NAD-T748-avr-sm 维修电路原理图.pdf

LAUNAMECIVRESAV Surround Sound ReceiverT748AV Surround Sound ReceiverT748RadioFans.CN 收音机爱 好者资料库PRODUCT SAFETY SERVICING GUIDELINES1-3* General Servicing Precautions* Insulation checking prodedure* Electrostatically Sensitive DevicesWSECTION 1 SUMMARYCONTENTSSERVICING PRECAUTIONS1-4SPECIFICATIONS1-5DISASSEMBLY1-6PRINCIPAL PART LOCATION1-7EXPLODED VIE1-8.1-2RadioFans.CN 收音机爱 好者资料库PRODUCT SAFETY SERVICING GUIDELINES CAUTION : DO NOT ATTEMPT TO MODIFY THIS PRODUCT INANY WAY. NEVER PERFORM CUSTOMIZED INSTALLATIONSWITHOUT MANUFACTURERS 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 THEPRODUCTS 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.1-3SERVICING PRECAUTIONSCAUTION : Before servicing the A/V Receiver covered by thisservice data and its supplements and addends, read and follow theSAFETY PRECAUTIONS. NOTE : if unforeseen circumstancescreate conflict between the following servicing precautions and anyof the safety precautions in this publication, always follow the safetyprecautions.Remember Safety First:General Servicing Precautions1. Always unplug the A/V Receiver AC power cord from the ACpower source before:(1) Removing or reinstalling any component, circuit board,module, or any other assembly.(2) Disconnecting or reconnecting any internal electrical plug orother electrical connection.(3) Connecting a test substitute in parallel with an electrolyticcapacitor.Caution : A wrong part substitution or incorrect polarity installationof electrolytic capacitors may result in an explosion hazard.2. Do not spray chemicals on or near this A/V Receiver or any of itsassemblies.3. Unless specified otherwise in this service data, clean electricalcontacts by applying an appropriate contact cleaning solution tothe contacts with a pipe cleaner, cottontipped swab, orcomparable soft applicator.Unless specified otherwise in this service data, lubrication ofcontacts is not required.4. Do not defeat any plug/socket B+ voltage interlocks with whichinstruments covered by this service manual might be equipped.5. Do not apply AC power to this A/V Receiver and/or any of itselectrical assemblies unless all solid-state device heat sinks arecorrectly installed.6. Always connect test instrument ground lead to the appropriateground before connecting the test instrument positive lead. Alwaysremove the test instrument ground lead last.Insulation Checking ProcedureDisconnect the attachment plug from the AC outlet and turn thepower on. Connect an insulation resistance meter(500V) to theblades of the attachment plug. The insulation resistance betweeneach 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, Inputterminals, Earphone jacks, etc.Electrostatically Sensitive (ES) DevicesSome semiconductor (solid state) devices can be damaged easily bystatic electricity. Such components commonly are calledElectrostatically Sensitive (ES) Devices. Examples of typical Esdevices are integrated circuits and some field effect transistors andsemiconductor chip components.The following techniques should be used to help reduce theincidence of component damage caused by static electricity.1. Immediately before handling any semiconductor component orsemiconductor-equipped assembly, drain off any electrostaticcharge on your body by touching a known earth ground.Alternatively, obtain and wear a commercially availabledischarging wrist