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1、NAD SERVICE MANUAL T 751 SURROUND SOUND RECEIVER T 751 SURROUND SOUND RECEIVER RadioFans.CN 收音机爱 好者资料库 2 SERVICE SAFETY PRECAUTIONS 1.Replacing the fuses CAUTION: FOR CONTINUED PROTECTION AGAINST THE RISK OF FIRE REPLACE ONLY WITH SAME TYPE OF FUSE. Reference NoPart NumberDescription M751*AH5120-020
2、0-0Fuse 5A 125V Time Lag 5x20 MM MITI/UL/CSA M754*AH5120-0052-0Fuse 1.6A 250V Time Lag 5x20 MM UL/CSA M752*C5120-0024-0Fuse 3.15A 250V Time Lag 5x20 MM SEMKO/VDE NOTE: : USA, CANADIAN MODEL ONLY. : EUROPEAN MODEL ONLY. 2.Safety check out (Only U.S.A. model) Before returning the product to the custom
3、er, make leakage current or resistance measurements to determine that exposed parts are acceptably insulated from 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. CONTENTS DESCRI
4、PTIONPAGE SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-4 REAR PANEL / FRONT PANEL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 DISASSEMBLY INSTRUCTIONS . . . . .
5、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6 WIRING DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-8 BLOCK DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6、. . . . . . . . . . . . . . . . . . . . . . . . . .9 ADJUSTMENT POINTS DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10 INSTRUMENT SETUP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
7、ALIGNMENT PROCEDURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11-12 IMPORTANT NOTES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12 PCB LAYOUT . . . . . . . . . . . . . . . . . . . .
8、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13-19 SCHEMATIC DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20-38 IC BLOCK DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9、. . . . . . . . . . . . . . . .39-46 ELECTRICAL PARTS LIST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .47-69 EXPLODED VIEW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .70 EXPLOD
10、ED VIEW PARTS LIST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .71-72 PACKING DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .73 RadioFans.CN 收音机爱 好者资料库 3 SPECIFICATIONS POWER AMPLIFIER
11、 AND PREAMPLIFIER SECTIONS Rated distortion(THD 20Hz-20 kHz FC/C/FR) 0.08% (THD 20Hz-20 kHz SL/SR) 0.3% Input Sensitivity(ref. 8 ohms, 1 kHz)180+/-30 mV S/N Ratio(A-wtd, 1KHz, 1W, 8 ohm) -76 dB (A-wtd, 1KHz, 70W, 8 ohm) -90 dB Frequency Response(20 Hz - 20 kHz)0 0.8 dB Channel Balance(1 dB to -40 dB
12、, 1 kHz) 2 dB (-41 dB to -50 dB, 1 kHz) 3 dB Audio muting at 1kHz 53 dB Headphone O/P in 0.1%, 600 ohm load, CD in 500mV, 1 kHz 10V Subwoofer out, 500mV in(THD at 2V O/P, 100 Hz) 0.5% (S/N at 2V O/P, 100 Hz) 80 dB Crosstalk(2V input, 10W, 1 kHz) -68 dB Continuous average power output 70 W Controls B
