Zenith XBV243 series User manual

SERVICE MANUAL

Product Type: VCR DVD Combo

Chassis: D35E Combo

Manual Series: VR168

Manual Part #: 923-03485

Model Line: E

Product Year: 2002

General Info ................................................. 1

Service Menu ................................................ 2

Servicing ..................................................... 3

Parts List ..................................................... 4

Diagrams ...................................................... 5

Schematics ................................................... 6

Published March 2002

by Technical Publications

Zenith Electronics Corporation

201 James Record Road

Huntsville, Alabama 35824-1513

Copyright  2002 by Zenith Electronics Corporation

Model Series:

CONTENTS

XBV243

VR168 - 923-03485 D35E COMBO - SAFETY

PRODUCT SAFETY SERVICING GUIDELINES FOR AUDIO-VIDEO PRODUCTS

i

IMPORTANT SAFETY NOTICE

This manual was prepared for use only by properly trained audio-video service

technicians.

When servicing this product, under no circumstances should the original

design be modified or altered without permission from Zenith Electronics

Corporation. All components should be replaced only with types identical to

those in the original circuit and their physical location, wiring and lead dress

must conform to original layout upon completion of repairs.

Special components are also used to prevent x-radiation, shock and fire hazard.

These components are indicated by the letter “x” included in their component

designators and are required to maintain safe performance. No deviations are

allowed without prior approval by Zenith Electronics Corporation.

Circuit diagrams may occasionally differ from the actual circuit used. This way,

implementation of the latest safety and performance improvement changes into

the set is not delayed until the new service literature is printed.

CAUTION: Do not attempt to modify this product in any way. Never perform

customized installations without manufacturer’s approval. Unauthorized

modifications will not only void the warranty, but may lead to property damage

or user injury.

Service work should be performed only after you are thoroughly familiar with

these safety checks and servicing guidelines.

GRAPHIC SYMBOLS

The exclamation point within an equilateral triangle is intended

to alert the service personnel to important safety information in

the service literature.

The lightning flash with arrowhead symbol within an equilateral

triangle is intended to alert the service personnel to the presence

of noninsulated “dangerous voltage” that may be of sufficient

magnitude to constitute a risk of electric shock.

The pictorial representation of a fuse and its rating within an

equilateral triangle is intended to convey to the service personnel

the following fuse replacement caution notice:

CAUTION: FOR CONTINUED PROTECTION AGAINST RISK OF FIRE,

REPLACE ALL FUSES WITH THE SAME TYPE AND RATING AS MARKED

NEAR EACH FUSE.

SERVICE INFORMATION

While servicing, use an isolation transformer for protection from AC line shock.

After the original service problem has been corrected, make a check of the

following:

FIRE AND SHOCK HAZARD

1. Be sure that all components are positioned to avoid a possibility of

adjacent component shorts. This is especially important on items trans-

ported to and from the repair shop.

2. Verify that all protective devices such as insulators, barriers, covers,

shields, strain reliefs, power supply cords, and other hardware have been

reinstalled per the original design. Be sure that the safety purpose of the

polarized line plug has not been defeated.

3. Soldering must be inspected to discover possible cold solder joints, solder

splashes, or sharp solder points. Be certain to remove all loose foreign

particles.

4. Check for physical evidence of damage or deterioration to parts and compo-

nents, for frayed leads or damaged insulation (including the AC cord), and

replace if necessary.

5. No lead or component should touch a high current device or a resistor

rated at 1 watt or more. Lead tension around protruding metal surfaces

must be avoided.

6. After reassembly of the set, always perform an AC leakage test on all exposed

metallic parts of the cabinet (the channel selector knobs, antenna terminals,

handle and screws) to be sure that set is safe to operate without danger of

electrical shock. DO NOT USE A LINE ISOLATION TRANSFORMER DURING THIS

TEST. Use an AC voltmeter having 5000 ohms per volt or more sensitivity in

the following manner: Connect a 1500 ohm, 10 watt resistor, paralleled by

a .15 mfd 150V AC type capacitor between a known good earth ground

water pipe, conduit, etc.) and the exposed metallic parts, one at a time.

Measure the AC voltage across the combination of 1500 ohm resistor and

.15 mfd capacitor. Reverse the AC plug by using a non-polarized adaptor

and repeat AC voltage measurements for each exposed metallic part. Voltage

measured must not exceed 0.75 volts RMS. This corresponds to 0.5 milliamp

AC. Any value exceeding this limit constitutes a potential shock hazard and

must be corrected immediately.

X-RADIATION

1. Be sure procedures and instructions to all service personnel cover the

subject of x-radiation. The only potential source of x-rays in current TV

receivers is the picture tube. However, this tube does not emit x-rays when

the HV is at the factory-specified level. The proper value is given in the

applicable schematic. Operation at higher voltages may cause a failure of

the picture tube or high-voltage supply and, under certain circumstances

may produce radiation in excess of desirable levels.

