NAD-4300-tun-sm 维修电路原理图.pdf
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1、NADSERVICE_MANUAL-aMONITORSERIES4300STEREOTUNERRadioFans.CN 收音机爱 好者资料库CNAD4300SERVICEMANUALNOTE:This manual coversallversions.A:U.S.A.Al:CanadaB:U.K.Bi:AustrahaC:EUROPEandothersCl:W-GermanyTABLEOFCONTENTSPAGELOCATIONMAP2SPECIFICATION3INTERNALVIEW4SUGGESTED INSTRUMENTATiONHOOKUP5FMALIGNMENTS6-9AMALIG
2、NMENTS101lWIRiNG DiAGRAM12-13P.C.B.LAYOUTDIAGRAM1415SCHEMATICDIAGRAM16-17EXPLODEDVIEWPARTSLIST18-19EXPLODEDVIEW20ELECTRICALPARTSLIST21-23RadioFans.CN 收音机爱 好者资料库AMTuner SectionUsablesensitivity.Selectivity.Imagerejection.Mono,30dBTHDN:Mono,50dBS/N:Stereo,50dBS/N:Mono,60dBS/N:Stereo,60dBS/N:Alternatec
3、hannel:Adjacentchannel:Mono:Stereo:Mono:Stereo:AllversionsexceptUSA.50sec.de-emphasis0.83tV1.3V14.5,uV3.2tV48IN250jIV/meter.55dB.at9kHz45dB.USAversiononly.75isec.0.8.zV1.OpVl3pV2.51iV42iN43.5x8.7x29.3cm.17.1x3.4x11.51n.4.55 Kg./lOIb.5.75Kg.112lb.10 oz.50/60Hzat110, 120,220or240VAC.24W.REARPANEL1.AMR
4、odAntenna5.OutputJacks.2.AMAntennaTerminals.6.ACConvenienceOutlet(notinU.K.model).3.FMAntennaInput.7.ACLineCord.4.OutputLevel Control.0C312SPECIFICATIONSFMTunerSectionInputsensitivity(3002)Capture ratio at25,45&65dBf.AMrejection.SelectivityImagerejection.R.F.intermodulation.I.F.rejection.SCArejectio
5、n.Pilotsuppression(19+38kHz).THDat100%modulation,S/Nratio,A-weighted, 65dBf.Frequencyresponse,15-15kHz.Stereo separation(FMNRoff),FRONTPANEL1.Power.2.StationPre-sets.3.MemoryEnter.4.TuningDisplay.5.FMStereoIndicator.6.IFNarrowIndicator.45767.AM/FM.8.IFNarrow.9.FMNROft.10.Mono.11. Tuning.70dB.76dB.8d
6、B.110dB.73dB.102dB.80dB.69dB.1kHz0.08%0.07%84dB.77dB.100Hz-6kHz0.15%0.35%70rIB.76dB.8dB.110dB.73dB.102dB.80dB.72dB.1kHzlOOHz-6kHz0.07%0.15%0.05%0.35%85dB.78dB.0.5dB.50dB.35dB.250jIV/meter.()60dB.at10kHz45dB.0.5dB.1kHz:50dB.3OHz-l5kHz:35dB.NADtuNiNGMonriorSenesStereoTuner 4300rIErueseILJ.IIIOMSTENE.)
7、FMNARFOWOFF.o;LL_-IFNA000WPhysicalSpecificationsDimensions(widthxheightxdepth)NetweightShippingweightPowerrequirements11234567891011()3INTERNALVIEW40()FMALIGNMENTNECESSARY INSTRUMENTATIONFMGenerator(lessthan0.05%THD.)StereoModulator(lessthan;0.05%THD.,more than50dBSep.)AudioGenerator(notnecessayifFM
8、Generatorhasbuilt-insweep,e.g.,SOUNDTECHNOLOGYST 1000AandSTiO2OA)ACVTVMs(oronewithaLeftRightswitch)THDAnalyzer(resolutionlessthan0.1%)Oscilloscope(5mVorbettersensitivity,Xinputcapability)FrequncyCounterVOMorDMM(highimpedance,mustreadinmV)75ohmDummyAntennaIMPORTANT1)Beforealignments commence,releaseI
9、FNARROWandMONOswitches(out),SwitchFM NRoff(in).2)IFFMGeneratorisnotsynthesizer-type,besureto checkitsfrequencywithFREQcounterwhen adjustingdetectorandmultiplexdecodercircuits.A.SYNTHESIZER FREQUENCY1.ConnectFrequencyCounter betweenTP-104andground.2.Tune to98MHz(NoREinputneeded).3.AdjustC-201sothatth
10、elocaloscillatorfrequency shownbythe frequencycounter reads108.700MHz.TOLERANCE:108.700MHz+/2KHzB.FRONT-ENDALIGNMENTSAlignmentofthefront-end shouldonlybenecessaryafterrepairtothefront-endorcrystaloscillatorcircuits.a)TUNINGVOLTAGEItisessentialtochecktuning voltagebeforealigningtherestoffront-end.1.C
11、onnectDMMbetweenTP-105andground.2.Tune to88MHz,andadjustL-6ifthe voltageisincorrect.TOLERANCE:3.6V+/0.5V.3.Tuneto108MHzandconfirmthatthe voltageiswithinthefollowingspecification.SPECIFICATION:21-25V.b)TRACKING1.ConnectFMGenerator(150KHzsweep,100Voutput)to75ohmantennainputand Detector ProbetoPin1ofIC
12、102withgroundtothe tunershield.2.Settunerto106MHz,entorintoPreset8,andtunethegeneratorsothatcurveappearsonOscilloscope.3.AdjustC-2,C-9,C-liandC-14formaximumcurveheightonthe oscilloscopewhilereducingRFinputtokeepentirecurveondisplay.4.Settunerto90MHz,enterintoPreset1,andtune thegeneratorsothatcurveap
