NAD-C420-tun-sm 维修电路原理图.pdf
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1、NADSERVICE MANUALC 420STEREOAM/FM TUNERC 420STEREOAM/FM TUNERRadioFans.CN 收音机爱 好者资料库2SERVICE SAFETY PRECAUTIONS1.Safety check out(Only U.S.A. model)Before returning the product to the customer, make leakage current or resistance measurementsto determine that exposed parts are acceptably insulated fr
2、om the supply circuit.Parts marked with the symbol are critical with regard to the risk of fire and electric shock.Replace only with parts recommended by the manufacturer.CONTENTSDESCRIPTIONPAGESPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3、 . . . . . . . . . . . . .3REAR PANEL / FRONT PANEL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4DISASSEMBLY INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5BLOCK DIAGRAM . . . . . . . .
4、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6WIRING DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7ADJUSTMENT POINTS DIAGRAM . . . . . . . . . . . . . . . . . . . .
5、. . . . . . . . . . . . . . . . . . . . . . . . . .8INSTRUMENT SETUP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9ALIGNMENT PROCEDURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6、.10PCB LAYOUT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-12SCHEMATIC DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13-16IC BLOCK DIAGRAM . . . . . . . . . . . .
7、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17-19ELECTRICAL PARTS LIST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20-25EXPLODED VIEW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8、 . . . . . . . . . . . . . . . . . . . .26EXPLODED VIEW PARTS LIST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27PACKING DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28RadioFa
9、ns.CN 收音机爱 好者资料库3SPECIFICATIONSAM TUNER SECTIONInput level is expressed as the reading in open-circuitof 75-ohm source impedance signal generatorUsable Sensitivity (999/1000kHz)30dBS/N Ratio (5mV in)38dBTHD (5mV in)3%IF Rejection (450kHz)36dBImage Rejection (F+2xIF)28dBSelectivity17dBOutput130 +/-20
10、mVLoop Sensitivity (20dB S/N)999/1000 kHz66 dB603/600 kHz66 dB1404/1400 kHz66 dBFrequency response (100 - 2.3 kHz, 5mV)6 dBFM TUNER SECTION*C*AHInput level is expressed as the reading in open-circuitof 75-ohm source impedance signal generatorUsable Sensitivity (98 MHz)13 dB13 dBSignal / Noise RatioM
11、ono72 dB72 dB(60 dB, IHF wtd)Stereo66 dB66 dBFrequency Response (20 Hz - 15 kHz, 60 dB)01.0 dB01.0 dBChannel Separation (60 dB)30 Hz33 dB33 dB1 kHz42 dB42 dB10 kHz32 dB32 dBAlternate Channel Sensitivity(40 dB, 400 kHz)60 dB45 dBCapture Ratio (40 dB)3 dB3 dBAM Suppression(60 dB, 100% Mod.FM, 30% Mod
12、AM)65 dB65 dBImage Rejection (119.4 MHz)85 dB85 dBI.F. Rejection (10.7 MHz)78 dB78 dBPilot Suppression (60 dB)60 dB60 dBTHD (60 dB, L=R 75 kHz for AH, 40 kHz Dev for C)Mono0.25%0.25%Stereo0.35%0.35%Auto-Search sensitivityOn24 dB24 dBOff15 dB15 dBRDS Decode Sensitivity26 dB26 dBPHYSICAL SPECIFICATION
13、SDimensions (Width x Height x Depth)435 x 80 x 285 mmNet weight4 kg (8.8 lbs)Shipping weight5.1 kg (11.22 lbs)4REAR PANEL / FRONT PANELREAR PANELFRONT PANEL1. FM ANTENNA2. AM ANTENNA3. OUTPUT4. NAD-LINK IN/OUT5. 12V TRIGGER IN6. AC LINE CORD1. POWER ON / OFF2. STAND-BY LED3. BLEND4. MEMORY5. FM MUTE
14、 / MODE6. AM / FM7. DISPLAY8. PRESET / TUNE9. DISPLAY AREA10. PRESET / TUNE AND IMPORTANT NOTES1. Show the software versionPress “PRESET/TUNE” and “TUNE UP” ().2. Light UP all the icon on the VFLPress “PRESET/TUNE” and “TUNE DOWN” ().3. CPU ResetsPress “PRESET/TUNE” and “TUNE DOWN” () and any one ke