2. Only factory-specified CRT anode connectors must be used.

3. It is essential that the service personnel have available an accurate and

reliable high-voltage meter.

4. When the high-voltage circuitry is operating properly, there is no possibility

of an x-radiation problem. Every time a chassis is serviced, the brightness

should be run up and down while monitoring the high voltage with a

meter, to be certain that the high voltage does not exceed the specified

value and that it is regulating correctly.

5. When troubleshooting and making test measurements in a product with a

problem of excessively high voltage, avoid being unnecessarily close to

the picture tube and the high voltage power supply. Do not operate the

product longer than necessary to locate the cause of excessive voltage.

6. Refer to the CRT Anode High Voltage Measurement and Shutdown Adjustment

procedures described in the appropriate text (where used).

IMPLOSION

1. All direct view picture tubes are equipped with an integral implosion

protection system; take care to avoid damage during installation.

2. Use only the recommended factory replacement tubes.

TIPS ON PROPER INSTALLATION

1. Never install any receiver in a closed-in recess, cubbyhole, or closely

fitting shelf space over, or close to, a heat duct, or in the path of heated

air flow.

2. Avoid conditions of high humidity such as: outdoor patio installations

where dew is a factor, near steam radiators where steam leakage is a factor,

etc.

3. Avoid placement where draperies may obstruct venting. The customer

should also avoid the use of decorative scarves or other coverings that

might obstruct ventilation.

4. Wall- and shelf-mounted installations using a commercial mounting kit

must follow the factory-approved mounting instructions. A product mounted

to a shelf or platform must retain its original feet (or the equivalent

thickness in spacers) to provide adequate air flow across the bottom. Bolts

or screws used for fasteners must not touch any parts or wiring. Perform

leakage tests on customized installations.

5. Caution customers against mounting a product on a sloping shelf or in a

tilted position, unless the receiver is properly secured.

6. A product on a roll-about cart should be stable in its mounting to the cart.

Caution the customer on the hazards of trying to roll a cart with small

casters across thresholds or deep pile carpets.

7. Caution customers against using a cart or stand that has not been listed

by Underwriters Laboratories, Inc. for use with its specific model of

television receiver or generically approved for use with TVs of the same or

larger screen size.

8. Caution customers against using extension cords. Explain that a forest of

extensions, sprouting from a single outlet, can lead to disastrous

consequences to home and family.

A

.C. Voltmeter

1500 OHM

10 WATT

Place this probe

on each expose

d

metal part.

Good Earth Ground

such as the Water

Pipe, Conduit, etc.