13、ass(at 500mV in, 1W out, 100 Hz) 9 dB Treble(at 500mV in, 1W out, 10 kHz) 9 dB SURROUND SECTION Channel separation I/p mode : L, R: 1V in, 1 kHz, Ch R, L 45 dB : o/p at unexpected, 1 kHz, Ch C 35 dB I/p mode : L= -R: 1V in, 1 kHz, Ch R, L 28 dB : o/p at unexpected, 1 kHz, Ch C 30 dB I/p mode : L= R:
14、 1V in, 1 kHz, Ch R, L 45 dB : o/p at unexpected, 1 kHz, Ch SL, SR 30 dB Frequency Response I/p mode : L, R: 1V in, 1W, Ch R, L40Hz0 1.5 dB 20kHz0 0.8 dB I/p mode : L= R: 1V in, 1W, Ch C300Hz0 0.8 dB 20kHz0 0.8 dB I/p mode : L= -R: 1V in, 1W, Ch SL, SR30Hz0 1.0 dB 6.5kHz-3 1.0 dB S/N Ratio ( 200mV i
15、n, 1, A-WTD w/ 1k termination) I/p mode : L, R: 1 kHz, Ch L, R 65 dB I/p mode : L=R: 1 kHz, Ch C 65 dB I/p mode : L=-R: 1 kHz, Ch SL, SR 65 dB THD (2.2V in, 1W, w/ 80 kHz LPF, 1 kHz) 0.2% AC-3/DTS SECTION Frequency Response FL, FR, C, SL, SR:200Hz0 0.8 dB 20kHz0 0.8 dB Distortion 1W all channels0.08
16、% S/N 1 W ( CCIR/ARM, 200 Hz NOTCH & 400 Hz HPF) 85 dB RadioFans.CN 收音机爱 好者资料库 4 AM TUNER SECTION Input level is expressed as the reading in open-circuit of 75-ohm source impedance signal generator Usable sensitivity (999/1000kHz) 30 dB S/N Ratio (5mV in) 38 dB THD (5mV in) 3% IF Rejection (450 kHz)
17、 36 dB Image Rejection (F+2xIF) 28 dB Selectivity 17 dB Output130+/- 20mV Loop sensitivity (20dB S/N) 999/1000 kHz 66 dB 603/600 kHz 66 dB 1404/1400 kHz 66 dB Frequency response (100 - 2.3 kHz, 5mV) 6 dB FM TUNER SECTION*C*AH Input level is expressed as the reading in open-circuit of 75-ohm source i
18、mpedance signal generator Usable Sensitivity ( 98 MHz) 15 dB 15 dB Signal / Noise RatioMono 72 dB 72 dB (60 dB, IHF wtd)Stereo 66 dB 66 dB Frequency Response (20 Hz - 15 kHz, 60 dB)0 1.5 dB0 1.5 dB Channel Separation (60 dB)100 Hz 30 dB 30dB 1 kHz 38 dB 38 dB 10 kHz 30 dB 30 dB Alternate Channel Sel
19、ectivity (40 dB, 400 kHz) 60 dB 45 dB Capture Ratio (40 dB) 3 dB 3 dB AM Suppression (60 dB, 100% Mod.FM, 30% Mod.AM) 48 dB 48 dB Image Rejection (119.4 MHz) 85 db 40 dB I.F. Rejection ( 10.7 MHz) 78 dB 65 dB Pilot Suppression (60 dB) 60 dB 60 dB THD (60 dB, L=R 75 kHz for AH, 40 kHz Dev for C) Mono
20、 0.25% 0.25% Stereo 0.35% 0.35% Auto-Search SensitivityOn 24 dB 24 dB Off 15 dB 15 dB RDS decode Sensitivity 26 dB 26 dB PHYSICAL SPECIFICATIONS Dimensions (Width x Height x Depth)435 x 131 x 348mm Net weight12.27kg (27 lbs) Shipping weight13.63kg (30 lbs) 5 2 1 78 34116125 1091413 REAR PANEL / FRON
21、T PANEL REAR PANEL FRONT PANEL 1. FM & AM ANTENNA 2. AM STEPPING FREQUENCY 3. TAPE 1 & CD INPUTS 4. 5.1 CHANNEL INPUTS 5. VIDEO 1 - VIDEO 4 (AUDIO & VIDEO) INPUTS 6. DIGITAL AUDIO INPUTS 7. AUDIO PRE-OUTS / SUBWOOFER OUT 8. MONITOR OUT 9. FRONT, CENTER & SURROUND SPEAKERS 10. SOFT CLIPPING 11. NAD-L
22、INK INPUT/OUTPUT 12. SWITCHED POWER OUTLETS (*AH ONLY) 13. AC POWER CORD 14. COOLING FAN 1. POWER 2. STAND-BY 3. DISPLAY 4. FM MUTE / MODE 5. MEMORY 6. PRESET / TUNE 7. DOWN / UPAND 8. VFL DISPLAY 9. VOLUME 10. HEADPHONE SOCKET & VIDEO 5 INPUT 11. AUDIO & VIDEO INPUT SELECTORS & SURROUND MODE 12. BA
