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NAD T 751 Service Manual

Summary of T 751

  • Page 1

    Nad ser vice manual t 751 s u r r o u n d sound receiver t 751 surround sound receiver.

  • Page 2: Service Safety Precautions

    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 no part number description m751*ah 5120-0200-0 fuse 5a 125v time lag 5x20 mm miti/ul/csa m754*ah 5120-0052-0 fuse 1.6a 250v time lag 5x20 mm u...

  • Page 3: Specifications

    3 specifications power amplifier 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 - 2...

  • Page 4

    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 dbµ s/n ratio (5mv in) ≥ 38 db thd (5mv in) ≤ 3% if rejection (450 khz) ≥ 36 db image rejection (f+2xif) ≥ 28 db selectivity ≥ 17 db output 130...

  • Page 5: Rear Panel / Front Panel

    5 2 1 7 8 3 4 11 6 12 5 10 9 14 13 rear panel / front 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, ce...

  • Page 6: Disassembly Instructions

    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 remove in the direction a...

  • Page 7

    Surround amplifier pcb ac outlet pcb (*ah only) j708b m001 c834 trigger pcb front amplifier pcb ac3/dts pcb volume pcb power switch pcb 8 7 wiring diagram.

  • Page 8

    Osc rf 9 block diagram dir cs-8414 dig sw 74hc153 dsp cs-4926 psu & isc monit or output video inputs digit al 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 ...

  • Page 9: Alignment Procedures

    11 alignment procedures amplifier section idle current step item connection adjustment adjust for 1 front left channel voltmeter to p502 on front amp board r574 2mv±0.2mv 2 front right channel voltmeter to p501 on front amp board r573 2mv±0.2mv 3 center channel voltmeter to p503 on front amp board r...

  • Page 10: Important Notes

    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. Delete all tuner presets a) change the setting of 9khz/10khz ...

  • Page 11: Pcb Layout

    13 pcb layout speaker board digital board primary board secondary board tone board.

  • Page 12

    14 psu board s-video board led board ac outlet board.

  • Page 13

    15 ac3 / dts board - component side ac3 / dts board - solder side.

  • Page 14

    16 multi-channel board main board.

  • Page 15

    17 keyboard - component side keyboard - solder side.

  • Page 16

    18 trigger board load board front amplifier board video 5 board volume board power switch board.

  • Page 17

    19 surround amplifier board tuner board video board audio board.

  • Page 18: Schematic Diagram

    20 schematic diagram (t o key j204a) (t o fr ont amp j504a) (t o sec j702a) load note: 1. Resist ors are carbon film 5% 1/8w unless other wise specified. 2. Ceramic cap acit ors are 50v +80/-20%. Unless other wise specified..

  • Page 19

    22 21 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..

  • Page 20

    23 24 ac3 / dts note: 1. Resistors are carbon film 5% 1/8w unless otherwise specified. 2. Ceramic capacitors are 50v 10%. Unless otherwise specified..

  • Page 21

    26 25 (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 capacitors are 50v 10%. Unless otherwise specified..

  • Page 22

    27 28 multi-channel note: 1. Resistors are carbon film 5% 1/8w unless otherwise specified. 2. Ceramic capacitors are 50v 10%. Unless otherwise specified..

  • Page 23

    30 29 (mf) (cc) (cc) (cc) (cc) (cc) (cc) (cc) (cc) (cc) (cc) (cc) (cc) (cc) (cc) (cc) (mf) (mf) (mf) (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 fil...

  • Page 24

    31 32 (to front amp j802b) c003 0.022u c001 47u/50v m002 m001 c834 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...

  • Page 25

    34 33 tuner note: 1. Resistors are carbon film 5% 1/8w unless otherwise specified. 2. Ceramic capacitors are 50v 10%. Unless otherwise specified..

  • Page 26

    35 36 s-video note: 1. Resistors are carbon film 5% 1/8w unless otherwise specified. 2. Ceramic capacitors are 50v 10%. Unless otherwise specified..

  • Page 27

    37 audio note: 1. Resist ors are carbon film 5% 1/8w unless other wise specified. 2. Ceramic cap acit ors are 50v 10%. Unless other wise specified..

  • Page 28

    38 second ar y (t o fr ont amp j501a) (ah onl y) (f) power supply unit note: 1. Resist ors are carbon film 5% 1w unless other wise specified. F - fusible 2. Ceramic cap acit ors are 50v 10%. Unless other wise specified. 3. Components marked “ ” are safety critical p a r ts..

  • Page 29: Ic Block Diagram

    39 ic block diagram ac3 board u101: 74hc153 ac3 board u102: 74hc157 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 1 1g vcc 16 2 b 2g 15 3 1c3 a 14 4 1c2 2c3 13 5 1c1 2c2 12 6 1c0 2c1 11 7 1y 2c0 10 8 gnd ...

  • Page 30

    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 36 8-11,14-17 18 5 4 19 7 6 20 21 37 38 44 43 42 41 40 39 3 28 29 25 26 22 30 31 32 33 34 35 2 13 24 1 1...

  • Page 31

    41 rxp rs422 receiver clock & data recovery de-mux audio serial port registers mux mux vd+ dgnd va+ va+ filt agnd mck m3 m3 m2 m1 m0 sdata sck fsync c u verf cs12/fck sel c0/e0 ca/e1 cb/e2 cc/f0 cd/f1 ce/f2 ref cbl rxn 9 10 13 16 6 5 4 3 2 27 25 15 28 14 1 11 12 26 23 24 18 17 19 21 20 22 8 7 ac3 bo...

