Nad L-55-2 Schematic

SERVICE MANUAL

DVD/VIDEO CD/CD

PLAYER

L55

NAD ELECTRONICS INTERNATIONAL

LONDON

© NAD 2001

SERVICE MANUAL

L55

DVD/VIDEO CD/CD

PLAYER

DVD/VIDEO CD/CD

PLAYER

1-2

1-3

PRODUCT SAFETY SERVICING GUIDELINES FOR VIDEO PRODUCTS

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 YOUR BEING LIABLE FOR ANY RESULTING
PROPERTY DAMAGE OR USER INJURY.

SERVICE WORK SHOULD BE PERFORMED ONLY AFTER YOU
ARE THOROUGHLY FAMILIAR WITH ALL OF THE FOLLOWING
SAFETY CHECKS AND SERVICING GUIDELINES. TO DO
OTHERWISE, INCREASES THE RISK OF POTENTIAL HAZARDS
AND INJURY TO THE USER.

WHILE SERVICING, USE AN ISOLATION TRANSFORMER FOR
PROTECTION FROM A.C. LINE SHOCK.

SAFETY CHECKS

AFTER THE ORIGINAL SERVICE PROBLEM HAS BEEN
CORRECTED. A CHECK SHOULD BE MADE OF THE
FOLLOWING.

SUBJECT : FIRE & SHOCK HAZARD

1. BE SURE THAT ALL COMPONENTS ARE POSITIONED IN
SUCH A WAY AS TO AVOID POSSIBILITY OF ADJACENT
COMPONENT SHORTS. THIS IS ESPECIALLY IMPORTANT
ON THOSE MODULES WHICH ARE TRANSPORTED TO AND
FROM THE REPAIR SHOP.

2. NEVER RELEASE A REPAIR UNLESS ALL PROTECTIVE
DEVICES SUCH AS INSULATORS, BARRIERS, COVERS,
SHIELDS, STRAIN RELIEFS, POWER SUPPLY CORDS, AND
OTHER HARDWARE HAVE BEEN REINSTALLED PER
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, DAMAGED INSULATION (INCLUDING A.C.
CORD). AND REPLACE IF NECESSARY FOLLOW ORIGINAL
LAYOUT, LEAD LENGTH AND DRESS.

5. NO LEAD OR COMPONENT SHOULD TOUCH A RECEIVING
TUBE OR A RESISTOR RATED AT 1 WATT OR MORE. LEAD
TENSION AROUND PROTRUDING METAL SURFACES MUST
BE AVOIDED.

6. ALL CRITICAL COMPONENTS SUCH AS FUSES,
FLAMEPROOF RESISTORS, CAPACITORS, ETC. MUST BE
REPLACED WITH EXACT FACTORY TYPES, DO NOT USE
REPLACEMENT COMPONENTS OTHER THAN THOSE
SPECIFIED OR MAKE UNRECOMMENDED CIRCUIT
MODIFICATIONS.

7. AFTER RE-ASSEMBLY OF THE SET ALWAYS PERFORM AN
A.C.LEAKAGE TEST ON ALL EXPOSED METALLIC PARTS OF
THE CABINET, (THE CHANNEL SELECTOR KNOB, ANTENNA
TERMINALS. HANDLE AND SCREWS) TO BE SURE THE SET
IS SAFETY TO OPERATE WITHOUT DANGER OF
ELECTRICAL SHOCK. DO NOT USE A LINE ISOLATION
TRANSFORMER DURING THIS TEST USE AN A.C.
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,

150.V A.C TYPE CAPACITOR BETWEEN A KNOWN GOOD
EARTH GROUND (WATER PIPE, CONDUIT, ETC.) AND THE
EXPOSED METALLIC PARTS, ONE AT A TIME.
MEASURE THE A.C. VOLTAGE ACROSS THE COMBINATION
OF 1500 OHM RESISTOR AND .15 MFD CAPACITOR.
REVERSE THE A.C. PLUG AND REPEAT A.C. VOLTAGE
MEASUREMENTS FOR EACH EXPOSED METALLIC PART.