0.15uF

TABLE OF CONTENTS

VR168 - 923-03485 D35E COMBO - TOC

SECTION 1 SUMMARY 1-1

SPECIFICATIONS ..........................................1-1

KEY TO ABBREVIATIONS ................................ 1-2

SERVICING PRECAUTIONS .............................. 1-3

PACKAGE CONTENTS .....................................1-4

SECTION 2 CHASSIS 2-1

CABINET .................................................... 2-1

EXPLODED DIAGRAM ..................................... 2-1

SELF DIAGNOSTICS .......................................2-2

CABINET DISASSEMBLY ................................. 2-3

CIRCUIT BOARD DISASSEMBLY ........................2-4

SECTION 3 ELECTRICAL 3-1

DVD TROUBLESHOOTING ................................ 3-1

VCR TROUBLESHOOTING .............................. 3-17

SECTION 4 MECHANICAL 4-1

VCR DECK MECHANISM .................................. 4-1

VCR ALIGNMENT ........................................ 4-13

MAINTENANCE/INSPECTION PROCEDURE ......... 4-19

VCR MECHANISM TROUBLESHOOTING ............. 4-23

DVD DECK MECHANISM ............................... 4-29

MECHANISM DISASSEMBLY........................... 4-30

DECK MECHANISM ADJUSTMENT ................... 4-32

SECTION 5 PARTS 5-1

COMPONENT PARTS .......................................... 5-2

TOC-1

SECTION 6 DIAGRAMS 6-1

EXPLODED VIEW ........................................... 6-1

VCR EXPLODED VIEW .....................................6-2

DVD EXPLODED VIEW .....................................6-3

MAIN BLOCK DIAGRAM .................................. 6-4

POWER BLOCK DIAGRAM ................................6-5

TUNER-IF BLOCK DIAGRAM............................. 6-6

Y/C BLOCK DIAGRAM .....................................6-7

AUDIO BLOCK DIAGRAM ................................. 6-8

HIFI BLOCK DIAGRAM ................................... 6-9

SYSTEM BLOCK DIAGRAM ............................. 6-10

SECTION 7 SCHEMATICS 7-1

POWER SUPPLY CIRCUIT ................................7-1

TUNER/IF CIRCUIT .......................................7-2

AV CIRCUIT .................................................7-3

HIFI CIRCUIT .............................................. 7-4

SYSTEM CIRCUIT .......................................... 7-5

DVD CIRCUIT ............................................... 7-6

DRIVE RF CIRCUIT ........................................ 7-7

MPEG CIRCUIT .............................................7-8

AUDIO CIRCUIT............................................ 7-9

MICRO CIRCUIT.......................................... 7-10

JACKPACK CIRCUIT ..................................... 7-11

VCR PCB LAYOUT ........................................ 7-12

DVD PCB LAYOUT TOP.................................. 7-13

DVD PCB LAYOUT BOTTOM ............................ 7-14

OTHER PCB LAYOUTS ................................... 7-15

WAVEFORMS .............................................. 7-16

- TOC-2 -

VR168 - 923-03485 1-1 D35E COMBO - SUMMARY

SUMMARY

SPECIFICATIONS

DVD PART

Power supply ........................................ AC 120 V, 60 Hz

Power .................................................. 23 W

Mass .................................................... 3.0kg(6.6lbs)

External dimensions .............................. 430 x 88 x 247 (W x H x D)

Signal system ....................................... PAL 625/50, NTSC 525/60

Laser ................................................... Semiconductor laser, wavelength 650nm

Frequency range ................................... (digital audio) 4 Hz to 20 kHz

Signal-to-noise ratio ............................. (digital audio) More than 100 dB (EIAJ)

Audio dynamic range ............................. (digital audio) More than 95 dB (EIAJ)

Harmonic distortion .............................. (digital audio) 0.008%

Wow and flutter .................................... Below measurable level (less than +0.001% (W.PEAK) (EIAJ)

Operating Temperature ........................... 5°C (41°F) to 35°C (95°F)

OUTPUTS

Video outputs ...................................... 1.0V (p-p), 75., negative sync., RCA jack x 1

S video outputs .................................... (Y) 1.0V (p-p), 75., negative sync.,Mini DIN 4-pin x 1

(C)0.3V(p-p), 75.

Component video .................................. output (Y) 1.0 V (p-p), 75 ., negative sync., RCA jack x 1

(Pb)/(Pr) 0.7 V (p-p), 75 .

Audio output ....................................... (digital audio) 0.5V (p-p), 75., RCA jack X 1

Audio output ....................................... (optical audio) Optical connector x 1

Audio output ....................................... (analog audio) 2.0Vrms (1kHz,0dB), RCA jack (L,R) x 1

VHS PART

Video Head System ................................ Double azimuth 4 heads, helical scanning

RF Modulator........................................ UHF 28-68 (Adjustable)

Tape format .......................................... Tape width 12.7 mm (0.5 inch)

Timer ................................................... 24 hours display type

*Designs and specifications are subject to change without notice.

*Weight and dimensions shown are approximate.

