NAD L76 Service Manual

Also see for L 76: Specification sheet Owner's manual

Contents

NAD L76 Service Manual Manual pdf 3 page image

1-4PRODUCT SAFETY SERVICING GUIDELINESCAUTION : DO NOT ATTEMPT TO MODIFY THIS PRODUCT INANY WAY. NEVER PERFORM CUSTOMIZED INSTALLATIONSWITHOUT MANUFACTURER’S APPROVAL. UNAUTHORIZEDMODIFICATIONS WILL NOT ONLY VOID THE WARRANTY, BUTMAY LEAD TO YOUR BEING LIABLE FOR ANY RESULTINGPROPERTY DAMAGE OR USER INJURY.SERVICE WORK SHOULD BE PERFORMED ONLY AFTER YOUARE THOROUGHLY FAMILIAR WITH ALL OF THE FOLLOWINGSAFETY CHECKS AND SERVICING GUIDELINES. TO DOOTHERWISE, INCREASES THE RISK OF POTENTIAL HAZARDSAND INJURY TO THE USER.WHILE SERVICING, USE AN ISOLATION TRANSFORMER FORPROTECTION FROM AC LINE SHOCK.SAFETY CHECKSAFTER THE ORIGINAL SERVICE PROBLEM HAS BEENCORRECTED. A CHECK SHOULD BE MADE OF THEFOLLOWING.SUBJECT : FIRE & SHOCK HAZARD1. BE SURE THAT ALL COMPONENTS ARE POSITIONED INSUCH A WAY AS TO AVOID POSSIBILITY OF ADJACENTCOMPONENT SHORTS. THIS IS ESPECIALLY IMPORTANTON THOSE MODULES WHICH ARE TRANSPORTED TO ANDFROM THE REPAIR SHOP.2. NEVER RELEASE A REPAIR UNLESS ALL PROTECTIVEDEVICES SUCH AS INSULATORS, BARRIERS, COVERS,SHIELDS, STRAIN RELIEFS, POWER SUPPLY CORDS, ANDOTHER HARDWARE HAVE BEEN REINSTALLED PERORIGINAL DESIGN. BE SURE THAT THE SAFETY PURPOSEOF THE POLARIZED LINE PLUG HAS NOT BEEN DEFEATED.3. SOLDERING MUST BE INSPECTED TO DISCOVER POSSIBLECOLD SOLDER JOINTS, SOLDER SPLASHES OR SHARPSOLDER POINTS. BE CERTAIN TO REMOVE ALL LOOSEFOREIGN PARTICLES.4. CHECK FOR PHYSICAL EVIDENCE OF DAMAGE ORDETERIORATION TO PARTS AND COMPONENTS. FORFRAYED LEADS, DAMAGED INSULATION (INCLUDING ACCORD). AND REPLACE IF NECESSARY FOLLOW ORIGINALLAYOUT, LEAD LENGTH AND DRESS.5. NO LEAD OR COMPONENT SHOULD TOUCH A RECEIVINGTUBE OR A RESISTOR RATED AT 1 WATT OR MORE. LEADTENSION AROUND PROTRUDING METAL SURFACES MUSTBE AVOIDED.6. ALL CRITICAL COMPONENTS SUCH AS FUSES,FLAMEPROOF RESISTORS, CAPACITORS, ETC. MUST BEREPLACED WITH EXACT FACTORY TYPES, DO NOT USEREPLACEMENT COMPONENTS OTHER THAN THOSESPECIFIED OR MAKE UNRECOMMENDED CIRCUITMODIFICATIONS.7. AFTER RE-ASSEMBLY OF THE SET ALWAYS PERFORM ANAC LEAKAGE TEST ON ALL EXPOSED METALLIC PARTS OFTHE CABINET, (THE CHANNEL SELECTOR KNOB, ANTENNATERMINALS. HANDLE AND SCREWS) TO BE SURE THE SETIS SAFET TO OPERATE WITHOUT DANGER OF ELECTRICALSHOCK. DO NOT USE A LINE ISOLATION TRANSFORMERDURING THIS TEST USE AN AC VOLTMETER, HAVING 5000OHMS PER VOLT OR MORE SENSITIVITY, IN THEFOLLOWING MANNER; CONNECT A 1500 OHM 10 WATTRESISTOR, PARALLELED BY A .15 MFD, 150V AC TYPECAPACITOR BETWEEN A KNOWN