VOLTAGE MEASURE MUST NOT EXCEED 75 VOLTS R.M.S.
THIS CORRESPONDS TO 0.5 MILLIAMP A.C ANY VALUE
EXCEEDING THIS LIMIT CONSTITUTES A POTENTIAL
SHOCK HAZARD AND MUST BE CORRECTED IMMEDIATELY.

SUBJECT : GRAPHIC SYMBOLS

SUBJECT : TIPS ON PROPER INSTALLA TION

1. NEVER INSTALL ANY PRODUCT IN A CLOSED-IN RECESS,
CUBBYHOLE OR CLOSELY FITTING SHELF SPACE. OVER
OR CLOSE TO 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
REAR VENTING. THE CUSTOMER SHOULD ALSO AVOID THE
USE OF DECORATIVE SCARVES OR OTHER COVERINGS
WHICH MIGHT OBSTRUCT VENTILATION.

4. WALL AND SHELF MOUNTED INSTALLATIONS USING A
COMMERCAL 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 TEST ON CUSTOMIZED INSTALLATIONS.

5. CAUTION CUSTOMERS AGAINST THE MOUNTING OF A
PRODUCT ON SLOPING SHELF OR A TILTED POSITION,
UNLESS THE PRODUCT IS PROPERLY SECURED.

6. A PRODUCT ON A ROLL-ABOUT CART SHOULD BE STABLE
ON 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 THE USE OF A CART OR
STAND WHICH HAS NOT BEEN LISTED BY UNDERWRITERS
LABORATORIES, INC. FOR USE WITH THEIR SPECIFIC
MODEL OF TELEVISION RECEIVER OR GENERICALLY
APPROVED FOR USE WITH T.V.’S OF THE SAME OR
LARGER SCREEN SIZE.

8. CAUTION CUSTOMERS AGAINST THE USE OF EXTENSION
CORDS, EXPLAIN THAT A FOREST OF EXTENSIONS
SPROUTING FROM A SINGLE OUTLET CAN LEAD TO
DISASTROUS CONSEQUENCES TO HOME AND FAMILY.

THE LIGHTNING FLASH WITH ARROWHEAD SYMBOL, WITHIN AN
EQUILATERAL TRIANGLE, IS INTENDED TO ALERT THE USER TO THE
PRESENCE OF UNINSULATED “DANGEROUS VOLTAGE” WITHIN THE
PRODUCT’S ENCLOSURE THAT MAY BE OF SUFFICIENT MAGNITUDE TO
CONSTITUTE A RISK OF ELECTRIC SHOCK.

THE EXCLAMATION POINT WITHIN AN EQUILATERAL TRIANGLE IS
INTENDED TO ALERT THE USER TO THE PRESENCE OF IMPORTANT
OPERATING AND MAINTENANCE (SERVICING) INSTRUCTIONS IN THE
LITERATURE ACCOMPANYING THE APPLIANCE.

A.C. V OLTMETER

PLACE THIS PROBE
ON EACH EXPOSED
METAL PART

GOOD EARTH GROUND
SUCH AS THE WATER
PIPE. CONDUIT. ETC

10 WATT

1500 OHM

0.15uF

1-4

SERVICING PRECAUTIONS

CAUTION : Before servicing the DVD player 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.

Remember Safety First:

General Servicing Precautions

1. Always unplug the DVD player's 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 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 DVD player 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, cottontipped 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 which
instruments covered by this service manual might be equipped.

5. Do not apply AC power to this DVD player and/or any of its
electrical assemblies unless all solid-state device heat sinks are
correctly installed.

6. Always connect test instrument ground lead to the 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 1M-ohm.
Note 1 : Accessible Conductive Parts including 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 antistatic solder removal device. Some solder
removal devices not classified a “anti-static” can generate
electrical charges sufficient to damage ES devices.

5. Do not use freonpropelled chemicals. These can generate
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. lmmediately 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 handing 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.)

