JVC UX-H33 Service Manual

MB038200310

SERVICE MANUAL

MICRO COMPONENT SYSTEM

UX-H33

MICRO COMPONENT SYSTEM

Area Suffix

A ------------- Australia

TABLE OF CONTENTS

1 PRECAUTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3

2 SPECIFIC SERVICE INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6

3 DISASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7

4 ADJUSTMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-19

5 TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-23

COPYRIGHT © 2003 VICTOR COMPANY OF JAPAN, LIMITED

No.MB038

2003/10

SPECIFICATION

Amplifier Output Power 20 W (10 W + 10 W) at 4 Ω (10% THD)

Audio input sensitivity/Impedance (at 1 kHz) AUX 500 mV/48.75 kΩ
Speakers/Impedance 4 Ω

Tuner FM tuning range 87.50 MHz - 108.00 MHz

AM tuning range 522 kHz - 1 629 kHz

CD player Dynamic range 85 dB

Signal-to-noise ratio 90 dB
Wow and flutter Immeasurable

Cassette deck Frequency response Normal (type I) 50 Hz - 15 000 Hz

Wow and flutter 0.15% (WRMS)

Speaker Speaker units Full range 8.0 cm cone × 1

Impedance 4 Ω
Dimensions (approx.) 135 mm × 203 mm × 190 mm (W/H/D)
Mass (approx.) 1.7 kg each

General Power requirement AC IN 240 V , 50 Hz

DC IN 12 V, 4 A

Power consumption 35 W (at operation)

3.0 W (on standby)
Dimensions (approx.) 412 mm × 208 mm × 275 mm (W/H/D)
Mass (approx.) 6.5 kg

1-2 (No.MB038)

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.MB038)1-3

1.5 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.

1.5.1 Grounding to prevent damage by static electricity

Static electricity in the work area can destroy the optical pickup (laser dio de) in devices such as CD 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

1M

Conductive material
(conductive sheet) or iron palate

(3) Handling the optical pickup

• In order to maintain quality during transport and befo re installation, both sides o f the laser diode on the repla cement 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.

1.6 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) I t is not possible to adjust the semi-fixed resistor that adjusts the laser power. Do not turn it.

1.7 Attention when traverse unit is decomposed *Please refer to "Disassembly method" in the text for the CD pickup unit.

• Apply solder to the short land sections before th e flexible wire is disconnected from the connector CN601

on the CD servo board.

(If the flexible wire is disconnected without applying solder, the CD 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.

1-4 (No.MB038)

Flexible wire

Shorting round

Shorting round

CN601 on
mechanism
board

1.8 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.

!

Please use enough caution not to
see the beam directly or touch it
in case of an adjustment or operation
check.

REPRODUCTION AND POSITION OF LABEL and PRINT

WARNING LABEL and PRINT

Caution label

(No.MB038)1-5

SECTION 2

SPECIFIC SERVICE INSTRUCTIONS

This service manual does not describe SPECIFIC SERVICE INSTRUCTIONS.

1-6 (No.MB038)

SECTION 3

A

A

A

DISASSEMBLY

3.1 Main body

3.1.1 Removing the rear panel
(See Fig.1,2)

(1) From behind the body, remove the eight screws A attach-

ing the rear panel.

(2) Turing the body upside down, remove the two screws B at-

taching the rear panel, and remove.

A

Fig.1

Rear panel

BB

CC

Front panel assembly

Fig.2

(No.MB038)1-7

3.1.2 Removning the side panel (L) and (R)
(See Fig.2~5)

• Prior to performing the following procedure, remove the rear

panel.
(1) Turning the body upside down, remove the two screws C

attaching the front panel assembly.

(2) Turning the body initial position, open the CD door while

pressing the upper OPEN button.

(3) Moving the side panel (L) in the arrow direction, remove the

panel from the left side of the body.

(4) Moving the side panel (R) in the arrow direction, remove

the panel from the right side of the body.