section 1 SUMMARY

VR168 - 923-03485 1-2 D35E COMBO - SUMMARY

SUMMARY

A

AC

Alternating Current

ACC

Automatic Color Control

ADJ

Adjust

A/E

Audio Erase

AFC

Automatic Frequency Control

AFT

Automatic Fine Tuning

AGC Automatic Gain Control

ALC

Automatic Level Control

AM

Amplitude Modulation

AMP

Amplifier

ANT

Antenna

APC

Automatic Phase Control

ASS’Y

Assembly

AUD

Audio

AUTO

Automatic

AUX

Auxiliary

B

Base

BPF

Bandpass Filter

BW or B/W

Black and White

C

Capacitor, Chroma, Collector

CAN

Cancel

CAP

Capstan

CATV

Cable Television

CBA

Circuit Board Assembly

CCD

Charge Coupled Device

CFG

Capstan Frequency Generator

CH

Channel

CHROMA

Chrominance

CLK

Clock

CNR

Chroma Noise Redution

COMB

Combination

Comb Filter

COMP

Comparator

Composite

Compensation

CONV

Converter

CS

Chip Select

CST

Cassette

CTL

Control

CUR

Current

CYL

Cylinder

D

Drum, Digital, Diode, Drain

dB

Decibel

DC

Direct Current

DEMOD

Demodulator

DET

Detector

DEV

Deviation

DHP

Double High Pass

DIGITRON

Digital Display Tube

DL

Delay line

DOC

Drop Out Compensator

D/V

Dummy Vertical

E

Emitter

EE

Electric to Electric

EMP

Emphasis

EP

Extended Play

EQ

Equalizer

ES

Electrostatically Sensitive

F

Fuse

FB

Feed Back

FBC

Feed Back Clamp

FE

Full Erase

FF

Fast Forward

FG

Frequency Generator

FL

Filter

FM

Frequency Modulation

F/R

Front/Rear

FS

Frequency Synthesizer

FSC

Subcarrier Frequency

F/V

Frequency Voltage

FWD

Forward

G

GEN

Generator

GND

Ground

H

High, Horizontal

Hz

Hertz

I

IC

Integrated Circuit

IF

Intermediate Frequency

INS

Insert

I/O

Input/Output

L

Low, Left, Coil

LD

LED

LECHA

Letter Character

LP

Long Play

LPF

Low Pass Filter

M

MAX

Maximum

MD

Modulator

MIC

Microphone

MIN

Minimum

MIX

Mixer, Mixing

MM

Monostable, Multivibrator

MMV

Mono Multi Vibrator

MOD

Modulation, Modulator

MODEM

Modulator-Demodulator

N

NR

Noise Reduction

O

OSC

Oscillator

OSD

On Screen Display

P

PB

Playback

PCB

Printed Circuit Board

PG

Pulse Generator

PLL

Phase Locked Loop

P. P

Peak-to-Peak

PRE-AMP

Preamplifier

PS

Phase Shift

PWM

Pulse Width Modulation

Q

Transistor

QH

Quasi Horizontal

QSR

Quick Setting Record

QTR

Quick Timer Record

QV

Quasi Vertical

R

Resistor, Right

RE(or RC)

Remocon, Receiver

REC

Recording

REF

Reference

REG

Regulated, Regulator

REMOCON

Remote Control(unit)

REV

Reverse

REW

Rewind

RF

Radio Frequency

R/P

Record/Playback

RTC

Reel Time Counter

S

Serial

SH

Shift

SHARP

Sharpness

SIF

Sound Intermediate Frequency

SLD

Side Locking

S/N

Signal to Noise Ratio

SP

Standard Play

SUB

Subtract, Subcarrier

SW or S/W

Switch

SYNC

Synchronization

SYSCON

System Control

T

Coil

TP

Test Point

TR

Transistor

TRK

Tracking

TRANS

Transformer

TU

Tuner, Take-up

U

UHF

Ultra High Frequency

UNREG

Unregulated

V

Volt, Vertical

VA

Always Voltage

VCO

Voltage Controlled Oscillator

VGC

Voltage Gain Control

VHF

Very High Frequency

VISS

VHS Index Search

VR

Variable Resistor or Volume

V-SYNC

Vertical Synchronization

VTG

Voltage

VV

Voltage to Voltage

VXO

Voltage X-tal Oscillator

W

Watt

WHT

White

W.O

With out

X

X-TAL

Crystal

Y

Y/C

Luminance/Chrominance

YNR

Luminance Noise Reduction

Z

ZD

Zener Diode

KEY TO ABBREVIATIONS

VR168 - 923-03485 1-3 D35E COMBO - SUMMARY

SUMMARY

SERVICING PRECAUTIONS

CAUTION: Before servicing the product covered by this

service data and its supplements and addends, read and

follow the SAFETY PRECAUTIONS.

NOTE: if unforeseen circumstances create conflict between

the following servicing precautions and any of the

safety precautions in this publication, always follow

the safety precautions.

GENERAL SERVICING PRECAUTIONS

1. Always unplug the product AC power cord from the

AC power source before:

(1) Removing or reinstalling any component, circuit

board, module, or any other assembly.

(2) Disconnecting or reconnecting any internal elec-

trical plug or other electrical connection.

(3) Connecting a test substitute in parallel with an

electrolytic capacitor.

CAUTION: A wrong part substitution or incorrect polarity

installation of electrolytic capacitors may result in

an explosion hazard.

2. Do not spray chemicals on or near this product or

any of its assemblies.

3. Unless specified otherwise in this service data, clean

electrical contacts by applying an appropriate con-

tact cleaning solution to the contacts with a pipe

cleaner, cotton-tipped swab, or comparable soft ap-

plicator. Unless specified otherwise in this service

data, lubrication of contacts is not required.

4. Do not defeat any plug/socket B+ voltage interlocks

with which instruments covered by this service

manual might be equipped.

5. Do not apply AC power to this product and/or any of

its electrical assemblies unless all solid-state device

heat sinks are correctly installed.

6. Always connect the test instrument ground lead to

the appropriate ground before connecting the test

instrument positive lead. Always remove the test in-

strument ground lead last.

INSULATION CHECKING PROCEDURE

Disconnect the attachment plug from the AC outlet and

turn the power on. Connect an insulation resistance meter

(500V) to the blades of the attachment plug. The

insulation resistance between each blade of the

attachment plug and accessible conductive parts should

be more than 1Mohm. Accessible conductive parts

include metal panels, input terminals, earphone jacks,

etc.

