Elenberg LD-750 Service manual

Service manual

LD-750 Portable DVD

CONTENTS

SECTION 1…………SUMMARY

SECTION 2…………ELECTRICTAL

SECTION 3…………REPLACEMENT PART LIST

SECTION 1

SUMMARY

CONTENTS

PRODUCT SAFETY SERVICING GUIDELINES FOR VIDEO

PRODUCTS………………………………………………………4

SERVICING PRECAUTIONS ……………………………………7

FUNCTION FEATURES …………………………………………11

CAUTION: DO NOT ATTEMPT TO MODIFY THIS PRODUCT IN ANY WAY,NEVER PERFORM CUSTOMIZED

INSTRALLATIONS 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 OTHERVISE,
INCREASES THE RISK OF PRTENTIAL 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 CORRCTED.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 AVOIO POSSIBILITY
OF ADJACENT COMPONENT SHORTS. THIS IS ESPECIALLY IMPORTANT ON THOSE MODULFW WHICH
ARE TRANSPORTED TO AND FROM THE REPAIR SHOP.

2. NEVER RELEASE A REPAIR UNLESS ALL PROTECTIVE DEVICES SHCH AS INSULATORS, BARRIERS,
COVERS, SHIELDS, STRAIN RELIEFS, POWER SUPPLY CORDS,AND OTHER HARDWARE HAVE BEEN
REINSTRLLED 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 FORING 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 RECIVING TUBE OR A RESISTOR RATED AT 1 WATT
OR MORE. LEAD TENSION AROUND PROTRUNING 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 SAFE 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
REFEAT A.C. VOLTAGE MEASUREMENTS FOR EACH EXPOSEDMETALLIC PART. VOLTAGE MEASURED
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

THE LIGHTNING FLASH WITH APROWHEAD SYMBOL.WITHIN AN EQUILATERAL TRIANGLE,

IS INTENDED TO ALERT THE SERVICE PERSONNEL TO THE PRESENCE OF UNINSULATED〝DANGEROUS
VOLTAGE〞 THAT MAY BE OF SUFFICIENT MAGNITUDE TO CONSTITITE A RISK OF ELECTRIC SHOCK.

THE EXCLAMATION POINT WITHIN AN EQUILATERAL TRIANGLE IS INTENDED TO ALERT

THE SERVICE PERSONNEL TO THE PRESENCE OF IMPORTANT SAFETY INFORMATION IN SERVICE
LITERATURE.

SUBJECT: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 T.V. RECEIVERS IS
THE PICTURE TUBE. HOWEVER,THIS TUBE DOES NOT EMIT X-RAYS WHEN THE HIGH VOLTAGE
IS AT THE FACTORY SPECIFIED LEVEL. THE PROPER VALUE IS GIVEN IN THE APPLICABLE
SCHEMATIC. OPERATION AT HIGHER VOLTAGES MAY CARSE 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 C.R.T. ANODE CONNECTORS MUST BE USED. DEGAUSSING SHIELDS

ALSO SERVE AS X-RAY SHIELD IN COLOR SETS, ALWAYS RE-INSTALL THEM.

3. IT IS ESSNTIAL THAT SERVICE PERSONNEL HAVE AVAILABLE AN ACCURATE AND RELIABLE HIGH

VOLTAGE METER. THE CALIBRA TION OF THE METER SHOULD BE CHECKED PERIODICALLY AGAINST
A REFERENCE STANDARD, SUCH AS THE ONE AVAILABLE AT YOUR DISTRIBUTOR.

4. WHEN THE HIGH VOLTAGE CIRCUITRY IS OPERATING PROPERLY THERE IS NO POSSIBILITY OF

AN X-RADIATION PROBLEM. EVERY TIME A COLOR CHASSIS IS SERVICED. THE BRIGHTNESS
SHOULD BE RUN UP AND DOWM WHILE MONITORING THE HIGH VOLTAGE WITH A METER TO BE
CERTAIN THAT THE HIGH VOLAGE DOES NOT EXCEED THE SPECIFIED VALUE AND THAT IT IS
REGULATING CORRECTLY, WE SUGGEST THAT YOU AND YOUR SERVICE ORGANIZATION REVIEW
TEST PROCEDURES SO THAT VOLAGE REGULATION IS ALWAYS CHECKED AS A STANDARD SERVICING
PROCEDURE. AND THAT THE HIGH VOLTAGE READING BE RECORDER ON EACH CUSTOMER’S
INVOICE.