Fig.3

Side panel (L)

1-8 (No.MB038)

Fig.4

Side panel (R)

Fig.5

3.1.3 Removing the CD player assembly

(See Fig.6,7)

• Prior to performing the following procedure, remove the rear

panel and the left and right side panels.
(1) Disconnect the card wires from the two connectors CN603

and CN604 on the CD servo control board.

(2) Remove the two screws D attaching the front panel assem-

bly on the both sides.

(3) Release the two joints a on the both sides of the front panel

assembly.

(4) Move the CD player assembly in the direction of the arrow.

CD player assembly

a

D

CD servo control board

CN604

CN603

Fig.6

CD player assembly

a

Fig.7

D

(No.MB038)1-9

3.1.4 Removing the power amplifier board and heat sink
(See Fig.8~10)

• Prior to performing the following procedure, remove the rear

panel, the left and right side panels, and the CD player assem­bly.
(1) Remove the five screws E and F attaching the heat sink.
(2) Disconnect the wire from connector CN901

supply board.

(3) Disconnect the card wire from connector CN305

power amplifier board.
(4) Remove the screw G attaching the power amplifier board.
(5) Disconnect the connector CN301

board, and release the two joints b.

REFERENCE:

Remove the screw F, then power amplifier board can be re­moved without removing heat sink.

on the power amplifier

on the power

on the

Heat sink

E

E

F

Fig.8

Power amplifier board

CN301

1-10 (No.MB038)

Power supply board

CN901

Fig.9

Power amplifier board

bb

G

Fig.10

CN305

3.1.5 Removing the tuner board
(See Fig.11)

• Prior to performing the following procedure, remove the rear

panel, the left and right side panels, and the CD player assem­bly.
(1) Remove the screw H attaching the tuner board from the

right side of the body.

(2) Disconnect the card wire from th e connector CN1

tuner board.

(3) Release the joint c, and remove the tuner board backward.

3.1.6 Removing the front panel assembly
(See Fig.12,13)

• Prior to performing the following procedure, remove the rear

panel the left and right side panels, the CD player assembly,
the power amplifier board.
(1) Disconnect the card wire from the connector CN714

LCD system CPU board.

(2) Release the joint d on the bottom of the front panel assem-

bly using a screwdriver, and remove the front panel assem­bly toward the front.

on the

on the

c

CN1

H

Tuner board

Fig.11

LCD system CPU board

CN714

Fig.12

d

Front panel assembly

Fig.13

(No.MB038)1-11

3.1.7 Remove the power transformer and power supply board

r

(See Fig.14,15)

• Prior to performing the following procedure, remove the rear
panel, the left and right side panels, the CD player assembly,
the power amplifier board and the tuner board.
(1) Remove the screw I attaching the jack holder and release

joint e, and then remove jack holder.

(2) Remove the four screws J attaching the power transformer

and power supply board.

e

Jack holder

I

Fig.14

J

Power supply board

Power transforme

J

Fig.15

1-12 (No.MB038)

3.1.8 Remove the cassette mechanism assembly
(See Fig.16,17)

• Prior to performing the followin g procedure, remove the front

panel assembly.
(1) Disconnect the card wire from the connector CN713

LCD system CPU board.

(2) Remove the four screws K and L attaching the cassette

mechanism assembly, and remove.

on the

Front panel assembly

CN713

LCD system CPU board

Fig.16

K

L

Cassette mechanism assembly

Fig.17

(No.MB038)1-13

3.1.9 Remove the LCD system CPU board
(See Fig.18)

(1) Disconnect the wire from the connector CN716

system CPU board.

(2) Release the two joints f and pull out the LCD system CPU

board.

on the LCD

f

CN716

3.1.10 Removing the operating switch board
(See Fig.19,20)

• Prior to performing the following procedure, remove the front

panel assembly, the cassette mechanism assembly and the
LCD system CPU board.
(1) Remove the two screws M attaching the operating switch

button.

(2) Remove the two screws N attaching the operating switch

board, and remove.