GOOD EARTH GROUND(WATER PIPE, CONDUIT, ETC.) AND THE EXPOSEDMETALLIC PARTS, ONE AT A TIME.MEASURE THE AC VOLTAGE ACROSS THE COMBINATIONOF 1500 OHM RESISTOR AND .15 MFD CAPACITOR.REVERSE THE AC PLUG AND REPEAT AC VOLTAGEMEASUREMENTS FOR EACH EXPOSED METALLIC PART.VOLTAGE MEASURE MUST NOT EXCEED 75 VOLTS R.M.S.THIS CORRESPONDS TO 0.5 MILLIAMP AC ANY VALUEEXCEEDING THIS LIMIT CONSTITUTES A POTENTIALSHOCK HAZARD AND MUST BE CORRECTED IMMEDIATELY.SUBJECT : GRAPHIC SYMBOLSSUBJECT : TIPS ON PROPER INSTALLATION1. NEVER INSTALL ANY PRODUCT IN A CLOSED-IN RECESS,CUBBYHOLE OR CLOSELY FITTING SHELF SPACE. OVEROR CLOSE TO HEAT DUCT, OR IN THE PATH OF HEATEDAIR FLOW.2. AVOID CONDITIONS OF HIGH HUMIDITY SUCH AS:OUTDOOR PATIO INSTALLATIONS WHERE DEW IS AFACTOR, NEAR STEAM RADIATORS WHERE STEAMLEAKAGE IS A FACTOR, ETC.3. AVOID PLACEMENT WHERE DRAPERIES MAY OBSTRUCTREAR VENTING. THE CUSTOMER SHOULD ALSO AVOID THEUSE OF DECORATIVE SCARVES OR OTHER COVERINGSWHICH MIGHT OBSTRUCT VENTILATION.4. WALL AND SHELF MOUNTED INSTALLATIONS USING ACOMMERCAL MOUNTING KIT MUST FOLLOW THE FACTORYAPPROVED MOUNTING INSTRUCTIONS A PRODUCTMOUNTED TO A SHELF OR PLATFORM MUST RETAIN ITSORIGINAL FEET (OR THE EQUIVALENT THICKNESS INSPACERS) TO PROVIDE ADEQUATE AIR FLOW ACROSSTHE BOTTOM, BOLTS OR SCREWS USED FOR FASTENERSMUST NOT TOUCH ANY PARTS OR WIRING. PERFORMLEAKAGE TEST ON CUSTOMIZED INSTALLATIONS.5. CAUTION CUSTOMERS AGAINST THE MOUNTING OF APRODUCT ON SLOPING SHELF OR A TILTED POSITION,UNLESS THE PRODUCT IS PROPERLY SECURED.6. A PRODUCT ON A ROLL-ABOUT CART SHOULD BE STABLEON ITS MOUNTING TO THE CART. CAUTION THECUSTOMER ON THE HAZARDS OF TRYING TO ROLL A CARTWITH SMALL CASTERS ACROSS THRESHOLDS OR DEEPPILE CARPETS.7. CAUTION CUSTOMERS AGAINST THE USE OF A CART ORSTAND WHICH HAS NOT BEEN LISTED BY UNDERWRITERSLABORATORIES, INC. FOR USE WITH THEIR SPECIFICMODEL OF TELEVISION RECEIVER OR GENERICALLYAPPROVED FOR USE WITH T.V.’S OF THE SAME ORLARGER SCREEN SIZE.8. CAUTION CUSTOMERS AGAINST THE USE OF EXTENSIONCORDS, EXPLAIN THAT A FOREST OF EXTENSIONSSPROUTING FROM A SINGLE OUTLET CAN LEAD TODISASTROUS CONSEQUENCES TO HOME AND FAMILY.THE LIGHTNING FLASH WITH ARROWHEAD SYMBOL, WITHIN ANEQUILATERAL TRIANGLE, IS INTENDED TO ALERT THE USER TO THEPRESENCE OF UNINSULATED “DANGEROUS VOLTAGE” WITHIN THEPRODUCT’S ENCLOSURE THAT MAY BE OF SUFFICIENT MAGNITUDE TOCONSTITUTE A RISK OF ELECTRIC SHOCK.THE EXCLAMATION POINT WITHIN AN EQUILATERAL TRIANGLE ISINTENDED TO ALERT THE USER TO THE PRESENCE OF IMPORTANTOPERATING AND MAINTENANCE (SERVICING) INSTRUCTIONS IN THELITERATURE ACCOMPANYING THE APPLIANCE.