strap device, which should be removed forpotential shock reasons prior to applying power to the unit undertest.2. After removing an electrical assembly equipped with ES devices,place the assembly on a conductive surface such as aluminumfoil, to prevent electrostatic charge buildup or exposure of theassembly.3. Use only a grounded-tip soldering iron to solder or unsolder ESdevices.4. Use only an antistatic solder removal device. Some solderremoval devices not classified a “anti-static” can generateelectrical charges sufficient to damage ES devices.5. Do not use freonpropelled chemicals. These can generateelectrical charge sufficient to damage ES devices.6. Do not remove a replacement ES device from its protectivepackage until immediately before you are ready to install it. (Mostreplacement ES devices are packaged with leads electricallyshorted together by conductive foam, aluminum foil, orcomparable conductive material).7. lmmediately before removing the protective material from theleads of a replacement ES device, touch the protective material tothe chassis or circuit assembly into which the device will beinstalled.Caution : Be sure no power is applied to the chassis or circuit, andobserve all other safety precautions.8. Minimize bodily motions when handing unpackaged replacementES devices. (Normally harmless motion such as the brushingtogether of your clothes fabric or the lifting of your foot from acarpeted floor can generate static electricity sufficient to damagean ES device.)1-4Amplifier SectionFM Tuner Section(Without notes 100.1MHz, 60dB)Output Power(Front):egnaR gn i nuT:no i taR C.T.Ft s zHK05:C zHM0.801 - zHM5.78 ,mumi n im l ennahc rep SMR st taw 08epspet s zHK001:HA mor f smho 8 otn i nev i rd s l ennahc htobs20Hz to 20KHz with no more than 0.08% Bd 54 : C : o i taR no i sserppuS MAno i t rot s id c i nomrah latotAH : 45 dBSurround Output Power (0.08% THD, 1KHz, 8 ohms): : )zHK1(no i t rot s iD c i nomraH latoT) tnorF( t taW 54 + 54 %8.0 : onoM) retneC( t taW 54%0.1 : oeretS) r ruS( t taW 54 + 5445 + 45 Watt (Back Surr)Freqency Response : 50Hz - 13KHz, +3/-3dBTotal Harmonic Distortion (Front):Bd03 : C : )zHK1(no i tarapeS oeretS)zHK1 , st taW 54 ta( %80.0Bd03 : HA Audio input Sensitivity/Impedance : :o i taR es ioN-ot- lang iSsmhoK 74/Vm 052 : en i L * Mono : 60dBOutput Level / Impedance* REC : 250 mV/2.2KohmsAM Tuner Section:egnaR gn i nuT : esnopseR ycneqerF)spet s zHK9(zHK0261-zHK225:CBd3- /3+ , zHK001 - zH02 : en i L *AH:520KHz-1710KHz(10KHz steps)Signal-to-Noise Radio : 1 WattBd55 : yt i v i t i sneS e lbasU)A-FHI ( Bd 58 : en i L *Total Harmonic Distortion : 1.0%Bd53 : o i taR es ioN-ot- lang iSlor tnoC enoTBASS : +/- dB at 100HzTREBLE : +/- dB at 10KHzGeneralPower Requirements : Digital audio SectionC : AC230V, 50HzzH06 ,V021CA : HA: ycneqerF gn i e lpmaS32KHz, 44.1KHz, 48KHz, 96KHz, 192KHzPower Consumption : C : 2.0A AH : 4.5A latoT ,1 x deht iwsnu : ste l tuO CAecnadepmI / l eveL tupnI lat ig iD100W max.