M

LCD system CPU board

Fig.18

Operating switch button

Fig.19

N

1-14 (No.MB038)

Operating switch board

Fig.20

3.2 Cassette mechanism assembly

3.2.1 Removing the Play/Record & Clear head

(See Fig.1~3)

(1) While moving the trigger arm on the right side of the he ad

mount in the direction of the arrow, turn the flywheel R
counterclockwise until the head mount comes ahead and
clicks.

(2) The head turn s counterclockwise as you turn the flywheel

R counterclockwise (See Fig.2 and 3).

(3) Disconnect the flexible wire from connector CN31

head amplifier & mechanism control board.
(4) Remove the spring from the back of the head.
(5) Loosen the azimuth screw for reversing attaching the head.
(6) Remove the head on the front sid e of the hea d mount.

on the

Cassette mechanism assembly

Fig.1

Head

Fly wheelR

Trigger armHead mount

Flexible wire

Fly wheel R

Fig.2

Azimuth screw

Head

for reversing

Spring

CN31

Head amplifer & mecha control board

Fig.3

(No.MB038)1-15

3.2.2 Removing the head amplifier & mechanism control board
(See Fig.4)

(1) Turn over the cassette mech anism assembly and remove

the three screws A attaching the head amplifier & mecha­nism control board.

(2) Disconnect the flexible wire fro m connector CN31

head amplifier & mechanism control board.

(3) Disconnect connector CN32

anism control board from connector CN1
board.REFERENCE: If necessary, unsolder the 4-pin wire
soldered to the main motor.

3.2.3 Removing the main motor
(See Fig.4~7)

(1) Remove the two screws B .
(2) Half raise the motor and remove the capstan belt from the

motor pulley.

ATTENTION:

Be careful to keep the capstan belt from grease. When reas­sembling, refer to Fig.6 and 7 for attaching the capstan belt.

Head amplifier & mecha control board

of the head amplifier & mech-

on the reel pulse

on the

Main motor assembly

Capstan belt

Fig.5

Main motor assembly

CN31

Flexible wire

A

AA

Fig.4

CN32

4pin wire

B

Main motor assembly

Motor pulley

Capstan belt

Fig.6

Main motor assembly

Fly wheel

1-16 (No.MB038)

Capstan belt

Motor pulley

Fig.7

3.2.4 Removing the flywheel

(See Fig.8, 9)

• Prior to performing the following pro cedure, remove the head

amplifier & mechanism control board and the main motor as­sembly.
(1) From the front side of the cassette mechanism, remove the

slit washers attaching the capstan shaft L and R. Pull out
the flywheels backward.

Fly wheel R Fly wheel L

Fig.8

Fly wheel R

Capstan shaft R Capstan shaft L

Slit washer

Fig.9

3.2.5 Removing the reel pulse board and solenoid

(See Fig.10)

• Prior to performing the following procedure, remove the head amplifier & mechanism control board .

(1) Remove the screw C.
(2) Release the tab a, b, c, d and e retaining the reel pulse board.
(3) Release the tab f and g attaching the solenoid on the reel pulse board.
(4) The reel pulse board and the solenoid come off.

Fly wheel L

bc

a

Solenoid

g

f

d

Reel pulse board

C

e

Fig.10

(No.MB038)1-17

3.2.6 Reattaching the Play/ Record & Clear head

r

r

(See Fig.11~13)

(1) Reattaching the head mount assembly.

a) Change front of the direction cover of the head

mount assembly to the left (Turn the head forward).

b) Fit the bosses O', P', Q', U' and V' on the head mount

assembly to the holes P and V, the slots O, U and Q
of the mechanism sub assembly (See Fig.11 to 13).

CAUTION:

To remove the head mount assembly, turn the direction
cover to the left to disengage the gear. If the gear can not
be disengaged easily, push up the boss Q' slightly and
raise the rear side of the head mounts slightly to return

the direction lever to the reversing side.
(2) Tighten the azimuth screw for reversing.
(3) Reattach the spring from the back of the Play/ Record &

Clear head.