1-5

DVD player/Outputs/Supplied Accessories

[DVD player]

[Outputs]

[Supplied

Accessories]

Power supply AC 230V / 50 Hz (EUROPE), AC 110V/60Hz (USA / CANADA)
Power consumption 15 W
Mass 3.3 kg
External dimensions (W X H X D) 285 x 103x 291 mm
Signal system PAL (EUR) , NTSC (USA / CANADA)
Laser Semiconductor laser, wavelength 650 nm
Frequency range (audio) 4 Hz to 20 kHz
Signal-to-noise ratio (audio) More than 100 dB (EIAJ)
Dynamic range (audio) More than 95 dB (EIAJ)
Harmonic distortion (audio) 0.008 %
Wow and flutter

Below measurable level (less than + 0.001 % (W.PEAK)) (EIAJ)
Operating conditions Temperature: 41°F to 95°F, Operation status: Horizontal
Video output 1.0 V (p-p), 75 , negative sync., RCA jack x 1
S-video output (Y) 1.0 V (p-p), 75 , negative sync., Mini DIN 4-pin x 1

(C) 0.286 V (p-p), 75 ,
SCART video output CVBS 1.0 V (p-p), 75 , negative sync., RCA jack x 1

(RGB) 0.63 V (p-p), 75
Audio output (digital audio) 0.5 V (p-p), 75 , RCA jack x 1
Audio output (optical audio) Optical connector x 1
Audio output (analog audio) 2.0 Vrms(1 KHz, 0 dB), 330 , RCA jack (L, R) x 1

Video cable. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Audio cable. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

* Designs and specifications are subject to change without notice.

1-6

Front Panel

Display Window

POWER indicator

(Standby mode: Blue color)

POWER button

REMOTE SENSOR

DISPLAY WINDOW

OPEN/CLOSE button

SKIP/SCAN buttons

Disc tray

PLAY button

PAUSE/STEP button

STOP button

OPERATING STATUS indicator

CD indicator

VCD indicator

DVD indicator

PROGRAM indicator

Repeat playback
mode indicators

CHP/TRK NUMBER indicator

TOTAL PLAYING
TIME/ELAPSED TIME
indicator

TITLE NUMBER indicator

ANGLE ICON indicator

1-7

Rear Panel

COMPOSITE VIDEO OUT jack

COMPOSITE VIDEO OUT jack

COMPONENT VIDEO OUT jack

MIXED AUDIO OUT jacks

MIXED AUDIO OUT jacks

EURO AV-TV-VCR OUT jack

OPTICAL DIGITAL AUDIO OUT jack

DIGITAL AUDIO OUT jacks
(COAXIAL)

DIGITAL AUDIO OUT jacks
(COAXIAL)

POWER CORD

Connect to an AC 230V, 50Hz
outlet only.

POWER CORD

Connect to an AC 110V, 60Hz
outlet only.

