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Extracted text from Nad L 55 Service Manual 2 (Ocr-read)
Page 1
SERVICE MANUAL
L55
DVD/VIDEO CD/CDPLAYER DVD/VIDEO CD/CD
PLAYER L55
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1-2
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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 MANUFACTURERS 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 INSUCH 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 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 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
PRODUCTS 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. VOLTMETER
PLACE THIS PROBE
ON EACH EXPOSED
METAL PART
GOOD EARTH GROUND
SUCH AS THE WATER
PIPE. CONDUIT. ETC
10 WATT
1500 OHM 0.15uF
2-30 2-31
6. µ-com/ Expander
FLASH ROM DRAM
MAIN CPU
EXPANDER
EEPROM
CPLD
OPEN OPEN
'00 03. 28 R10537B DVD3351ND'S
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Open, Close Error
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