23、SS & TREBLE CONTROLS 751 6 DISASSEMBLY INSTRUCTIONS 1. Remove machine screws M 4.0 x 6.0 ( 1 to 6 ) from the side panels. Remove tapping screw 3.0 x 8.5 ( 7 ) from the back panel. Refer to Figure No.1. Figure No.1 2. Pull both sides of the TOP COVER slightly outwards 8 and tilt approx. 35 and then r
24、emove in the direction as indicated by the arrow 9 . Refer to Figure No.2. Figure No.2. 7 6 5 4 1 3 2 9 8 8 SURROUND AMPLIFIER PCB AC OUTLET PCB (*AH ONLY) J708B M001 C834 TRIGGER PCB FRONT AMPLIFIER PCB AC3/DTS PCB VOLUME PCB POWER SWITCH PCB 87 WIRING DIAGRAM OSCRF 9 BLOCK DIAGRAM DIR CS-8414 DIG
25、SW 74HC153 DSP CS-4926 PSU & ISC MONITOR OUTPUT VIDEO INPUTS DIGITAL INPUTS OSD LC74763 2CH ADC CS-5331 TC-9273 ANALOG SWITCH TUNER SUBWOOFER LA1837 LC7218 LC72723 VIDEO SWITCH BA7625 (4cs) DAC CS4340 3pcs, 6ch tot 6CH VOLUME M62447SP 5CH POWER AMPLIFIER MCU LC87F65C8A VFL DISPLAY NAD LINK IN/OUT RE
26、MOTE SENSOR KEY MATRIX MUTING 5.1CH INPUT EEPROM VIDEO OUTPUTS AUDIO INPUTS AUDIO OUTPUTS 10 ADJUSTMENT POINTS DIAGRAM 1. TUNER 2. IDLE CURRENT - Front Amplifier & Surround Amplifier Board 11 ALIGNMENT PROCEDURES AMPLIFIER SECTION Idle Current StepItemConnectionAdjustment Adjust for 1Front Left Chan
27、nelVoltmeter to P502 on Front Amp BoardR5742mV0.2mV 2Front Right ChannelVoltmeter to P501 on Front Amp BoardR5732mV0.2mV 3Center ChannelVoltmeter to P503 on Front Amp BoardR5992mV0.2mV 4Rear Left ChannelVoltmeter to JP801 on Surround Amplifier BoardR8672mV0.2mV (PCB N0901C-AMP2) 5Rear Right ChannelV
28、oltmeter to JP802 on Surround Amplifier BoardR8682mV0.2mV (PCB N091C-AMP2) INSTRUMENT SETUP 1. FM MEASUREMENT Fig. 1 Fig. 2 2. RDS MEASUREMENT Fig. 3 3. AM MEASUREMENT Fig. 4 FM SIGNAL GENERATOR ANTENNA TERMINAL OUTPUT TERMINAL DISTORTION ANALYZER DISTORTION ANALYZER AC VOLTMETER OSCILLOSCOPE AC VOL
29、TMETER OR OSCILLOSCOPE AC VOLTMETER OR OSCILLOSCOPE OUTPUT TERMINAL OUTPUT TERMINAL L R ANTENNA TERMINAL ANTENNA TERMINAL ANTENNA TERMINAL AM LOOP ANTENNA (Accessory) AM LOOP ANTENNA 60cm DIGITAL MILLIVOLT METER VT-J914 FM SIGNAL GENERATOR AM SIGNAL GENERATOR FM SIGNAL GENERATOR RDS GENERATOR FM STE
30、REO GENERATOR P-901 DC MILLIVOLT METER UNIT UNIT UNIT UNIT 12 IMPORTANT NOTES 1. Show the software version Press “VIDEO 5” and “EXT 5.1” and “DISPLAY”. 2. Toggle between PAL and NTSC Press “MEMORY” and “VIDEO 1”. 3. Light UP all the icon on the VFL. Press “VIDEO 1” and “EXT 5.1” and “DISPLAY”. 4. De
31、lete All Tuner Presets a) Change the setting of 9kHz/10kHz AM step switch and then switch on the unit. b) Switch off the unit and put back the 9kHz/10kHz AM step switch to the right setting. Then switch on the unit. (i.e. 9kHz=C ver., 10kHz=AH ver.) FM/RDS SECTION - FM mono:1kHz, 75kHz devi., 60dB/V