S-VIDEO OUT jack

S-VIDEO OUT jack

*EUR VERSION

*USA/CANADA VERSION

OPTICAL DIGITAL AUDIO OUT jack

REMOTE CONTROL

****REMOTE SELECT

1-8

EXPLODED VIEW

S10

26

x4

16

24

25

S10

x5

S9

x3

23

S6

X2

S6

X2

22

S7

S5

18

17

X2

21

S11

11

X2

S6

x2

27

NO

15

10

S7

19

28

S5

9

S2

x2

7

4

5

1

6

2

3

8

14

S1

x11

S2

x2

S4

4

S3

x4

x4

S5

x2

13

x4

S6

12

x4

x4

20

S4

x2

NO

DESCRIPTION

S1

SCREW

S2

SCREW,SPECIAL
SCREW

S3

SCREW

S4
S5

SCREW

S6

SCREW
SCREW

S7
S8

SCREW
SCREW

S9

SCREW

S10

SCREW

S11

PARTS-NO
KTB3+6F
KHD1A016
KTS3+8J
KTB3+6J
KTB3+10G
KTW3+8J 12
KTW3+12J
KTB3+8J

KTB3+10GFZ
KTB3+6JFZ

S6

x2

QT`Y

9
4

4
4
6

2
2
3
9
2KTB4+6JFZ

DESCRIPTION

1

FRONT PANEL
DOOR ORNAMENT

2
3

FIP WINDOW
SIDE BAR

4

LED INDICATOR

5
6

SENSOR WINDOW
POWER KNOB

7
8

DISPLAY KNOB

9

SUB PANEL

10

FRONT PCB ASS'Y

11

BOTTOM CHASSIS
FOOT

12
13

FOOT CUSHION
MECHA. SUPPORT

14

MECHANISM,DVD

15
16

REAR PANEL

17

PCB HOLDER

18

CUSHION

19

AV PCB ASS'Y

20

PCB BRACKET

21

POWER PCB ASS'Y

22

PCB BRACKET

23

JACK,BOARD

24

MAIN PCB ASS'Y

AC CORD BUSHING

25
26

AC CORD

27

TOP CABINET
SHEET

28
29

PARTS-NO
KKM1A106ZC26
KGR1A214M7ZK102
KGU1A244A8
KKM1A051C26
KGL1A188
KGU1A245A10
KBT1A746M7K102
KBT1A745M7K102
KGW1A298
KUP11408C

KUA1A189
BKL1A060

BHG1A171
KMH1A113

BJDTVM502/1
KKF1A210Z
KHE170
KHG1A104

KUP11390Z
KMD1A413
KOP11401CSMPS

KMD1A420
KOP11408B

BVNTFCEIE311A
KHR1A028
BJA2B043Z

KKC3B076S33
KGX1A304

QT`Y

1
1
1
2

0.17
1
1

2
1
1
1

4
4

1
1
1

2
1
1

1

1

1
1

1

1

1

1

1

1-9 1-10

2-1

SECTION 2

ELECTRICAL

CONTENTS

ELECTRICAL TROUBLESHOOTING GUIDE......................................................................2-2

1. Power (SMPS) Circuit ..............................................................................................................2-2

............................................................................................................................2-3

3. MPEG Circuit............................................................................................................................2-6

4. Front Circuit (Digitron & Key) ...............................................................................................2-7

5. RF/Servo Circuit ......................................................................................................................2-8

BLOCK DIAGRAMS..................................................................................................................2-12

1. Overall Block Diagram..........................................................................................................2-12

2. Power (SMPS) Block Diagram..............................................................................................2-13

3. RF/CD DSP/DVD DSP/DVD servo Block Diagram ..............................................................2-14

4. Audio Block Diagram............................................................................................................2-15

5. MPEG Block Diagram...........................................................................................................2-16

...........................................................................................................2-17

CIRCUIT DIAGRAMS................................................................................................................2-18

1. Power (SMPS) Circuit Diagram ............................................................................................2-18

2. DVD DSP Circuit Diagram.....................................................................................................2-20

3. Drive & RF Circuit Diagram ..................................................................................................2-22

4. MPEG Circuit Diagram ..........................................................................................................2-24

4-1. WAVEFORMS...................................................................................................................2-26

5. Audio DM & 5.1CH Circuit Diagram.....................................................................................2-28

....................................................................................................................2-30

7. DIGITRON & Key Circuit Diagram........................................................................................2-32

8. Jack Circuit Diagram.............................................................................................................2-34

PRINTED CIRCUIT DIAGRAMS............................................................................................2-36

1. MAIN P.C.BOARD...................................................................................................................2-36

2. POWER P.C.BOARD..............................................................................................................2-38

3. AV P.C.BOARD.......................................................................................................................2-40

4. FRONT P.C.BOARD

...............................................................................................................

2-42

2-2

ELECTRICAL TROUBLESHOOTING GUIDE

1. POWER (SMPS) Circuit

No LED

Is 5.2V applied
to CN62 Pin 5 ?

NO

Check R622, R623

Is 5.2V applied
to PT61 Pin 1 ?

NO

Check D601-D604

Check Q626, D609

YES

YES

Check FRONT Circuit

Check L620, R620

No 8V No 3.3V

Check Q622, Q623, R632

NO

No 5V_D, 5V_A

Is High State applied

to CN63 Pin 2 ?

YES

Check Q620, Q625, R625

Check IC67, R609

NO FLD

Is -24V applied
to CN62 Pin 3 ?