(4) Connect the flexible wire to connector CN31

amplifier & mechanism control board.

on the head

U' Q'

Head mount assembly

Head mount assembly

O'

Fig.11

P'

P'

V'

V'

Direction cove

Spring

Flexible wire

V

O

P

Q

Head

Direction cove

U

Fig.12

Azimuth screw for reversing

Head mount

1-18 (No.MB038)

CN31

Fig.13

Head amplifier &

mechanism control board

SECTION 4

ADJUSTMENT

4.1 Measurement Instruments Required for Adjustment

(1) Low frequency oscillator

This oscillator should have a capacity to output 0dBs to

600Ω at an oscillation frequency of 50Hz-20kHz.
(2) Attenuator impedance : 600Ω
(3) Electronic voltmeter
(4) Distortion meter
(5) Frequency counter
(6) Wow & flutter meter
(7) Test tape

VT703L : Head azimuth

VT712 : Tape speed and running unevenness (3kHz)

VT724 : Reference level (1kHz)
(8) Blank tape

TYPE l : AC-225

TYPE ll : AC-514
(9) Torque gauge : For play and back tension

FWD(TW2111A), REV(TW2121a) and FF/REW(TW2231A)

(10) Test disc: CTS-1000

4.2 Measurement conditons

Power supply voltage AC240V~, 50Hz
Reference output Speaker : 0.775V/6Ω

Headphone : 0.077V/32Ω

Reference frequency and input level 1kHz, AUX : -8dBs
Measurement output terminal at Speaker J3002
Load resistance 4Ω

4.2.1 Radio Input signal

AM frequency 400Hz
AM modulation 30%
FM frequency 400Hz
FM frequency deviation 22.5kHz

4.2.2 Tuner section

Voltage applied to tuner +B : DC5.7V

VT : DC 12V
Reference measurement output 26.1mV(0.28V)/3Ω
Input positions AM : Standard loop antenna

FM : TP1 (hot) and TP2 (GND)

4.2.3 Standard measurement position of volume

Function switch to Tape
Beat cut switch to Cut
Super Bass/Active hyper Bass to OFF
Bass Treble to Center
Adjustment of main volume to reference output VOL : 0.775V

Precautions for measurement

(1) Apply 30pF and 33kΩ to the IF sweeper output side and

0.082µ F and 100kΩ in series to the sweeper input side.

(2) The IF sweeper output level should be made as low as

possible within the adjustable range.

(3) Since the IF sweeper is a fixe d device, there is no need

to adjust this sweeper.

(4) Since a ceramic oscillator is used, ther e is no need to

perform any MIX adjustment.

(5) Since a fixed coil is used, there i s no need to adjust the

FM tracking.

(6) The input and output earth systems are separated. In

case of simultaneously measuring the voltage in both of
the input and output systems with an electronic voltmeter
for two channels, therefore, the earth should be connect­ed particularly carefully.

(7) In the case of BTL connection amp., the minus terminal

of speaker is not for earthing. Therefore, be sure not to
connect any other earth terminal to this terminal. This
system is of an BTL system.

(8) For connecting a dummy resisto r when measuring the

output, use the wire with a greater code size.

(9) Whenever any mixed tape is used, use the band pass fil-

ter (DV-12).

(No.MB038)1-19

4.3 Cassette mechanism adjustment

Head azinuth
adjustment screw
(Forward side)

Mecha control board

Head azinuth
adjustment screw
(Reverse side)

SW1

SW2

Head azinuth
adjustment screw
(Forward side)

Head azinuth
adjustment screw
(Reverse side)

