LG LGXBR-342 Service manual

VCR+DVD RECODER

SERVICE MANUAL

MODEL : LGXBR342

CAUTION

BEFORE SERVICING THE UNIT, READ THE “SAFETY PRECAUTIONS”
IN THIS MANUAL.

MODEL : LGXBR342SERVICE MANUAL

P/NO : 3829RGN002W

Printed in Korea

JANUARY, 2004

CD-R/RW

1-1

SECTION 1

SUMMARY

CONTENTS

PRODUCT SAFETY SERVICING GUIDELINES FOR VIDEO PRODUCTS ............. 1-2

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

SPECIFICATIONS ...................................................................................................................... 1-4

1-2

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 compo­nents, 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.

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 extension cords. Explain that a forest of
extensions, sprouting from a single outlet, can lead to disastrous conse­quences to home and family.

PRODUCT SAFETY SERVICING GUIDELINES FOR VIDEO PRODUCTS

A.C. Voltmeter

Good Earth Ground
such as the Water
Pipe, Conduit, etc.

0.15uF

1500 OHM

10 WATT

Place this probe
on each exposed
metal part.

1-3

SERVICING PRECAUTIONS

CAUTION: Before servicing the VCR + DVD RECODER 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 publications, always follow the safety precau­tions.

Remember Safety First:

General Servicing Precautions

1. Always unplug the VCR + DVD RECODER 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 electrical

plug or other electrical connection.

(3) Connecting a test substitute in parallel with an elec-

trolytic 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 VCR + DVD
RECODER or any of its assemblies.

3. Unless specified otherwise in this service data, clean
electrical contacts by applying an appropriate contact
cleaning solution to the contacts with a pipe cleaner,
cotton-tipped swab, or comparable soft applicator.
Unless specified otherwise in this service data, lubrication
of contacts is not required.

4. Do not defeat any plug/socket B+ voltage interlocks with
whitch instruments covered by this service manual might
be equipped.

5. Do not apply AC power to this VCR + DVD RECODER
and / or any of its electrical assemblies unless all solid­state device heat sinks are correctly installed.

6. Always connect the test instrument ground lead to an
appropriate ground before connecting the test instrument
positive lead. Always remove the test instrument 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 (Note 1) should be more than 1M­ohm.
Note 1: 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 compo­nent or semiconductor-equipped assembly, drain off any
electrostatic charge on your body by touching 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 surface 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
generate an electrical charge sufficient to damage ES
devices.

6. Do not remove a replacement ES device from its protec­tive 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 conductive material).

7. Immediately before removing the protective material from
the leads of a replacement ES device, touch the protective
material to the chassis or circuit assembly 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. (Normally 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.)

1-4

SPECIFICATIONS

General

Power requirements AC 120V, 50/60 Hz
Power consumption 35W
Dimensions (approx.) 430 X 83.5 X 360 mm
Mass (approx.) 6.8 kg
Operating temperature 5 °C ~ 40 °C
Standard Condition -20 °C ~ -60 °C
Signal system NTSC

VDR PART

Read Disc Format DVD Disc : DVD Video Specification Book.

CD-DA Disc : RED Book.
Write Disc Format DVD-R/DVD-R/W Disc : DVD-RW Recorder Specification Book
Video System NTSC
Data Multiplexing MPEG-2(ISO/IEC 13818-1)
Data Decoding Standards MPEG-1, MPEG-2
Audio Compression Read : AC-3 : ATSC Standard for ATV MPEG-1, MPEG-2

Write : MPEG-1, Layer-2

VCR PART

Video Head System Double azimuth 4head helical scanning
Tape Format Tape width 12.7mm(0.5 inch)
Timer 24hours display type

OUTOUT

VIDEO OUTPUTS 1.0 V (p-p), 75 Ω negative sync,RCA jack x 1
S-VIDEO OUTPUT (Y)1.0 V (p-p), 75 Ω negative sync, Mini DIN 4-pin x 1

(C)0.3 V (p-p), 75 Ω
COMPONENT VIDEO OUTPUT (Y)1.0 V (p-p),75 Ω negative sync, RCA jack x 1

(Pb)/(Pr)0.7 V (p-p), 75 Ω
Audio output (analog output) (-)6dBm, less than 1kΩ RCA jack x 2
Audio output (digital output) 0.5 V (p-p), 75 Ω , RCA jack x 1
Audio output (optical output) 5 V (p-p), 75 Ω , Optical connector x 1

2-1

SECTION 2

CABINET & MAIN CHASSIS

CONTENTS

EXPLODED VIEWS .....................................................................................................................2-2

1. Cabinet and Main Frame Section ...........................................................................................2-2

2. Packing Accessory Section....................................................................................................2-3