32、 - FM stereo:1kHz, 67.5kHz devi., 60dB/V Pilot signal 19kHz 7.5kHz devi. OUTPUTS - Connect the non-inductive type resistor of 8 ohms to the all speaker terminals unless otherwise noted. Item FM IF/RF Stereo Distortion Stereo Separation Muting Level Signal output Step 1DC voltmeterL9410100mV 3 Distor
33、tion analyzer Distortion analyzer Oscilloscope Oscilloscope L942 R956 R941 Minimum Minimum 2AC voltmeter IFT on the front end IFT on the front end Maximum Maximum separation Connection of instrument Fig.1 Fig.2 Fig.2 Fig.1 Channel L or R 1kHz 99.0MHz 1kHz 75kHz devi. 65dBf (60dB) 99.0MHz Ext. mod. 6
34、5dBf (60dB) FM SG output Stereo mod- ulator output Tuning frequency 99.0MHz 99.0MHz Channel L or R 1kHz 99.0MHz Ext. mod. 65dBf (60dB) 99.0MHz Ext. mod.65dBf(60dB) RDS 2% MOD 99.0MHz 18dB 99.0MHz 99.0MHz RDS Fig.399.0MHz Output indicator Adjustment point Adjust for Remarks FM MUTE/MODE switch: ON/AU
35、TO Repeat the steps 1 to 3 until no fur- ther adjustment is necessary. FM MUTE/MODE switch: ON/AUTO Dont turn more than +/-180 Repeat stereo distortion and stereo separation alignment until THD at minimum and separation at maximum. Decode the RDS- Program Station. AM SECTION AM Modulation:400Hz, 30%
36、 For AH Version Step 1 2 3 530kHz 600kHz 990kHz 600kHz 400Hz 30% mod. 60dB/m AM SG output Tuning frequency Output indicator Adjustment point 600kHz 400Hz 30% mod. 60dB/m AC voltmeter AC voltmeter Digital DC voltmeter L972 OSC coil on RF block L971 RF coil on RF block L971 Adjust for 1.350.2V Maximum
37、 Maximum Step 1 2 3 522kHz or 531kHz 603kHz 999kHz 600kHz 400Hz 30% mod. 60dB/m AM SG output Tuning frequency Output indicator Adjustment point 600kHz 400Hz 30% mod. 60dB/m AC voltmeter AC voltmeter Digital DC voltmeter L972 OSC coil on RF block L971 RF coil on RF block L971 Adjust for 1.30.2V (522k
38、Hz) 1.350.2V (531kHz) Maximum Maximum For C Version 13 PCB LAYOUT SPEAKER BOARD DIGITAL BOARD PRIMARY BOARD SECONDARY BOARD TONE BOARD 14 PSU BOARD S-VIDEO BOARD LED BOARDAC OUTLET BOARD 15 AC3 / DTS BOARD - COMPONENT SIDE AC3 / DTS BOARD - SOLDER SIDE 16 MULTI-CHANNEL BOARD MAIN BOARD 17 KEYBOARD -
39、 COMPONENT SIDEKEYBOARD - SOLDER SIDE 18 TRIGGER BOARDLOAD BOARD FRONT AMPLIFIER BOARD VIDEO 5 BOARD VOLUME BOARDPOWER SWITCH BOARD 19 SURROUND AMPLIFIER BOARD TUNER BOARD VIDEO BOARDAUDIO BOARD 20 SCHEMATIC DIAGRAM (TO KEY J204A) (TO FRONT AMP J504A) (TO SEC J702A) LOAD NOTE: 1. RESISTORS ARE CARBO
40、N FILM 5% 1/8W UNLESS OTHERWISE SPECIFIED. 2. CERAMIC CAPACITORS ARE 50V +80/-20%. UNLESS OTHERWISE SPECIFIED. 2221 VOLUME PCB LED PCB KEY NOTE: 1. RESISTORS ARE CARBON FILM 5% 1/8W UNLESS OTHERWISE SPECIFIED. 2. CERAMIC CAPACITORS ARE 50V +80/-20%. UNLESS OTHERWISE SPECIFIED. 2324 AC3 / DTS NOTE: 1
41、. RESISTORS ARE CARBON FILM 5% 1/8W UNLESS OTHERWISE SPECIFIED. 2. CERAMIC CAPACITORS ARE 50V 10%. UNLESS OTHERWISE SPECIFIED. 2625 (TO AC3 J604B) (TO FRONT AMP J502A) (TO VIDEO J708B) MAIN BOARD NOTE: 1. RESISTORS ARE CARBON FILM 5% 1/10W UNLESS OTHERWISE SPECIFIED. MF - METAL FILM 2. CERAMIC CAPAC