YES

END

NO

Check D625, IC62

Check IC64, D628, D621

2-3

2. u-COM Circuit
A. NO Power

AC In

Is LED On?

YES

Power On Reconnect CN61

Is LED Off ?

YES

Does bar appear

on FLD ?

YES

Does logo appear
on the screen?

YES

NO

NO

NO

Is CN61 conneted

correctly?

NO

Check L620, R620 Check Power Circuit

Is oscillation of
X501 normal?

Are IC503 Pin 14, 28
and 29 normal?

YES

YES

YES

NO

NO

Is 5.2V applied
to CN61 Pin 12 ?

YES

Check FRONT Circuit

Check the oscillation

NO

OK

The waveform on

A[00:21] and D[00:15] of

IC501 normal?

YES

Are IC506 Pin 7, 8
normal?

YES

Replace Main B/D

NO

NO

Check short

YES

Replace IC501 or IC503

2-4

B. Audio abnormal

D. Open/Close abnormal

Check the

connection of P5901.

Check IC501 Pins 13, 14.

Check Audio jack.

YES (If OK)

YES

NO

NO

YES

YES (If OK)

YES

YES (If OK)

YES (If OK)

YES (If OK)

Check PLL FC of MPEG part.

Refer to Audio part.

Refer to MPEG part.

Replace B/D.

Check Front.

Reconnect it.

Refer to SERVO part.

Check the connection of MD.

AUDIO ABNORMAL

OPEN/CLOSE ABNORMAL

C. Video abnormal

Check Video jack.

YES (If OK)

YES (If OK)

YES (If OK)

YES (If OK)

Refer to Video part.

Refer to Encoder part.

Refer to MPEG part.

Replace B/D.

VIDEO ABNORMAL

2-5

E. Picture abnormal

Check the disc.

If OK

YES (If OK)

YES (If OK)

Refer to Servo part

Check PLL IC of MPEG part

Check DSP

Check MPEG

YES (If OK)

Replace B/D

PICTURE ABNORMAL

F. Disc Error

Check Disc

YES (If OK)

YES (If OK)

Refer to Servo part

Replace B/D

DISC ERROR

2-6

Power is on

Does LG Logo appear

on the screen?

Does the

moving picture of the DVD Disc

play on the screen

normally?

Is MPEG data signal normal?

Is error signal normal?

Is MPEG data signal normal?

Is Clock normal?

Does the audio

sound output from MPEG

decoder?

Does the

moving picture of the video

CD play on the screen

normally?

Does the audio sound

output normally?

END

Check power & clock.

Check CD/DVD DSP output

signal.

Check MPEG Decoder input

signal.

Check CD/DVD DSP output

signal.

Check MPEG Decoder input

signal.

Check CD/DVD DSP output

signal.

Check MPEG Decoder input

signal.

Check clock signal

Check clock signal

YES

YES

YES

YES

YES

YES

YES

YES

YES

YES

NO

NO

NO

OK

OK

OK

OK

NO

NO

NO

NO

NO

3. MPEG Circuit

OPTION

If included VCD function.

2-7

4. Front Circuit (Digitron & Key)

START

Is LED On?

YES

Power On Check Power Circuit.

Is LED Off ?

YES

Does bar appear

on FLD ?

YES

Does all the buttons

work normally?

NO

NO NO

NO

NO

Is 5.2V applied
to CN61 Pin 12 ?

Is HIGH State appear

on IC91 Pin 2 ?

Does "Main Error"

appear on FLD?

Check waveform of

IC91 Pin 14

Check R904, 906, 909, 910,

R911, 916, 919, 924

NO

YES

YES

YES

YES

NO

NO

Check L901

Check Q901, Q904, D902

Check the oscillation of X901

and Replace IC91 or X901

Check Power Circuit

Check S902-S907, S909

Check Solder

YES

Does remote control

work normally?

YES

NO NO

Does waveform of

IC92 Pin 1 appear?

YES YES

Is IC91 Pin 24 connected

to IC92 Pin 1 ?

YES

Replace IC91OK

NO

Is 5V applied to
IC92 Pin 3 ?

Replace IC92

Check Solder

NO