5. WHEN TROUBLESHOOTING AND MAKING TEST MEASUREMENTS IN A PRODUCT WITH A PROBLEM OF
EXCESSIVE HIGH VOLTAGE, AVOID BEING UNNECESSARILY CLOSE TO THE PICTURE TUBE AND
THE HIGH VOLTAGE SUPPLY. DO NOT OPERATE THE PRODUCT LONGER THAN IS NECESSARY TO
LOCATE THE CARSE OF EXCESSIVE VOLTAGE.

6. REFER TO HV. B+ AND SHUTDOWN ADJUSTMENT PROCEDURES DESCRIBED IN THE APPROPRIATE
SCHEMATIC AND DIAGRAMS (WHERE USED).

SUBJECT:IMPLOSION

1. ALL DIRECT VIEWED PICTURE TUBES ARE EQUIPPED WITH AN INTEGRAL IMPLOSION PROTECTION
SYSTEM. BUT CARE SHOULD BE TAKEN TO AVOID DAMAGE DURING INSTALLATION, AVOID
SCRATCHING THE TUBE. IF SCRATCHED REPLACE IT.

2. USE ONLY RECOMMENDED FACTORY REPLACEMENT TUBES.

SUBJECT:TIPS ON PROPER INSTALLATION

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 PALCEMENT 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 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 PABTS 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 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.

SERVICING PRECAUTIONS

CAUTION:Before servicing the PORTABLE DVD 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 precartions and any of the safety precautions in this

publications, always follow the safety precautions.

Remembers Safety First:

General Servicing Precautions

1. Always unplug the PORTABLE DVD AC power cord from the AC power source

before

(1) Removing or reinstalling any component,circuit board,module,or

any other assembly.

(2) Disconnection or reconnecting any internal electrical plug or

other electrical conncetion.

(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 PORTABLE DVD 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 PORTABLE DVD and/or any of its eledtrical

assemblies unless all solid-state device heat sinks are correctly

installed.

6. Always connect test instrument ground lead to the appropriate ground

before connection 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.

Note1: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 knowm earch ground.Alternatively,obtain and

wear a commercially available discharging wrist wrist strap device,

which shoule 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 grouned-tip soldering iron to solder orunsolder ES devices.

4. Use only an anti-static 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 freon-propelled chemicals. These can generate electrical

charge sufficient to damage ES devices.

6. Do not remove a replancement 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.)

FUNCTION FEATURES

High Quality Audio and Video

Excellent Sound
Dolby Decoder delivers great sound.

AV IN

External Audio, Video input can be connected to most external AV
sources.

AV Out

Audio output and video output

Advanced Playing Function

Compatibility

Compatible with DVD, CD , Picture CD, DIVX discs, etc.

ON-Screen Display

You can choose English or Russian as the On-screen Display language.

Particular Performance:

Multi-speed, fast forward, fast backward and
slow forward, slow backward.

Search By Time

Search for a certain time on a disc.

Last Memory Playback

Memorizes the stopped playback track and continues playing the
disk from this spot when power is applied to the unit.

Special Functions

Supports screen aspect ratio changing, zooming in or out, multilanguage
caption, multi-angle viewing.

Other Special Functions

High Resolution

MPEG-2 decoding format achieves more than 500 lines of horizontal
resolution.

Power Adapter Switch

Automatically adapts to voltage requirements in U.S and other
countries.

Region code information

DVD players and discs are coded by region. These regional codes
must match. If the codes don’t match, the disc cannot be played.
This player’s code is region 5.

MAIN FEATURES

MAIN FEATURES

SECTION 2

ELECTRICAL

CONTENTS

LCD PART ………………………………………………………14

ELECTRICAL TROUBLE SHOOTING GUIDE………………………19

CIRCUIT DIAGRAMS ……………………………………………22

DETAILS AND WAVEFORMS ON SYSTEM TEST AND DEBUGGING....29

PRINTED CIRCUIT DIAGRAMS …………………………………35

LCD PART

1)Power measuring

Measure each power after power supply.

C72:-13V, C71:+17V,C95（+）:+7.5V,C105(+):+5V,C48(+):3.3V

2)VCOM waveform sdjustment

Adjust the VCOM level while changing the VR1 as below waveform by using the scope
in the C91.

LCD TROUBLE SHOOTING GUIDE(1/2)

LCD TROUBLE SHOOTING GUIDE(2/2)