42、ITORS ARE 50V 10%. UNLESS OTHERWISE SPECIFIED. 2728 MULTI-CHANNEL NOTE: 1. RESISTORS ARE CARBON FILM 5% 1/8W UNLESS OTHERWISE SPECIFIED. 2. CERAMIC CAPACITORS ARE 50V 10%. UNLESS OTHERWISE SPECIFIED. 3029 (MF) (CC) (CC) (CC) (CC) (CC) (CC) (CC) (CC) (CC) (CC) (CC) (CC) (CC) (CC) (CC) (MF) (MF) (MF)
43、(MF) (MF) (MF) (MF) (MF) (MF) (MF) (MF) (MF) (MF) (MF) (MF) (MF) (MF) (MF) (MF) FRONT AMPLIFIER NOTE: 1. RESISTORS ARE CARBON FILM 5% 1/8W UNLESS OTHERWISE SPECIFIED. CC - CERAMIC CASE MF - METAL FILM 2. COMPONENTS MARKED “” ARE SAFETY CRITICAL PARTS. 3132 (TO FRONT AMP J802B) C003 0.022u C001 47u/5
44、0V M002 M001C834 R002 10R 1/2W Vin 1 GND 2 Vout 3 U001 7812 R001 4K7 C002 10u/16V (MF) (MF) (CC) (CC) (CC) (CC) (CC) (CC) (CC) (CC) (CC) (CC) (MF) (MF) (MF) (MF) (MF) (MF) (MF)(MF) (MF)(MF) (MF)(MF) SURROUND AMPLIFIER NOTE: 1. RESISTORS ARE CARBON FILM 5% 1/8W UNLESS OTHERWISE SPECIFIED. CC - CERAMI
45、C CASE MF - METAL FILM 2. CERAMIC CAPACITORS ARE 50V 10%. UNLESS OTHERWISE SPECIFIED. 3. COMPONENTS MARKED “” ARE SAFETY CRITICAL PARTS. 3433 TUNER NOTE: 1. RESISTORS ARE CARBON FILM 5% 1/8W UNLESS OTHERWISE SPECIFIED. 2. CERAMIC CAPACITORS ARE 50V 10%. UNLESS OTHERWISE SPECIFIED. 3536 S-VIDEO NOTE:
46、 1. RESISTORS ARE CARBON FILM 5% 1/8W UNLESS OTHERWISE SPECIFIED. 2. CERAMIC CAPACITORS ARE 50V 10%. UNLESS OTHERWISE SPECIFIED. 37 AUDIO NOTE: 1. RESISTORS ARE CARBON FILM 5% 1/8W UNLESS OTHERWISE SPECIFIED. 2. CERAMIC CAPACITORS ARE 50V 10%. UNLESS OTHERWISE SPECIFIED. 38 SECONDARY (TO FRONT AMP J
47、501A) (AH ONLY) (F) POWER SUPPLY UNIT NOTE: 1. RESISTORS ARE CARBON FILM 5% 1W UNLESS OTHERWISE SPECIFIED. F - FUSIBLE 2. CERAMIC CAPACITORS ARE 50V 10%. UNLESS OTHERWISE SPECIFIED. 3. COMPONENTS MARKED “” ARE SAFETY CRITICAL PARTS. 39 IC BLOCK DIAGRAM AC3 BOARD U101: 74HC153 AC3 BOARD U102: 74HC157
48、 AC3 BOARD U103: CS5331A 14 7 9 A 2 1 6 5 4 3 15 B 1G 1C0 TG TG TG TG TG TG TG TG TG TG TG TG 1C1 1C2 1Y 2Y 1C3 10 11 12 13 2C0 2C1 2C2 2C3 2G 11GVCC16 2B2G15 31C3A14 41C22C313 51C12C212 61C02C111 71Y2C010 8GND2Y9 4 1Y 7 2Y 9 3Y 12 4Y 15 1 G 13 4B 10 3B 6 2B 5 2A 3 1B 2 1A 11 3A 14 4A A/B 1A/BVCC16
49、21AG15 31B4A14 41Y4B13 52A4Y12 62B3A11 72Y3B10 8GND3Y9 AINL 8 + - + - + - 5 6 7 423 1 AINR AGND S/H Comparator MCLKSCLKLRCK SDATA Comparator Voltage ReferenceSerial Output Interface Digital Decimation Filter Digital Decimation Filter High Pass Filter High Pass Filter S/H VA+ + - LP Filter DAC DAC LP Filter 40 AC3 BOARD U104, U109, U116, U131, U134: NJM5532 AMPLIFIER 1 OUTPUT INVERTING INPUT NON-INVERTING INPUT V AMPLIFIER 2 V + OUTPUT INVERTING INPUT NON-INVERTING INPUT 1 2 3 4 8 7 6 5 + + 27 368-11,14-17185419762021 37 38 44 43 42 41 40 39 3
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