2-2

EXPLODED VIEWS

1. Cabinet and Main Frame Section

284

261

452

452

320

265

467

468

263

264

250

300

463

463

463

261A

261A

261A

283

280

A43

457

276

260

457

463

457

469

469

A50

A47

A48

A46

A00

457

TU701

323

A52

270

A26

A60

466

463

466

256

463

255

469

257

A47A

A44

452

A

5

4

3

2

1

BCD

2-3

2. Packing Accessory Section

BATTERY

808

BAG

804

PACKING

803

806

INSTRUCTION ASSEMBLY

CABLE(COAXIAL)

810

CABLE ASS'Y RF

801

REMOCON

900

BOX CARTON

802

PACKING

803

811

812

PLUG ASS'Y 1WAY

PLUG ASS'Y 2WAY

OPTIONAL PARTS

3-13-1

SECTION 3

ELECTRICAL

CONTENTS

OVERALL WIRING DIAGRAM..............................3-2

VCR PART
ELECTRICAL ADJUSTMENT

PROCEDURES

............................................................3-3

VCR ELECTRICAL TROUBLESHOOTING
GUIDE

.............................................................................3-4

1. POWER(SMPS) CIRCUIT .......................................3-4

2. SYSTEM/KEY CIRCUIT ..........................................3-7

3. SERVO CIRCUIT ...................................................3--8

4. OSD CIRCUIT .......................................................3-10

5. Y/C CIRCUIT..........................................................3-11

6. TUNER/IF CIRCUIT...............................................3-15

7. Hi-Fi CIRCUIT........................................................3-17

BLOCK DIAGRAMS................................................3-20

1. POWER(SMPS) BLOCK DIAGRAM......................3-20

2. TUNER/MTZ BLOCK DIAGRAM...........................3-22

3. Y/C BLOCK DIAGRAM..........................................3-24

4. NORMAL AUDIO BLOCK DIAGRAM ....................3-26

5. JACK BLOCK DIAGRAM ......................................3-28

6. Hi-Fi BLOCK DIAGRAM ........................................3-30

7. SYSTEM BLOCK DIAGRAM.................................3-32

CIRCUIT DIAGRAMS..............................................3-34

1. POWER(SMPS) CIRCUIT DIAGRAM ...................3-34

2. TU/IF CIRCUIT DIAGRAM ....................................3-36

3. A/V CIRCUIT DIAGRAM........................................3-38

4. JACK CIRCUIT DIAGRAM ....................................3-40

5. Hi-Fi CIRCUIT DIAGRAM......................................3-42

6. SYSTEM CIRCUIT DIAGRAM...............................3-44

7. TIMER CIRCUIT DIAGRAM ..................................3-46

• WAVEFORMS .........................................................3-48

• CIRCUIT VOLTAGE CHART ...................................3-50

PRINTED CIRCUIT DIAGRAMS.........................3-52

1. VCR P.C.BOARD ...................................................3-52

2. POWER P.C.BOARD ............................................3-54

3. TIMER P.C.BOARD ..............................................3-54

4. KEY P.C.BOARD ..................................................3-56

5. JACK P.C.BOARD ................................................3-57

VDR PART
ELECTRICAL TROUBLESHOOTING

GUIDE & WAVEFORMS

........................................3-58

1. POWER(SMPS) CIRCUIT .....................................3-58

BLOCK DIAGRAMS................................................3-65

1. VDR MAIN H/ W BLOCK DIAGRAM.....................3-65

2. POWER BLOCK DIAGRAM ..................................3-66

3. AUDIO IN/ OUT BLOCK DIAGRAM......................3-67

4. CPU & CONTROL REGISTER

BLOCK DIAGRAM.................................................3-68

5. VIDEO IN/ OUT BLOCK DIAGRAM ......................3-69

CIRCUIT DIAGRAMS..............................................3-70

1. E5_BGA, POWER, UART2 CIRCUIT DIAGRAM..3-70

2. DDR_SDRAM, FLASH CIRCUIT DIAGRAM.........3-72

3. RST. CONTROL/STATUS_REG/ATAPI,

HOST_CPLD/LATCH CIRCUIT DIAGRAM ...........3-74

4. 1394, ETHERNET_CONNECTOR

CIRCUIT DIAGRAM ..............................................3-76

5. VIDEO_IN/OUT CIRCUIT DIAGRAM....................3-78

6. AUDIO IN/OUT, NON-STD_VIDEO

CIRCUIT DIAGRAM ..............................................3-80

7. AUDIO DAC, VIDEO_Y/MIXER

CIRCUIT DIAGRAM ..............................................3-82

8. FRONT A/V, 1934 JACK CIRCUIT DIAGRAM ......3-84

• WAVEFORMS .........................................................3-86

• CIRCUIT VOLTAGE CHART ...................................3-90