13、pearsontheoscilloscope.5.AdjustL-1, L-2,L-3andL-4formaximumcurveheight.6.Repeatabovesteps2, 3,4and5(usePreset1and8) tillbothfrequenciesareatmaximumcurveheight.SUGGESTED INSTRUMENTATIONHOOKUPoOSCILLOSCOPEFMGENERATORAUDIOOSC100IUSEONL?IFFMGENERATORWITHBUILT-INSWEEPUNAvAILABLEIWITHBUILT-INSWEEPlE: ST10
14、00ADISTORTION METERI1DISTORTIONOUTPUTSCHEMATICDIAGRAMOFDETECTORPROBECl02330p00o4.00Diodesshouldbepoint-contactFROMOUTgermanium;SomecommonlyTUNERCTOscocavailabletypesare:0A800A81AA1191N601N341N22PICTORIALDIAGRAMOFDETECTORPROBERiCENTERLEADTOPINICl02jjEEEESCOPEKeepleadsasshortaspossible,tominimizestray
15、signalpickup.ATFRONTEND56C.IFADJUSTMENT1.Settunerto98MHzapprox.(thetunermustbetunedtoanunoccupiedfrequency),andtuneFMGeneratortodisplayacurveonOscilloscope.2.AdjustL-5andL-101formaximumandsymmetricaloutputcurveonthe oscilloscopedisplay,using aslittleinput aspossible.D.DETECTORALIGNMENT1.Disconnect D
16、etector Probefromtunerand Oscilloscope,andconnecttuneroutputtothe oscilloscopeandDistortionAnalyzer.2.ConnectDMMacrossTP-101()andTP-102(+).3.Tune to98MHzandfeed1mVfromFMGenerator(Modulate1KHz100%)to75ohmantennainput.4.AdjustL-102SecondaryforlowestTHD.SPECIFICATION:lessthan0.12%(inMONO).5.AdjustL-102
17、PrimaryforOVreadingonDMM.TOLERANCE:+15OmV.6.Repeatabovesteps4& 5tillnofurtherimprovements.E.SIGNALMETERLEVEL1.Tuneto98MHzandfeed5VfromFMGeneratorto75ohmantennainput.2.AdjustR-127sothatthesecondLEDofsignalstrengthindicatorisjustlitup.ocCC)006.CheckandconfirmthatseparationunderwideIFbandwidthiswithint
18、hefollowingspecification.SPECIFICATION:morethan50dB.7.SwitchIFNARROWbutton(in),andmodulateLeft(orRight)channelonly.AdjustR-403forminimumoutputonRight(orLeft)channelVTVMandoscilloscope.Iftheleakoutputsonopposite channelsaredifferent,readjustR-403sothatreadingsbecomesameinbothleftandrightchannels.8.Ch
19、eckseparation undernarrowIFbandwidthand confirmitiswithinthefollowingspecification.SPECIFICATION:morethan40dB.H.FMNRCIRCUITConfirmthatFM NRbuttonisatOFFposition(in),atfirst.1.Tune to98MHzandfeed1mVwith100%modulationinto75ohmantennainputandsetreferenceforS/Nmeasurement.Withreferenceset,cancellthe ste
20、reomodulation andleavepilottoneonly.2.AdjusttheattenuatorofFMGeneratorsothatS/Nratioreads50dB.3.SwitchFMNRon,andadjustR-148sothatS/Nisimprovedby8dB.4.SwitchFMNRoff,andadjustattenuatorofFMGeneratorsothatS/Nratioreads60dB.5.SwitchFMNRon,andconfirmthatS/Nisimprovedbyapprox.2dB.F.STEREOSWITCHINGTHRESHOL
21、D1.ModulateFMGenerator1KHz100%Leftonly,pIus19KHzpilot8-10%.2.IncreaseFMGeneratorlevelupwardsfrom0andadjustR-126sothat stereolightturnsonandaudiooutputs,aswatchedonVTVMsand Oscilloscope,switchestoonechannelonlyat5Vinputlevel.TOLERANCE:+3V.Notethat,whenturninginputleveldown,theunitwillswitchintomonoat
22、alowerlevel,typically3.5pV.G.STEREODISTORTION AND SEPARATION(WIDE/NARROWIFBANDWIDTH)1.Tuneto98MHzandfeed1mVfromFMGeneratorto75ohmantennainput.2.ModulateLeft(or Right)channelonly,andadjustL-5andL-101slightly,sothatthedistortiononLeft(or Right)channelbecomesminimum.3.Checkdistortionatstereooperation u
23、nderwideIFband-width.SPECIFICATION:lessthan0.12%,stereoL+R.lessthan0.08%,stereoLonly.lessthan0.08%,stereoRonly.lessthan0.08%,stereoLR.4.Next,switchIFNARROWbutton(in)andcheckdistortionunderstereosignalinput.SPECIFICATION:lessthan0.8%,stereoLonly.lessthan08%stereoRonlylessthan0.8%,stereoL-R.5.ResetIFb
24、andwidthtowidepositionagainandmodulateLeftchannelonly.AdjustR-141forminimumoutputonRightchannelVTVMandoscilloscope.Next,modulateRightchannelonlyandadjustR-141forminimumoutputonLeftchannelVTVMandoscilloscope.Iftheleakoutputsonopposite channelsaredifferent,readjustR-141sothat readingsbecomesameinbothc
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