(1A)3 x 761 x 534 : )D x H x W(sno i snemiDsmho 57/p-pV 5.0 : la i xaoC97gK5.11 : ) ten( thg i eWmBd12- mBd51- : lac i tpOVideo SectionInput Level/Impedance : 1.0Vp-p/75ohmsOutput Level/Impedance : 1.0Vp-p/75ohms*Linemeans Source 14, Front, MP* Improvements may result in specifications and features changing without notice* Illustrations may differ slightly from production models.1-5SPECIFICATIONSFactory ResetThe select AM mode, then press/hold “listening mode” button.DISASSEMBLYREMOVAL OF FRONT PANEL1-6PRINCIPAL PART LOCATION1-71-8T748AH EXPLODED VIEW PARTS LIST10CABINET,TOPCKC1A188B22FRONT PCB ASSY2327242526171819202221111213141615PANEL,REARBRACKETRUBBER,FOOTFOOTCOP12370BCHG1A297CKL1A086CKF2A445ZK1CMD1A674BRACKET8954376FUNCTION KNOB ASSYCOVER,JACKPANEL,ALPOWER KNOB ASSYNO21VOLUME KNOB ASSYDESCRIPTIONCKM1A208XC64CBT1A1103ZACGK2A126ZACMD2A563CGR1A476B29CGK1A145ZAPARTS NO 1111441 1121111Q,ty127-1COP12370-128MAIN PCB ASSYCOP12372B11111INPUT PCB ASSY29COP12371C1WINDOW ,FIPCGU1A434Z111CGW2A475RBB29PANEL,FRONT1REMARK1KNOB,SOURCECBT1A1104B2921CHASSIS ,BOTTOMCUA1A3271SUPPORT,PCB 31CRE1A0731HEAT SINKCMY1A369BRACKET,PCBCMD1A7342BRACKET , FANCMD1A694KNOB,VOLUMECBN1A216CAP,VOLUMECGK1A145C64KNOB,POWERCBT1A1103B291INDICATOR,POWERCGL1A280Z1CAP,FUNCTIONCGK1A126C64KNOB,FUNCTIONCBT1A1102B29HDMI PCB ASSY1COP12374CS1S5S4S3NO54CTB3+8JFZRSCREWSCREWSCREWCTB4+6FFZRCHD1A012RCTW3+12JR1446DESCRIPTIONPARTS NO.Q,tySCREWCTWS3+10GR2S6CHD3A012R8S7SCREW,SPECIALCHD1A036R4S8SCREW,TRANSCHD1A023R4S9S10S1113CTB3+6FFZRSCREW1FAN,MOTOT(60*60*25)1FAN,MOTOR(80*80*25)1CFNRDH8025SCFNRDM6025SCWZPM5003TW91A2P WIRE ASSY1111 11 11 111COP12370-2COP12370-3COP12370-4COP12370-5COP12370-6COP12370-7HOLDER , PCBCHE1704BRACKET , FANCMD1A5061TRANS,POWER11SCREW,SPECIALCHD1A036FZR2SCREW,SPECIALSCREW,SPECIALS121CTW3+8JRSCREW28-128-21COP12370-8COP12372-1COP12372-2SUB PCB ASSY31COP12373C131-131-231-3COP12373-111131-41COP12373-2COP12373-3COP12373-4301129-129-2COP12371-1COP12371-211CLT5V061ZU27-227-327-427-527-627-727-81-91-10S1S1S1S1S1S3S1S1S5S3S1S3S1S1S4S4S1S10S11S11S11S11S1S11S8S12S1S6S1S7S11S1S1S1X5S5S1S1S1S9S12S1S13125467869181927-127-527-227-427-39161710251312111520212324221427-727-827-628-128-229-130 31-131-231-331-429-2T748AH EXPLODED VIEW1-11T748C EXPLODED VIEW PARTS LIST10CABINET,TOPCKC1A188B22/G39FRONT PCB ASSY2327242526171819202221111213141615PANEL,REARBRACKETRUBBER,FOOTFOOTCOP12370BCHG1A297CKL1A086CKF1A445ZK1CMD1A674BRACKET8954376FUNCTION KNOB ASSYCOVER,JACKPANEL,ALPOWER KNOB ASSYNO21VOLUME KNOB ASSYDESCRIPTIONCKM1A208XC64CBT1A1103ZACGK2A126ZACMD2A563CGR1A476B29CGK1A145ZAPARTS NO 1111441 1121111Q,ty127-1COP12370-128MAIN PCB ASSYCOP12372B11111INPUT PCB ASSY29COP12371B1WINDOW ,FIPCGU1A434Z111CGW2A475RBB29PANEL,FRONT1REMARK11KNOB,SOURCECBT1A1104B2921CHASSIS ,BOTTOMCUA1A3271SUPPORT,PCB 31CRE1A0731HEAT SINKCMY1A369BRACKET,PCBCMD1A7342BRACKET , FANCMD1A694KNOB,VOLUMECBN1A216CAP,VOLUMECGK1A145C64KNOB,POWERCBT1A1103B291INDICATOR,POWERCGL1A280Z1CAP,FUNCTIONCGK1A126C64KNOB,FUNCTIONCBT1A1102B29HDMI PCB ASSY1COP12374BS1S5S4S2S3NO54CTB3+8JFZRSCREWSCREWSCREWCTB4+6FFZRCHD1A012RCTW3+12JR1446DESCRIPTIONPARTS NO.Q,tySCREWCTWS3+10GR2S6CHD3A012R8S7SCREW,SPECIALCHD1A036R4S8SCREW,TRANSCHD1A023R4S9S10S1113CTB3+6FFZRSCREW1FAN,MOTOT(60*60*25)1FAN,MOTOR(80*80*25)1CFNRDH8025SCFNRDM6025SCWZPM5003TW91A2P WIRE ASSY1111 11 11 111HOLDER , PCBCHE1704BRACKET , FANCMD1A5061TRANS,POWER11CTB3+8JFCSCREW,SPECIALCHD1A036FZR2SCREW,SPECIALSCREW,SPECIAL10S121CTW3+8JRSCREW28-128-21COP12372-1COP12372-2SUB PCB ASSY31COP12373B131-131-231-3COP12373-111131-41COP12373-2COP12373-3COP12373-4301127-227-327-427-527-627-727-8COP12370-2COP12370-3COP12370-4COP12370-5COP12370-6COP12370-7COP12370-829-1COP12371-1129-2COP12371-21CLT5V061ZESCREW1-121-13S1S1S1S1S1S3S1S1S5S3S1S3S1S1S4S4S1S10S11S11S11S11S1S11S8S12S1S6S1S7S11S1S1S1S2S2X