PRINTED CIRCUIT DIAGRAMS.........................3-94

1. VCR P.C.BOARD(TOP VIEW) ...............................3-94

2. POWER P.C.BOARD (BOTTOM VIEW)................3-96

RL-01A LOADER PART
ELECTRICAL TROUBLESHOOTING

GUIDE

...........................................................................3-98

BLOCK DIAGRAMS & DESCRIPTION ..........3-112

1. OVERALL BLOCK DIAGRAM .............................3-112

2. MAJOR IC INTERNAL BLOCK DIAGRAM AND

PIN DESCRIPTION .............................................3-113

3. MAJOR IC INTERNAL BLOCK DIAGRAM AND

PIN DESCRIPTION .............................................3-118

4. IC302(UPD76F0047):MICOM..............................3-127

WAVEFORMS ..........................................................3-131

1. POWER & RESET SIGNAL ................................3-131

2. MAIN CLOCK1 FOR IC202 (16.9MHZ)...............3-131

3. MAIN CLOCK2 FOR IC302 (20MHZ)..................3-132

4. SDRAM CLOCK ..................................................3-132

5. TRAY OPEN/CLOSE SIGNAL 1 ..........................3-133

6. TRAY OPEN/CLOSE SIGNAL 2 ..........................3-133

7. SLED MOVE SIGNAL 1.......................................3-134

8. SLED MOVE SIGNAL 2.......................................3-134

9. FOCUS SEARCH SIGNAL..................................3-135

10. LASER TURN ON SIGNAL ...............................3-135

11. DISC TYPE JUDGEMENT WAVEFORM

(CD SERIES) .....................................................3-136

12. DISC TYPE JUDGEMENT WAVEFORM

(CD&CD-R)........................................................3-136

13. DISC TYPE JUDGEMENT WAVEFORM

(CD-RW) ............................................................3-137

14. DISC TYPE JUDGEMENT WAVEFORM

(DVD SERIES)...................................................3-137

15. DISC TYPE JUDGEMENT WAVEFORM

(DVD_SINGLE&R).............................................3-138

16. DISC TYPE JUDGEMENT WAVEFORM

(DVD _DUAL) ....................................................3-138

17. DISC TYPE JUDGEMENT WAVEFORM

(DVDRW)...........................................................3-139

18. SPINDLE WAVEFORM1....................................3-139

19. SPINDLE WAVEFORM2....................................3-140

20. FOCUS ON SIGNAL(CD)..................................3-140

21. FOCUS ON SIGNAL(CD)..................................3-141

22. FOCUS ON SIGNAL(DVD)................................3-141

23. FOCUS ON SIGNAL (DVD)...............................3-142

24. TRACK OFF SIGNAL(CD).................................3-142

25. TRACK OFF SIGNAL(DVD) ..............................3-143

26. TILT DRIVER SIGNAL(DISC READING) ..........3-143

27. RF WAVEFORM(DVD) ......................................3-144

28. RF WAVEFORM(CD).........................................3-144

29. WOBBLE(DVD-R/RW)_READING ....................3-145

30. WOBBLE(DVD+R/RW)_READING&WRITING

=>X1 SPEED....................................................3-145

31. LD ENABLE(DVD) .............................................3-146

32. LD ENABLE(CD) ...............................................3-146

33. LASER POWER(READING)_DVD+RW............3-147

34. LASER POWER(ERASE)_DVD+RW ................3-147

35. LASER POWER(WRITING)_INITIAL STATE ....3-148

36. LASER POWER(WRITING)_PROCESSING ....3-148

CIRCUIT DIAGRAMS............................................3-149

1. RF CIRCUIT DIAGRAM .....................................3-149

2. DSP CIRCUIT DIAGRAM....................................3-151

3. µ-COM CIRCUIT DIAGRAM................................3-153

PRINTED CIRCUIT DIAGRAMS.......................3-155

1. MAIN P.C.BOARD(TOP SIDE) ............................3-155

OVERALL WIRING DIAGRAM

3-2

3-3

ELECTRICAL ADJUSTMENT PROCEDURES

1. Servo Adjustment

1) PG Adjustment

• Adjustment And Specification

• Test Equipment
a) OSCILLOSCOPE
b) NTSC MODEL : NTSC SP TEST TAPE

MODE

PLAY

• Adjustment Procedure

a) Insert the SP Test Tape and play.
b) Connect the CH1 of the oscilloscope to the H/SW and CH2 to the “VCR VIDEO” TP for the VCR.
c) Trigger the mixed Combo Video Signal of CH2 to the CH1 H/SW, and then check the distance (time dif-

ference), which is from the selected A(B) Head point of the H/SW(W5D1, W5D2) signal to the starting
point of the vertical synchronized signal, to 6.5H ± 0.5H (412µs, 1H=63.5µs).