CN31

R/P head, Erase head

P1

D1

VR37

R371

CN1

FW100

SW5

Motor speed
VR37

BIAS adjust

VR31

C308

R327

R315

VR31

R313

Q302

C316

C319

R314

C121

C221

C314

L301

R104

Q305

C313

D340

C310

R304

R310

C107

L303

R102

R121

R221

R303

R335

R353

R339

R108

C113

R302

Q343

C103

C207

R301

C301

Q342

C105
C205

C304

R208

C106

R101

C104

R306

R106

Q344

CN34

C306

R344

R105

C102

R205

R110

Q345

R345

C307

R336

C340

C206

R346

R206

W1

R107

Q346

R305

C110

R210

C300

C341

R109

R372

Q372

C371

CN33

IC32

R116

C109

CN31

Q371

C101

C374

Q375

R376

R216

C376

R204

R201

C202

C204

C201

CN32

C203

R202

C210

R340

C331

R342

R347

Q347

SW6

R343

R341

IC33

IC1

D375

Q376

R338

R375

R337

C213

C342

C209

W1

R207

1-20 (No.MB038)

4.3.1 Mechanism section

Item Condition Measurement method Ref. value

Head azimuth Test tape

:VT703L (8kHz)
Output terminal
:Speaker out

Tape speed Test tap

:VT712 (3kHz)
Output terminal
:Speaker out or Headphone out

Item Condition Measurement method Ref. value

Tape speed
diviation at FWD/
REV

Wow & Flutter Test tape

Test tape
: VT712 (3kHz)
Output terminal
:Speaker out or Headphone out

: VT712 (3kHz)
Output terminal
:Speaker out or Headphone out

(1) Playback the test tape VT703L (8kHz).
(2) Adjust to maximu m output level by azi-

muth adjustment screw for forward side
and reverse side.

(3) This adjustment is adjust by adjustment

screw of forward side and adjustment
screw of reverse side.

Playback the test tape VT712 (3kHz) at end of
forward side,adjust to 2,940~3,90Hz indication
of frequency counter by VR37

Playback the test tape VT712 (3kHz) at end of
forward and reverse, tape speed deviation
should be less than 6.0Hz.

Playback the test tape VT712 (3kHz) at start of
forward and reverse, Wow & Flutter are should
be less than 0.25%(WRMS).

.

Adjustment

position

Maximum output Only adjust

at changed
head

2,940 ~ 3,090Hz VR37

Adjustment

position

Leass than

6.0Hz

Less than 0.25%

(WRMS)

VR31

4.3.2 Electrical adjustment

Item Condition Measurement method Ref. value

Recording BIAS
adjustment

R/P playback
frequency
response

• Forward or Reverse

•Test tape
: AC-514 TYPE ll
: AC-225 TYPE l

• Output termina
Recording head

• Reference frequency
: 1kHz / 10kHz
(Reference: -20dB)

•Test tape
: AC-514 TYPE ll

• Input terminal
: OSC IN

(1) Set the test tape(AC-514 TYPE ll and

AC-225 TYPE l), then make REC/
PAUSE condition.

(2) Connect 100Ω to recording head by se-

ries, then connect to VTVM for measure­ment the current.

(3) After setting, start the recording by re-

lease the PAUSE, in this time bias cur­rent adjust to next fig. by VR31
and VR32

4.0 µA (TYPE ll) and 4.20 µA (TYPE l).

(1) Set the test tape (AC-514 TYPE ), then

make REC/PAUSE condition.

(2) Release the PAUSE, then start recording

the 1kHz and 10kHz of reference fre­quency from oscillator.

(3) Playback the recorded position, 1kHz

and 10kHz output deviation should -1dB
2dB to readjust by VR31

VR32

for Rch.

for Rch.

for Lch

for Lch and

AC-225
: 4.20µA
AC-514
: 4.0µA

Output deviation
1kHz/10kHz
: -1dB ± 2dB

Adjustment

position

VR31

VR31

(No.MB038)1-21

4.3.3 Electrical response confirmation

Item Condition Measurement method Ref. value

Recording bias
current

Erase current (ref­erence value)

• Forward or Reverse

• Test tape
: TYPE ll (AC-514)

• Measurement terminal
: BIAS test point on printed
circuit board

• Forward or Reverse

• Rec condition
Test tape
: AC-514 TYPE ll
: AC-225 TYPE l

• Measurement terminal
Both side of Erase head

(1) Change BIAS1 and 2, confirm the fre-

quency should be change.