ELECTROSTATICALLY SENSITIVE (ES) DEVICES

Some semiconductor (solid state) devices can be

damaged easily by static electricity. Such components

commonly are called Electrostatically Sensitive (ES)

Devices. Examples of typical ES devices are integrated

circuits and some field effect transistors and

semiconductor chip components. The following

techniques should be used to help reduce the incidence

of component damage caused by static electricity.

1. Immediately before handling any semiconductor com-

ponent or semiconductor-equipped assembly, drain

off any electrostatic charge on your body by touch-

ing a known earth ground. Alternatively, obtain and

wear a commercially available discharging wrist strap

device, which should be removed for potential shock

reasons prior to applying power to the unit under

test.

2. After removing an electrical assembly equipped with

ES devices, place the assembly on a conductive sur-

face such as aluminum foil, to prevent electrostatic

charge buildup or exposure of the assembly.

3. Use only a grounded-tip soldering iron to solder or

unsolder ES devices.

4. Use only an anti-static solder removal device. Some

solder removal devices not classified as “anti-static”

can generate electrical charges sufficient to damage

ES devices.

5. Do not use freon-propelled chemicals. These can gen-

erate an electrical charge sufficient to damage ES

devices.

6. Do not remove a replacement ES device from its pro-

tective package until immediately before you are

ready to install it. (Most replacement ES devices are

packaged with leads electrically shorted together by

conductive foam, aluminum foil, or comparable con-

ductive material).

7. Immediately before removing the protective mate-

rial from the leads of a replacement ES device, touch

the protective material to the chassis or circuit as-

sembly into which the device will be installed.

Caution: Be sure no power is applied to the chassis or circuit,

and observe all other safety precautions.

8. Minimize bodily motions when handling unpackaged

replacement ES devices. (Normal harmless motion such

as the brushing together of your clothes fabric or

the lifting of your foot from a carpeted floor can

generate static electricity sufficient to damage an

ES device.)

VR168 - 923-03485 1-4 D35E COMBO - SUMMARY

SUMMARY

PACKAGE CONTENTS

BATTERY

PACKIN G SH EET

PACK ING

OPTIONAL PARTS

OWNER'S MANUAL

RF CABLE

CABLE SET ASS'Y

REMOCON

BOX CARTON

PACKING

PHONO CORD 1WAY

PHONO CORD 2WAY

VR168 - 923-03485 2-1 D35E COMBO - CHASSIS

CHASSIS

CABINET

FRONT

DISPLAY

BACK

section 2 CHASSIS

EXPLODED DIAGRAM

See page 6-1 for a detailed exploded view.

VCD

AB

DVD

ST

ALL MP3

-R W

BIL PR

SAP CH

AM

SP

LP

EP

DVD indicator

CD REC indicator

PROGRAM indicator

Repeat playback

mode indicators

Chapter/Track number indicator

Video CD indicator

A

ng

l

e

i

co

n

i

n

di

cator

Total playing time/elapsed time indicator

s

Title number indicator

Stereo indicator

VR168 - 923-03485 2-2 D35E COMBO - CHASSIS

CHASSIS

SELF DIAGNOSTICS

SELF DIAGNOSTIC OVERVIEW

Provides service personnel a convenient service aid by a

visual display of error codes generated by the

microcomputer and displayed on the digitron.

OPERATIONAL PROCEDURE

With the remote control, press and hold the “MENU” key

until the word MENU appears in the display. Then press

4, 3, 2, 1 and then “ENTER”. The self diagnostic procedure

will sequence through the 8 step procedure. If an error

is detected, a code number will flash approximately 5

times and then return to its initial mode of operation.

NOTES

1. Error codes will not be stored. The program must be

re-initialized as described in the preceding step.

2. Pin numbers refer to IC501 microcomputer, unless

otherwise stated.

DISPLAY

“D1”

“D2”

“D3”

“D4”

“D5”

“D6”

“D7”

“F1”

•Tape Loading

Error

•Tape Loading

Error

•CST Loading

Error

•CST Loading

Error

•DRUM Motor

Error

•Reel Rotational

Error

•Capstan Motor

Error

•Tuner Signal

Input

•Mode SW

Pos. S1, S2, S3, S4

Pins: 25, 24, 23, 22

•Load Motor

Pins: 60 (+)

Pins: 59 (-)

•Mode SW

Pos. S1, S2, S3, S4

Pins: 25, 24, 23, 22

•Load Motor

Pins: 60

•Mode SW

Pos. S1, S2, S3, S4

Pins: 25, 24, 23, 22

•Load Motor

Pins: 60

•Mode SW

Pos. S1, S2, S3, S4

Pins: 25, 24, 23, 22

•Load Motor

Pins: 60

•Head SW(30Hz)

Pulses Pin18

•Supply Take-up Reel

Pulses, Pins 79, 80

•Capstan FG Pulses

•CVin Pin 56

•Mode SW Position not

changed within 6 seconds

after cassette loading

attempt.