• PG Adjustment Method

a-1) Playback the SP standard tape
b-2) Press the “ENTER” key on the Remote controller and the “REC” key on the Front Panel at the same

time, then it goes into Tracking initial mode. < Digitron[ - - ] >
c-3) Repeat the above step(No.b-2), then it finishes the PG adjusting automatically. < Digitron[ PG ] >
d-4) Stop the playback, then it goes out of PG adjusting mode after mony the PG data.

• CONNECTION

• WAVEFORM

V.Out

H/SW(W5D1, W5D2)

R/C TRK JIG KEY 6.5 ± 0.5H

MEASUREMENT POINT ADJUSTMENT POINT SPECIFICATION

H/SW

(W5D1, W5D2)

TP

(VCR

VIDEO)

(CH2)

(CH1)

OSCILLOSCOPE

CH1 CH2

R/C KEY

H/SW

(W5D1, W5D2)

VCR BOARDVDR BOARD

"VCR VIDEO" TP

VCR PART

H/SW

Composite

VIDEO

6.5H(412Ωs)

3-4

VCR ELECTRICAL TROUBLESHOOTING GUIDE

1. Power(SMPS) CIRCUIT

NO 5.3VA.

Replace the F101
(Use the same Fuse)

Is the F101 normal?

Is the TH01
Normal?

Is the BD101
Normal?

NO

NO

NO

NO

NO

NO

NO

NO

NO

NO

NO

Replace the BD101

Replace the TH01

Is the D102
normal?

Check or Replace
the D102

Replace the D121

Replace the IC103

Replace the D126

Replace the D129

Replace the D130

Replace the D127

Replace the D128

YES

YES

YES

YES

YES

YES

YES

YES

YES

YES

Is the Vcc (11V - 18V)
supplied to IC101 Pin2?

NO

Is the D121
normal?

Is there about 2.5V
at the IC103 Pin1?

Is the D126
normal?

Is the D129
normal?

Is the D130
normal?

Is the D127
normal?

Is the D128
normal?

YES

Power Line of Main
PCB(VCR) is short

VCR ELECTRICAL TROUBLESHOOTING GUIDE

3-5

No 12VA

Check or Replace
the D126

Is the Vcc(13V)
supplied to C130?

Check or Replace
the Cap / Drum

Is the D132
Normal?

NO

NO

Replace the D132

YES

YES

(To Cap, Drum Motor )

No REG 12V

Check or Replace
the D126

Check the ‘PWR CTL
“H”’signal from µ-com

Check the 33V Line

Replace the Q126

Is the Vcc(13V) sup­plied to Q126Collector?

Is the Vcc(33V) sup­plied to Q126 Base?

Is the Q126 Nomal?

Check or Replace
the D126

NO

NO

NO

YES

YES

YES

NO VFD

Check or Replace
the R107

Is the R107
Normal?

Is the D128
Normal?

NO

Check or Replace
the D128

Check or Replace
the ZD151

NO

NO

YES

Is the ZD151
Normal?

Check or Replace
the D127

YES

YES

No 33V

Check or Replace
the D130

Is the Vcc(33V) sup­plied to Q123 Emittor?

Is the Q123 Base
‘H’?

NO

Check the ‘PWR CTL
“H”’signal from µ-com

NO

YES

Check or Replace
the Q123

YES

3-6

VCR ELECTRICAL TROUBLESHOOTING GUIDE

No 28V (HSR)

Check or Replace
the D129

Is the Vcc(30V) supplied
to Q120 Collector?

Is the Vcc(33V) supplied
to Q121 Collector?

Is the Vcc(30V) sup­plied to Q120 Base?

NO

NO

Check or Replace
the ZD153

NO

Check the ‘HSR “H”
signal from µ-com

Check or Replace the
Q121/Q122 & 33V line

YES

YES

Check or Replace
the Q120

YES

3-7

2. SYSTEM/KEY CIRCUIT

(1) AUTO STOP

(2) The unstable loading of a Cassette tape

Auto Stop

Does the SW30 waveform
appear at IC501 Pin18?

Do the T-UP Reel Pulses
appear at IC501 Pin80?

Is 12V applied to PMC01
Pin8?

Check the Drum Motor
signal.

Does 5V appear at the
RS501?

Check the Q124 Power
Circuit.

Refer to “SMPS DRUM
12 Volt Trouble Shooting”.

Is 5V applied to R531 ?

Refer to SMPS 5.3VA
troubleshooting.

Check IC501
Pins22, 23, 24, 25.

Do T/UP Reel Pulses
appear at the point
between R556 and R536?

Replace the T/UP Reel
Sensor (RS501).

Check the CST SW and
the peripheral circuitry.