(2) Set the test tape (AC-514 TYPE ll), then

make REC/PAUSE condition.

(3) Confirm the frequency should 100Hz ±

6kHz at BIAS test point on printed circuit
board.

(1) Set the test tape (AC-514 TYPE ll and

AC-225 TYPE l), then make REC/
PAUSE condition.

(2) Release the PAUSE to REC condition,

connect 1W to ERASE head by series,
then confirm the erase current at both
side of erase head.

Adjustment

position

100 kHz ± 6 kHz

TYPE ll
: 120 mA
TYPE l
: 75 mA

1-22 (No.MB038)

TROUBLESHOOTING

5.1 Flow of functional operation until TOC read (CD)

Power ON

Power Key

SECTION 5

Slider turns REST
SW ON.

Automatic tuning
of TE offset

Check Point

Check that the voltage at the pin4

of CN601 is 0V (a moment)?

VREF

Tracking error waveform at TOC reading

pin 20 of
IC601(TE)

Approx

1.8V

Tracking
servo

Disc statas
to rotate

off statas

Automatic measurement
of TE amplitude and
automatic tuning of
TE balance

Approx.3sec

Tracking
servo
on statas

Disc to be
braked to stop

TOC reading
finishes

500mv/div
2ms/div

Fig.1

Laser ON

Detection of disc

Automatic tuning of
Foucus offset

Automatic measurement of
Focus A-curve amplitude

Disc is rotated

Focus servo ON
(Tracking servo ON)

Automatic measurement of
Tracking error amplitude

Automatic tuning of
Tracking error balance

Check that the voltage at the

pin2 of IC601 is 0V?

Confirm that the Focus error
S-cuve siganl at the pin23 of
IC601 is approx.2Vp-p

Confirm that the siganl from
pin22 IC603 is 0V as a
accelerated pulse during
approx.400ms.

Confirm the waveform of
the Tracking error signal
at the pin20 of IC601
(See fig-1)

Automatic tuning of
Focus error balance

Automatic tuning of
Focus error gain

Automatic tuning of
Tracking error gain

TOC reading

Play a disc

Confirm the eys-pattern
at the lead of TP1

(No.MB038)1-23

5.2 Maintenance of laser pickup (CD)

(1) Cleaning the pick up lens

Before you replace the pick up, please try to clean the lens
with a alcohol soaked cotton swab.

(2) Life of the laser diode

When the life of the laser diode has expired, the following
symptoms will appear.

• The level of RF output (EFM output : ampli tude of eye
pattern) will below.

5.3 Replacement of laser pickup (CD)

Turn off the power switch and, disconnect the
power cord from the ac outlet.

Replace the pickup with a normal one.(Refer
to "Pickup Removal" on the previous page)

Is the level of

RFOUT under

NO

Replace it.

1.25V 0.22Vp-p?

YES

O.K

(3) Semi-fixed resistor on the APC PC board

The semi-fixed resistor on the APC printed circuit board
which is attached to the pickup is used to adjust the laser
power. Since this adjustment should be performed to
match the characteristics of the whole optical block, do not
touch the semi-fixed resistor.
If the laser power is lower than the specified value, the la­ser diode is almost worn out, and the laser pickup should
be replaced.
If the semi-fixed resistor is adjusted while the pickup is
functioning normally, the laser pickup may be damaged
due to excessive current.

Plug the power cord in, and turn the power on.
At this time, check that the laser emits for
about 3seconds and the objective lens moves
up and down.
Note: Do not observe the laser beam directly.

Play a disc.

Check the eye-pattern at TP1.

Finish.

1-24 (No.MB038)

(No.MB038)1-25

VICTOR COMPANY OF JAPAN, LIMITED

AV & MULTIMEDIA COMPANY AUDIO/VIDEO SYSTEMS CATEGORY 10-1,1chome,Ohwatari-machi,Maebashi-city,371-8543,Japan

(No.MB038)

Printed in Japan

WPC