TIMER
5V
Reference 26
4
1
10
CLK
OSC
SYNC
+
-220mV
PVDD
MUX
MUTE
MUTE
7
14
13
9
11
8
6
5
28
27
25
15
17
FEEDBACK AMP
ERROR AMP
CURRENT SENSE
INPUT AMP
16
24
23
22
21
20
S
R
Q
Q
CLK
5V
Reference 18
Class-D mono power amplifier controller

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1-19
 IR2110 ( IC603,604 ): Low and nigh side driver
Functional Block Diagram
 MC 14053B ( U21 ): digitally - controlled analog swith
Pin layout
VB
SD
LIN
VDD
PULSE
GEN
RSQ
VSS
UV
DETECT
DELAY
HV
LEVEL
SHIFT
V
CC
PULSE
FILTER
UV
DETECT
V
DD
/V
CC
LEVEL
SHIFT
V
DD
/V
CC
LEVEL
SHIFT LO
V
S
COM
RSQR
S
RQ
HIN
HO
YI
Y0
Z1
Z0
INH
VEE
VDD
Y
X
X1
X0
A
B
C
VSS
Z

TH-A35
1-20
Wiring connection