15、y.4. AM Step 10K/9K ChangeAdd D206: 10KHz / Delete D206: 9KHz.54312766DISASSEMBLY INSTRUCTIONS1. Remove machine screws M 4.0 x 6.0 ( 1 to 4 ) from the side panels.Remove tapping screw 3.0 x 8.5 5 from the back panel.Refer to Figure No.1.Figure No.12. Pull both sides of the TOP COVER slightly outward
16、s 6 and tilt approx. 35 and then removein the direction as indicated by the arrow 7 . Refer to Figure No.2.Figure No.2.56BLOCK DIAGRAMAM LOOP ANTFM ANTOUTPUTFRONT ENDENV172D3G1VFDCPULC866448BU201KEY MATRIXTrigger INU202EEPROM24C08PLLLC72723MRDS DECODERU901AM/FM IFLA1837MUTINGDIODEMATRIXNAD LINKIN-OU
17、TM218REMOTESENSORPOWERSUPPLYVFD-VP+5V CPU+10VAC INPUTLRVTVTcedataclkRDS-CLKRDS-SIGRDS-DATAMPXINdataout(#1)=Power On(#2)=Protect (Flash 2Hz)(#1)+(#2)=Standby(#1)(#2)LC7218U903ST/MO, MUTE, SMETERTUNEFMOSC/IFAMOSC/IF127171623230U902212345152319586 IN2 OUT24161479161422787172575767419187WIRING DIAGRAMMA
18、IN BOARDKEY BOARDLED BOARDTRANSFORMERYELLOWBLUEWHITEPOWER SUPPLY BOARDTrigger InAudioL,R Out8ADJUSTMENT POINTS DIAGRAMOSCRFVTTrigger InAudioL,R OutFMSIGNALGENERATORANTENNATERMINALOUTPUTTERMINALDISTORTIONMETERDISTORTIONMETERACVOLTMETEROSCILLOSCOPEACVOLTMETEROROSCILLOSCOPEACVOLTMETEROROSCILLOSCOPEOUTP
19、UTTERMINALOUTPUTTERMINALLRANTENNATERMINALANTENNATERMINALANTENNATERMINALAM LOOPANTENNA(Accessory)AM LOOPANTENNA60cmDIGITALMILLIVOLT-METERVT_J911FMSIGNALGENERATORAMSIGNALGENERATORFMSIGNALGENERATORRDSGENERATORFMSTEREOGENERATORP901OUTPUTTERMINALDCMILLIVOLT-METERUNITUNITUNITUNIT9INSTRUMENT SETUP1. FM MEA
20、SUREMENTFig. 1Fig. 22. RDS MEASUREMENTFig. 33. AM MEASUREMENTFig. 410ALIGNMENT PROCEDURESFM/RDS SECTION- FM mono:1kHz, 75kHz devi., 60dB/V- FM stereo:1kHz, 67.5kHz devi., 60dB/VPilot signal 19kHz 7.5kHz devi.OUTPUTS- Connect the 47Kohm resistor unless otherwise noted.ItemFMIF/RFStereoDistortionStere
21、oSeparationMuteLevelSignaloutputStep1DC voltmeterL941070mV3DistortionanalyzerDistortionanalyzerOscilloscopeOscilloscopeL942R941R956MinimumMinimum2AC voltmeterIFT on thefront endIFT on thefront endMaximumMaximumseparationDistortionMeterMinimumConnectionof instrumentFig.1Fig.2Fig.2Fig.1Channel Lor R 1
22、kHz99.0MHz1kHz 75kHz devi.65dBf (60dB)99.0MHz Ext.mod. 65dBf(60dB)FM SGoutputStereo mod-ulator outputTuningfrequency99.0MHz99.0MHzChannel Lor R 1kHz99.0MHz Ext.mod. 65dBf(60dB)99.0MHz Ext.mod. 65dBf(60dB)RDS 2% MOD99.0MHz 18dB99.0MHz99.0MHzRDSFig.399.0MHzOutputindicatorAdjustmentpointAdjustforRemark
23、sFM MUTE/MODEswitch: ON/AUTORepeat the steps1 to 3 until no fur-ther adjustment isnecessary.FM MUTE/MODEswitch: ON/AUTODont turn morethan 180Repeat stereodistortion andstereo separationalignment untilTHD at minimumand separation atmaximum.Decodethe RDS-Program stationAM SECTIONAF Modulation: 400Hz,
24、30%For AH VersionStep123530kHz600kHz990kHz600kHz400Hz 30% mod.60dB/mAM SGoutputTuningfrequencyOutputindicatorAdjustmentpoint600kHz400Hz 30% mod.60dB/mACvoltmeterACvoltmeterDigitalDCvoltmeterL972OSC coilon RFblock M971RF coilon RFblock M971Adjustfor1.350.2VMaximumMaximumStep123522kHzor531kHz603kHz999
25、kHz600kHz400Hz 30% mod.60dB/mAM SGoutputTuningfrequencyOutputindicatorAdjustmentpoint600kHz400Hz 30% mod.60dB/mACvoltmeterACvoltmeterDigitalDCvoltmeterL972OSC coilon RFblock M971RF coilon RFblock M971Adjustfor1.30.2V (522kHz)1.350.2V (531kHz)MaximumMaximumFor C Version11PCB LAYOUTPOWER SUPPLY BOARDK
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