•Mode SW Position not

changed within 6 seconds

after cassette loading

attempt.

•Mode SW Position not

changed within 6 sec-

onds after cassette

loading attempt.

•CST SW must be activat-

ed within 3 seconds, oth-

erwise unit shut down will

occur.

•Drum Motor (Slow Start)

•Motor must be up to

speed within 3 seconds

of operation

•CFG Signal present, but

take-up pulses are mis-

sing.

(Capstan motor running)

•No CFG Signal

•Composite Sync not

detected, RF or Video

Signal loss.

•Loading motor,

mech problems,

gears, timing

•Mode SW Position

•Mode SW Contacts

•CST SW or

Connector Contacts

•Drum Motor and

Control Circuits

•Capstan belt

•Idler and reel gears

damaged

•ST/U Sensors

•Capstan control ckt.

•Motor assy.

•IC501 Ckt.

•Loss of C-sync

Tuner Line

Video Path

DESCRIPTION INPUT SIGNAL CIRCUIT STATUS SERVICE POINTS

VCR should be in PB mode for D5, D6 and D7. Stop mode for F1, cassette loading D3, D4 and tape loading D1 and D2.

VR168 - 923-03485 2-3 D35E COMBO - CHASSIS

CHASSIS

CABINET DISASSEMBLY

CAUTION BEFORE SERVICING

Electronic parts are susceptible to static electricity and

may easily be damaged. Follow proper grounding

procedures.

Many screws are used inside the unit. To prevent missing,

dropping, etc. of the screws, always use a magnetized

screw driver in servicing. Several kinds of screws are used

and some of them need special cautions. That is, take

care of the tapping screws securing molded parts and

fine pitch screws used to secure metal parts. If they are

used improperly, the screw holes will be easily damaged

and the parts can not be fixed.

CABINET DISASSEMBLY

TOP CASE

1. Remove 7 screws (A). (See Fig. 2-1)

2. Pull the top case back and up, in the direction of

the arrow, to disengage it from the front panel.

Fig. 2-1

TRAY DOOR

1. Eject the disc tray.

2. Lift up the tray door in the direction of the arrow.

Fig. 2-2

FRONT PANEL

1. Eject the disc tray. (See Fig. 2-2)

2. Remove the tray door. (See Fig. 2-2)

3. Depress the 7 embossed tabs (see fig. 2-3) and

remove the Front panel.

Fig. 2-3

Tab

Tabs

VR168 - 923-03485 2-4 D35E COMBO - CHASSIS

CHASSIS

CIRCUIT BOARD DISASSEMBLY

Note: Before removing the main circuit board, be sure

to short circuit the laser diode output land. After

replacing the main circuit board, open the land after

inserting the flexible connector.

MAIN CIRCUIT BOARD AND INTERFACE BOARD

1. Remove the top case. (See Fig. 2-1)

2. Remove 14 screws (B).

3. Remove the Deck from the Main Circuit Board.

4. Remove the Main Circuit Board from the Interface

Board.

5. Remove 2 screws (C).

6. Remove the Interface Board from the chassis.

Fig. 2-4

DIGITRON AND KEY CIRCUIT BOARD

1. Remove the front panel. (See Fig. 2-3)

2. Release 3 screws (D), and remove the digitron cir-

cuit board.

Fig. 2-5

VR168 - 923-03485 3-1 D35E COMBO - ELECTRICAL

ELECTRICAL

TROUBLESHOOTING

SECTION 3 Electrical

NO

N O

YES

N O

NO

YES

NO

YES

(3) No 5.2V (SYS/Hi-Fi/TUNER)

NO 5.3VA.

Is F101 normal?

Is R101

normal?

Is Bd101

normal?

Is Vcc (8.5~21V)

supplied to IC101 Pin7?

Is the D112 normal?

Is there about 2.5V

at the IC102 Vref?

Is D110 normal?

Check the Main PCB

5.3VA/5.0V Line short?

Replace F101.

Replace

BD101.

Replace R101.

Is D102

normal?

Check or Replace

D102.

Replace D112.

Replace IC102.

Replace the D110.

NO 12VA.

Check or Replace

D110.

Is the Vcc (13V) supplied to (+)

terminal in D115 and D117?

Check or Replace

the Motor Vcc.

Is the Vcc (12V) supplied to (-)

terminal in D115 and D117?

Replace D115,

NO 5.2VA.

5.3VA Line Check.

Is 5.3VA put into

Q116 Emitter?

Is about 5V put into

Q116 Base?

Is Q115 Base

“H”?

Check the Power

Control.

Check or Replace Q115,

R160, R161, R162, D122.