Replace the IC501.

The unstable loading of a
Cassette tape

Does the “H” signal appear
at IC501 Pin60 while
inserting the CST ?

Does the “L” signal appear
at IC501 Pin19 while
inserting the CST?

Check the Deck
Mechanism.

Note :

Auto stop can occur because Grease or Oil has dried up

YES

YES

NO

YES

YES

YES

NO

NO

NO

NO

NO

NO NO

YES

YES YES

VCR ELECTRICAL TROUBLESHOOTING GUIDE

3-8

3. SERVO CIRCUIT

(1) Unstable Video in PB MODE

Does the Noise level of the
screen change
periodically?

Do the CTL pulses appear
at IC501 Pin97?

Is the height adjustment of

the CTL Head accurate?

Check Deck Motor.

Readjust the height of the
CTL Head.

Replace IC501.

Refer to “When the Y signal
doesn’t appear on the
screen in PB Mode”.

Confirm the CFG
waveform at IC501 Pin87?

On tracking, do the CTL
pulses move?

Does the Video Envelope
waveform appear at IC501
Pin9?

Replace IC501.

YES

YES

YES

NO NO

NO

NO

NO

(2) When the Drum Motor

(2) doesn’t run.

Do the DFG Pulses appear
at PMC01 Pin11?

Replace the Cap M.

Are the foil patterns and
the Components between
IC501 Pin 90 and PMC01
Pin11 shorted?

Replace IC501.

Refer to “(2)
No 12VA of Power section”

Do the Drum PWM Pulses
appear at IC501 Pin76?

Are the foil patterns and

the Components between
IC501 Pin76 and PMC01
Pin12 shorted?

Do the DFG Pulses appear

at IC501 Pin90?

Do the Drum PWM Pulses
appear at IC501 Pin76?

Are the connecting patterns and the Components

between IC501 Pin76 and PMC01 Pin12 shorted?

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.

NO

YES

YES

YES

NO

NO

NO

NO

NO

YES

YES

YES

VCR ELECTRICAL TROUBLESHOOTING GUIDE

3-9

Does the CFG signal appear at
PMC01 Pin1?

Does the PWM signal appear at IC501
Pin77?

Does 2.8V appear at PMC01?

Check the PMC01 and the Capstan
Motor Ass’y.

Does the Capstan PWM signal appear at
IC501 Pin77?

Are the foil patterns and Components
between IC501 Pin77 and PMC01
Pin9 shorted?

Does the CFG signal come into IC501
Pin87?

Are the foil patterns and Components
between IC501 Pin77 and PMC01
Pin9 shorted?

2. SERVO CIRCUIT

(3) When the Capstan Motor doesn’t run,

NO

NO

NO

YES

YES

YES

When the Capstan Motor doesn’t run,

Does 12VA appear at PMC01?

YES

Replace IC501.

YES

NO

NO

YES

Refer to “SMPS(CAPSTAN/12Volt)
Trouble Shooting”.

Are the foil patterns and component
between IC501 Pin87 and PMC01
Pin1 shorted?

Check the Capstan Motor Ass’y.

NO

VCR ELECTRICAL TROUBLESHOOTING GUIDE

3-10

4. OSD CIRCUIT

(1) I

2

C BUS CHECK

Keys do not work

Is 5V applied to IC501
Pin78?

Does FLD change when
a function button is
pressed?

No I2C bus communication

Does Power appear at the
Pull up impedence
(R569, R507)?

Replace IC501.

Refer to “SMPS 5.3VA
Trouble Shooting”.

Replace the defective
switches.

Refer to “SMPS 5.3VA
Trouble Shooting”.

YES

YES

NO

NO

NO

2. SERVO CIRCUIT

(4) Keys do not work

VCR ELECTRICAL TROUBLESHOOTING GUIDE

3-11

5. Y/C CIRCUIT

(1) No Video in EE Mode,

No Video in EE Mode

Does the Video signal
appear at IC301
Pins28, 30, 32?

Is REG 5.0V applied to
IC301Pins23, 44, 45, 52, 68,
77?

Does the Video signal
appear at IC301 Pin26?

Does the Video signal
appear at IC501 Pin52?

Does the Video signal
appear at PMD02 Pin7?

Does the Video signal
appear at the PMD02
Pin5?

Does the Video signal
appear at the JK602
Video Out Jack?

Check the REG 5V Line.
(Power Circuit)

Is I2C BUS signal applied to
IC301 Pins53, 54, 55?

Replace IC301.

Check the path of the sig­nal between IC301 Pin 26
and IC501 Pins50, 52.

Is there REG12 on the
plus terminal of C653?

Check the REG 12V Line.
(Power Circuit)

Check the Q605
(Video Buffer)

Check the VDR
Module

Check the IC601 and
Video Out Line

Check the System Circuit.
(Refer to ‘SYSTEM I2C BUS
CHECK Trouble Shooting’)

YES

YES

YES

YES

YES

YES

YES

YES

NO

NO

NO

NO

NO

NO

NO

NO

Check the REG 5V Line.
(Power Circuit)

NO

NO

Check VDR Video Input
(PMD02 Pin 5), Tuner Video
Input (TU701 Pin24), Line
Video Input (IC602 Pins 1, 3,
5, 7), respectively.

VCR ELECTRICAL TROUBLESHOOTING GUIDE

3-12

3. Y/C CIRCUIT

(2) When the Y(Luminance) signal doesn’t appear on the screen in PB Mode,

Is 5V applied to IC301
Pins23, 44, 45, 52, 68, 77?

Is the Y/C Bus siganl
applied to IC301 Pins53,
54, 55?

Does the normal RF signal
appear at IC301 Pin14?

Check the line of the REG
5V Line. (Power Circuit)

Check the System Circuit.
(IC501 Pin18)

Check the V.H.S/W level.

Refer to ‘SYSTEM Y/C
BUS CHECK Trouble
Shooting’.

Is the V.H.S/W signal
applied to IC301 Pin57?

Does the Rectangular
waveform(5V) appear at
IC301 Pin57(V.H.S/W)

Clean the Drum.

Check C324.

Check R328, C322, C323.

Does the Y(Luminance)
signal appear at IC301
Pin20?

Is the Y(Luminance) Video
waveform showed up at
IC301 Pin22?

Replace IC301.

NO

YES

YES

YES

YES

YES

YES

YES

NO

NO

NO

NO

NO

NO

VCR ELECTRICAL TROUBLESHOOTING GUIDE

3-13

3. Y/C CIRCUIT

(3) When the C(Color) signal doesn’t appear on the screen in PB Mode,

Is 5V applied to IC301
Pins23, 44, 45, 52, 68, 77?

Does the Color signal
appear at IC301
Pins41, 50?

Check the line of the REG
5V Line. (Power Circuit)

Replace X301.

Check C342, C341,
R333.

Is X301 (3.58MHz)
normal?

Replace IC301.

Does the Color signal
appear at IC301 Pin48?

Replace IC301.

NO

YES

YES

YES

NO

NO

NO

VCR ELECTRICAL TROUBLESHOOTING GUIDE

3-14

3. Y/C CIRCUIT

(4) When the Video signal doesn’t appear on the screen in REC Mode,

YES

YES

NO

NO

YES

YES

YES

YES

YES

Check system part
(V.H/SW)

Replace the IC301.

Check the drum

*OPTION
Pins72, 73, 74(SP)
Pins65, 66, 67(EP)

REC mode

Check the EE mode

NO

Is EE mode normal?

Is color

normal?

A

A

YES YES

Is brightness normal?

Does signal appear at
IC301 Pins41, 50?

NO

Check X301 oscillation
frequency.

YES

Is the brightness signal sup­plied to IC301 Pins18?

Is 5V supplied to IC301
Pins23, 44, 45, 68, 77?

Check the power of Pins23,
44, 45, 52, 68, 77.

Check the 5V power

NO

NO

NO

NO

NO

Is Y/C Bus applied to
IC301 Pins53, 54, 55?

Check the REG 5V power

Check system part

Do X301 and X-TAL
oscillate?

Check X301

Is V.H SW supplied to
IC301 Pin57?

Does the FM signal appear
at IC301*?

VCR ELECTRICAL TROUBLESHOOTING GUIDE

3-15

6. Tuner/IF CIRCUIT

(1) No Picture on the TV screen

No picture on the TV
screen

Does the Video signal
appear at TU701 Pin16.

YES YES

Is +33V applied to TU701
Pin14?

YES

Is +5V applied to TU701
Pin3?

NO

Does the video signal
appear at IC302 Pin7.

NO

Does the Video signal
appear at IC501 Pin 52.

YES

NO

Does the Video signal
appear at IC602 Pin 7.

YES

NO

Check the signal flow from IC602
Pin7 to JK601 Pin Video out.

YES

Check 33V line.

NO

Check 5V line.

NO

YES

Does the Clock signal
appear at TU701 Pin9?

Check the l2C Clock Signal
of µ-COM Pin71.

NO

YES

Does the data signal
appear at TU701 Pin10?

Replace Tuner.

Check the signal flow from
IC501 Pin27.(Pin27 is ‘L’
state in Tuner Mode)

Check the signal from IC301
Pin26 to IC501 Pin50.

Check the signal from IC501 Pin52 to IC602 Pin1 and IC602 Pin2.
(IC602 Pin2 is ‘L’ state in VHS mode)

Check the l2C Data Signal
of µ-COM Pin72.