Check or Replace

Q115/Q116

1. Power(SMPS) CIRCUI

T

(1) No 5.3VA (SYS/Hi-Fi/TUNER)

(2) No 12VA (TO CAP, DRUM MOTOR)

VR168 - 923-03485 3-2 D35E COMBO - ELECTRICAL

ELECTRICAL

NO

YES

NO

YES

N O

YES

NO

YES

Check or Replace

Q115, R157, R158,

R159, D121.

NO 5V.

(4) No 5V (TO DVD)

Is 5.3VA present on

Q113 Emitter?

Check or Replace

Q113/Q115

Is about 5V present on

Q113 Base?

Is the Q115 Base

“H”?

No 33V.

Check the Power

Control.

Is Q115 Base “H”?

Check or Replace

Q114, R154, R155.

(6) No 33V (TUNER)

No REG 12V.

Check or Replace

D110.

Is 13V present on

Q112 Collector?

Is 33V present on

Q112 Base?

Check 33V Line.

Check or Replace Q112,

ZD103, R153, C151.

(7) No REG 12V

5.3VA Line Check.

(5) No REG 5V (AVCP)

Check the Power

Control.

5.3VA Line Check.

No REG 5V.

Is 5.3VA present on

Q117 Collector?

Check or Replace Q117,

R167, ZD105, C162.

Is 33V present on

Q117 Base?

Check 33V Line.

TROUBLESHOOTING (CONTINUED)

VR168 - 923-03485 3-3 D35E COMBO - ELECTRICAL

ELECTRICAL

No -29VA.

YES

(

8

)

NO

YES

(9) No 8VA

No 3.3V

YES

(10) No 3.3VA

N O

YES

NO

No -29VA.

Check or Replace

D108.

Is Vcc (4V) supplied

to IC103 Pin1?

Is the Q115 Base

“H”?

Check or Replace

IC103, R156, C153.

Check or Replace

D111.

Check the Power

Control.

NO 8VA.

Check or Replace

D110.

Is Vcc (13V) supplied to

(+) terminal in D114?

Is Vcc (12V) supplied

to IC106 Pin1?

Check or Replace

D114.

Check the Power

Control.

Check or Replace

IC106, R170, C154.

Is Q115 Base

“H”?

NO 2.5VA.

Is Vcc (4V) supplied

to IC104 Pin1?

Is the Q115 Base

“H”?

Is Vcc (3.3V) supplied

to IC104 Pin2?

Check or Replace

D119, C159.

Check or Replace

D111.

Check the Power

Control.

Check or Replace

Ic104.

(11) No 2.5V

TROUBLESHOOTING (CONTINUED)

VR168 - 923-03485 3-4 D35E COMBO - ELECTRICAL

ELECTRICAL

TROUBLESHOOTING (CONTINUED)

YES

NO

YES

NO

N

O

N

O

NO

NO NO

YES

YES YES

2. SYSTEM/KEY CIRCUIT

(1) AUTO STOP

Auto Stop

Does the SW30 waveform

appear at IC501

Pin24?

Do the T-UP Reel Pulses

appear at IC501 Pin4?

Replace Ic501.

(2) The unstable loading of a Cassette tape

Is 12V applied to

PMC01 Pin8?

The unstable loading of a

Cassette tape

Does the “H” signal appear

at Ic501 Pin57 during

inserting the CST ?

Does the “L” signal appear

at Ic501 Pin19 during

inserting the CST?

Check the Deck

Mechanism.

Check the CST SW and

the peripheral circuitry.

Refer to “SMPS DRUM

12 Volt Trouble Shooting”.

Is 5.3V applied to

R544 ?

Refer to SMPS 5.3VA

troubleshooting.

Check IC501

Pins74, 75, 76, 77.

Caution: Auto stop can occur because Grease or Oil is dried up

Check the Drum Motor

signal.

Does 5.2V appear at

RS501?

Check the Q116 Power

Circuit.

Do T/UP Reel Pulses

appear at Q514

Base terminal ?

Replace the T/UP Reel

Sensor (RS501).

VR168 - 923-03485 3-5 D35E COMBO - ELECTRICAL

ELECTRICAL

TROUBLESHOOTING (CONTINUED)

YES

NO

Are the connecting patterns and the Components

between IC501 Pin26 and PMC01 Pin11 short?

NO

YES

N

O

N

O

NO

YES

3. SERVO CIRCUIT

(1) Unstable Video in PB MODE

Unstable Video in

PB Mode.

Does the Noise level of the

screen change periodically?

Do the CTL pulses appear

at IC501 Pin37?

Does the CFG waveform

appear at IC501

Pin40?

On tracking do the CTL

pulses move?

Does the Video Envelope

waveform appear at

IC501 Pin12?

Replace 501.IC

(2) When the Drum Motor

doesn’t run.(2)

When the Drum Motor

doesn’t run,

Does 12V appear at

PMC01 Pin8?

Does 2.8V appear at

PMC01 Pin12?

Check the connector

(PMC01) and the Drum

Motor Ass’y.

Is the adjustment height of

the CTL Head accurate?

Replace 501.IC

Refer to “When the Y signal

doesn’t appear on the

screen in PB Mode”.

Refer to “(2)

No 12VA of Power section”

Do the Drum PWM Pulses

appear at 501

Pin26?

IC

Are the foil patterns and

the Components between

IC501 Pin26 and PMC01

Pin12 short?

Do the DFG Pulses appear

at the IC501 Pin38?

Do the Drum PWM Pulses

appear at 501

Pin26?

IC

Readjust the height of the

CTL Head

Do the DFG Pulses appear

at PMC01 Pin11?

Replace the Cap M.

Aren’t the foil patterns and

the Components between

IC501 Pin 38 and PMC01

Pin11 short?

Replace 501.IC

VR168 - 923-03485 3-6 D35E COMBO - ELECTRICAL

ELECTRICAL

N O

NO

YES

NO

YES

NO

(3) When the Capstan Motor doesn’t run

Does 12VA appear at PMC01?

When the Capstan Motor doesn’t run,

Does 2.8V appear at PMC01?

Check PMC01 and the Capstan

Motor Ass’y.

Does the Capstan PWM signal appear at

IC501 Pin25?

Are the foil patterns and Components

between IC501 Pin25 and PMC01

Pin9 short?

Does the CFG signal come into

IC501 Pin40?

Are the foil patterns and Components

between IC501 Pin 25 and PMC01

Pin9 short?

Does the CFG signal appear at

PMC01 Pin1?

Does the PWM signal appear at

IC501 Pin25?

Replace IC501.

Refer to “SMPS (CAPSTAN/12Volt)

Trouble Shooting”.

Are the foil patterns and component

between IC501 Pin40 and PMC01

Pin1 short?

Check the Capstan Motor Ass’y.

TROUBLESHOOTING (CONTINUED)

VR168 - 923-03485 3-7 D35E COMBO - ELECTRICAL

ELECTRICAL

TROUBLESHOOTING (CONTINUED)

(3)

KEY doesn't work.

YES

NO

N

O

NO

YES

NO

N

O

Replace the defective

switches.

KEY doesn’t work.

Is 5V applied to

IC501 Pin 15?

Does LED or FLD change

when a function button is

pressed?

Refer to “SMPS 5.3VA

Trouble Shooting”.

4. OSD CIRCUIT

1) No OSD display.

2) No F.OSD display.

No OSD display.

Is 5.3V applied to

IC501 Pin 42?

Does oscillation occur at

IC501 Pins 52, 53?

Does oscillation occur at

IC501 Pins 50, 51?

Replace IC501.

No F.OSD display.

Refer to “(1) No OSD

display”.

Does the C.SYNC signal

appear at IC501 Pin87?

Replace IC501.

(3) I2C BUS CHECK

Check or Replace the

Peripheral Circuitry. (L506,

R517, C519, C518, R518)

The I2C waves don’t

come out.

Does Power appear at

the Pull up impedence

(R508, R510)?

Replace IC501.

Refer to “SMPS 5.3VA

Trouble Shooting”.

Is the oscillation input to

Q501 base?

Refer to “AVCP. C. Sync.

Trouble shooting”.

Check or Replace the

Peripheral Circuitry. (L506,

R517, C519, C518, R518)

Check whether X301

oscillates

Refer to “SMPS 5.3VA

Trouble Shooting”.

VR168 - 923-03485 3-8 D35E COMBO - ELECTRICAL

ELECTRICAL

YES

No Video in EE Mode

Does the Video signal

appear at IC301

Pins28, 30, 31?

Is 5.2V applied to IC301

Pins12, 36, 61, 67, 90, 96?

Does the Video signal

appear at IC301 Pin 52?

Does the Video signal

appear at IC501 Pin 45?

Does the Video signal

appear at the Emitter

terminal of Q801?

Check DVD Video Input (IC802, Pin29), Tuner Video Input

(TU701 Pin24), Line Video Input (JK801), respectively.

Check the REG 5V Line.

(Power Circuit)

Is I2C BUS signal applied to

IC301 Pins 62, 63?

Check the path of the signal

between Ic301 Pin

52 and IC501 Pins 43, 45.

Is there 12V on the plus

terminal of C822?

Replace Q801.

Check C330. (AGC)

Replace IC301.

Check the REG 12V Line.

(Power Circuit)

Check the System Circuit.

(Refer to ‘SYSTEM I2C BUS

CHECK Trouble Shooting’)

5. Y/C CIRCUIT

(1) No Video in EE Mode

DVD TROUBLESHOOTING (CONTINUED)

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Zenith XBV243 series User manual

Zenith XBV243 series User manual

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