NO

VCR ELECTRICAL TROUBLESHOOTING GUIDE

3-16

VCR ELECTRICAL TROUBLESHOOTING GUIDE

(B) No Sound

No Sound.

Check the Vcc of IC701 Pins1, 11, 19,
22, 33.

YES

Check 5.2V Line.

NO

Check the Tuner SiF signal at IC701
Pin2.

YES

Check the oscillator of IC701 Pins5, 6.

YES

Check the Audio of IC701 Pins30, 31.

YES

Check the Audio of IC801 Pins2, 3.

YES

Check the Audio of IC801 Pins16, 17.

YES

Check the Tuner SIF of TU701 Pin22.

NO

Replace X751

NO

Check the IIC Clock and Data at IC701
Pins12, 13.

NO

Check the signal flow from IC701
Pins30, 31 to IC801 Pins2, 3.

NO

Check the IIC Clock and Data at IC801
Pins42, 43.

NO

3-17

VCR ELECTRICAL TROUBLESHOOTING GUIDE

7. Hi-Fi CIRCUIT

(1) No Sound(EE Mode)

YES

No Sound.

Check the TU Audio of IC801
Pins2, 3.

Check the DVD Audio of IC801
Pins4, 5.

Check the AV1 Audio of IC801
Pins6, 7.

Check the AV2 Audio of IC801
Pins8, 9.

Check the Vcc of IC801 Pins34, 40,
IC802 Pin4.

YES

Check the IIC Clock and DATA at
IC801 Pins42, 43

YES

Check the Audio of IC801 Pins16, 17.

YES

Check the JK601.

Check the IC701 Pins30, 31.

NO

Check the VDR MODULE.
(PMD02 Pins23, 25).

NO

NO

Check the RCA Jack.
(JK601 Scart1 Audio in L, R).

NO

Check the VDR MODULE.
(PMD02 Pins27, 29).

Check the Power 5.2V, 12V.

YES

NO

Check the IC501 Pins71, 72.

NO

Replace IC801.

NO

3-18

VCR ELECTRICAL TROUBLESHOOTING GUIDE

3. Y/C CIRCUIT

(2) Hi-Fi Playback

YES

YES

YES

YES

PB mode

No Sound.

Check the Vcc of IC801
(Pins34, 40)

Check the Hi-Fi Selection switch.
(IC801 Pin41) and the Tape quality.

Is the RF Envelope at
IC801 Pin44 over 2Vp-p?

YES

Check IC801 Pin42(Data),
Pin43(Clock)

YES

Do Audio Signals appear at
IC801 Pin16(L-CH), 17(R-CH)?

YES

Do Audio Signals appear at
JK601?

Check Power 5.2V, 12V.

NO

Check IC501 Pin19
(A.H/SW)

NO

NO

Check the parts of µ-COM
(IC501 Pins71, 72)

NO

Check the Connection at
P3D01 Pins7, 9.

NO

Check the Jack(JK601)

NO

3-19

(3)

Hi-Fi REC.

It can’t be recorded Hi-Fi Audio
signal.

Check Vcc of IC801.(Pins34, 40)

YES

YES

Check IC801 Pin42(Data), Pin43(CLOCK).

YES

Do Audio signals appear at IC801
Pins16, 17?

YES

Do FM Audio signals appear at IC801
Pin36?

YES

Check the Contact Point of Drum
Connector if good then Replace the Drum.

YES

Check Power 5V, 12V.

NO

Check ports of µ-COM.
(IC501 pins 71, 72)

Check Audio input signal of IC801
Pins2, 3(TU.A.), 4, 5(AV1), 6, 7(VDR.A.),
10, 11(AV2).

NO

Replace IC801.

NO

NO

VCR ELECTRICAL TROUBLESHOOTING GUIDE

FUSE
(F101)

NOISE FILTER

BLOCK
(C101,L102,
L101, C102)

SNUBBER

BLOCK

(D103,C115,C116

,R112,R115)

DRIVE & S/W BLOCK

(IC104, D104, R113,

C117,C114)

BD101

TH01

Y-CAP
C110

Y-CAP
C111

+

BR BL

(BK)(WH)

2.5V

3.3V

TO VDR

(P102)

C103

12V

5.0V

TO LOADER

(P103)

FD( +)

FD(-)

-28VA

TO VCR

(P101)

!

!

!

!

5.3VA

5.0V

Cap Vcc

12VA( DRUM)

33V

REG 12V

PWR CTL 'H'

HSR 'H'

DVD PWR CTL

5.0V

SNUBBER

BLOCK
(D101,C105
C106,R103)

DRIVE & S/W BLOCK

(IC101, D102, R105,

C108,C112)

T101

T102

!

!

PHOTO COUPLER

(IC102)

ERROR AMP

(IC103)

FEED-BACK

BLOCK
R121,R122,
C121,R123.

R124.R125

R126)

!

RECTIFIER &

SMOOTING BLOCK

(D128,C133,R130)

RECTIFIER &

SMOOTING BLOCK

(D127,C131,L125,C132)

RECTIFIER &

SMOOTING BLOCK

(D125,C139,L127,C140)

RECTIFIER &

SMOOTING BLOCK

(D124,C129)

RECTIFIER &

SMOOTING BLOCK

(D123,C126,L124,C127)

RECTIFIER &

SMOOTING BLOCK

(D122,C123,L123,C125)

PHOTO COUPLER

(IC105)

ERROR AMP

(IC106)

FEED-BACK

BLOCK
R131,R132,
C141,R133.

R161.R162

R163)

!

12V REG & S/W Block

(IC157,R156,C155)

-12V

12V

1.8V

8.7V

TO FAN

(P103)

RECTIFIER &

SMOOTING BLOCK

(D129,C128,R147)

RECTIFIER &

SMOOTING BLOCK

(D130,C137,R146)

5.0V REG & S/W Block
(IC151,R151,C151)

1.8V REG & S/W Block
(IC160,R159,C152)

3.3V REG & S/W Block
(IC154,R154,C154)

RECTIFIER &

SMOOTING BLOCK

(D126,C136,L122,C130)

RECTIFIER &

SMOOTING BLOCK

(D121,C122,L121,C124)

HSR S/W Block

(Q120,ZD153,C135,

R144,R145,D155,C157)

12V REG & S/W Block

(Q126,R150,ZD152,

C156,C153)

5.0V S/W Block

(Q124,R140,R135,R136

D134,C134)

33V S/W Block

(Q123,R143,R134)

HSR CTL Block

(Q121,Q122,R141)

PWR CTL Block

(Q125,R137,R138)

5 6 7 8

5

1

2

3

6 7 8

2

3

3-20 3-21

BLOCK DIAGRAMS

1. POWER(SMPS) BLOCK DIAGRAM

TU701

TUNER

FROM/TO

MICOM
(IC501)

1. TO JACK PART
(IC603, NJM2750)

2. TO Hi-Fi IC
(IC801)

FROM/TO

MICOM

(IC501)

SIF

33V
(PMP01-6)

5.0V
(PMP01-2)

CH S/W
IIC CLK
IIC DATA
VCR'H'

TO
AVCP IC
(IC301)

FROM
JACK
PART

TU.V.OUT

V.IN

A.IN

Q702

Q703

VDR A.L

VDR A.R

AFT

IC701

MSP3407

IIC CLK

IIC DATA

TU.A.L

TU.A.R

3-22 3-23

2. TUNER/MTZ BLOCK DIAGRAM

3-24 3-25

3. Y/C BLOCK DIAGRAM

EP PB 'A'

EP PB 'B'

SP PB 'B'

SP PB 'A'

64

59 58 57 55 54 53

65

67

72

74

ACC

DET

ENV

DET

C-ROT
RF-SW
IN

Y/C ENA

Y/C DATA

Y/C CLOCK

V.OUT

AUDIO

MUTE

HA SW

P

P

P

C-LPF

MAIN

CONV

3.58M
BPF2

ACC
AMP

ACC
DET

CLAMP

Y

LPF

CLAMP

CLAMP

IN

OUT

VCA

CCD

3.58M
BPF1

Y/C

MIX

6dB

DOUBLE

LIMFMDEM

SUB
LPF

MAIN

DE-EM

PB

FM-EQ

FM

AGC

CNC

YNR

COMB

4.21M
BPF

SUB

CONV

39

37

36

34

26

22

21

P

B

(PB Mode)

EP REC

SP REC

57

V. H/SW55Y/C ENA

54

Y/C DATA

53 51 50 49 48 47

39

38

37

36

34

32

30

28

22

21

20

73

70

69

66

Y/C CLOCK

X-TAL

3.58MHZ

C-LPF

MAIN

CONV

4.21M
BPF

SUB

CONV

DETAIL

ENH

MAIN

EMPHA

REC

FM-EQ

4.7K

FM

MOD

Y

LPF

YNR

COMB

3.58M
BPF1

LINE2

26

V.OUT

DVD

TU/LINE1

VIDEO

AGC

CLAMP

CLAMP

CLAMP

IN

CCD

OUT

VCA

SW

BLOCK

IC302

NL

EMPHA

B-UP
AMP

ACC
AMP

ACC
DET

BGA

REC
APC

REC
APC

320FH

VCO

SLDVX01

SERIAL

DECODER

R

R

B

(REC Mode)