  • Page 32

    42 ac3 board u118-u119: 74hc00 ac3 board u114: 74hcu04 audio board u301: tc9273n-004 audio board u302: 4066 digital board u761: 74hct00 load board u701: njm4558d 1 1a 14 vac 2 1y 13 6a 3 2a 12 6y 4 2y 11 5a 5 3a 10 5y 6 3y 9 4a 7 gnd 8 4y a1 b1 y1 a2 b2 y2 gnd vcc b4 a4 y4 b3 a3 y3 1 2 3 4 5 6 7 14 ...

  • Page 33

    43 multi-channel board u605-u611: njm5532 main board u723: njm78m56fa s-video & video board u402-u404: ba7625 multi-channel board u602: tc9164an 42 dvdd 1 out4 41 clk 2 out3 40 da ta 3 out2 39 la tch 4 out1 38 dgnd 5 a vdd 37 agnd 6 swin 36 sw out 7 gnds 35 srout 8 srin 34 slout 9 slin 33 cout 10 gn...

  • Page 34

    44 s-video board u401: lc74763-9012 key board u201: lc87f65c8a 8 cs 9 sin 10 sclk 15 rst 11 secam 12 525/625 13 ntsc/pal 14 3.58/4.42 serial parallel converter composite synchron- ization singal control afc circuit sync separator 8-bit latch and command decoder horizontal character size register hor...

  • Page 35

    45 key board u202: eeprom 24c02 tuner board u901: la1837 dout ack word address buffers start/stop logic control logic state counters slave address comparators a0 a1 a2 scl wp sda vss vcc xdec data in storage high voltage/ timing control e 2 prom column decoders sense amps shift registers vcc a0 8 1 ...

  • Page 36

    46 tuner board u902: lc72723m tuner board u903: lc7218 vdda 3 reference voltage antialiasing filter data decoder vref 1 vref flout 5 cin 6 pll (57khz) clock recovery (1187.5hz) + _ vddd 11 vssd 10 rdda 14 rdcl 15 mode 12 rst 13 rds-id/ready 16 vssa 4 mpxin 2 test 7 test 57khz bpf (scf) smoothing fil...

  • Page 37: Electrical Parts List

    47 electrical parts list reference no. Part no. Description ac3 board assembly pc board 2701 pcb-n0910c-ac3 pcb assy ac3 n091xc capacitors c101 150f-104k-j-bd cc 50v 0.1µf 10% 0805 1.2x2.0 c102 150e-104m-j-bd cc 25v 0.1µf20% 0805 1.2x2.0 c103 150f-104k-j-bd cc 50v 0.1µf 10% 0805 1.2x2.0 c104 157c-10...

  • Page 38

    C176 157c-107m-5-iu ce 10v 100µf 20% rl 5x11 c179-c180, c183-c184 150f-104k-j-bd cc 50v 0.1µf 10% 0805 1.2x2.0 c193-c194, c198 150f-104k-j-bd cc 50v 0.1µf 10% 0805 1.2x2.0 c199 157d-106m-5-gm ce 16v 10µf 20% rl 4x7 c1101 157d-475m-5-ei ce 16v 4.7µf 20% rl 3x5 c1102 15ff-224z-j-bd cc 50v 0.22µf +80/-...

  • Page 39

    49 r130 4720-151j-j rmg 1/10w 150r 5% 0805 r131 4720-103j-j rmg 1/10w 10k 5% 0805 r133 4720-151j-j rmg 1/10w 150r 5% 0805 r134 4720-103j-j rmg 1/10w 10k 5% 0805 r135-r136 4720-102j-j rmg 1/10w 1k 5% 0805 r137 4720-151j-j rmg 1/10w 150r 5% 0805 r138 4720-103j-j rmg 1/10w 10k 5% 0805 r139 4720-102j-j ...

  • Page 40

    50 c503-c504 150f-101j-5-if cc 50v 100pf 5% rl 5x3.5 c505-c506 157d-227m-5-kw ce 16v 220µf 20% rl 6x12 c507-c510 157f-106m-5-iu ce 50v 10µf 20% rl 5x11 c511-c512 150f-070d-5-gg cc 50v 7pf 0.5pf rl 4x4 c513-c514 150f-101j-5-if cc 50v 100pf 5% rl 5x3.5 c515-c516 150f-181k-5-gg cc 50v 180pf 10% rl 4x4 ...

  • Page 41

    51 transistors q501-q506 4860-0190-5 tr 2sc1845 (f.E) rl q507-q510 485a-949o-5 tr 2sa949-o hfe 70-140 toshiba q511-q512 485c-2229-5 tr 2sc2229-0 hfe 70-140 toshiba q513-q514 485a-949o-5 tr 2sa949-o hfe 70-140 toshiba q515-q516 485c-2229-5 tr 2sc2229-0 hfe 70-140 toshiba q517-q518 4860-1220-5 tr 2sc3...

  • Page 42

    52 r567, r569 4717-2r2j-2 rmf 1/2w 2.2r 5% at r570 4701-225j-c rcf 1/8w 2.2m 5% ats r571 4705-333j-2 rcf 1/4w 33k 5% at r572 4701-103j-2 rcf 1/8w 10k 5% at r575 4701-473j-2 rcf 1/8w 47k 5% at r577-r578 4718-r22j-2 rmf 1w 0.22r 5% at r580 4701-562j-c rcf 1/8w 5.6k 5% ats r581 4701-273j-c rcf 1/8w 27k...

  • Page 43

    53 c803-c804 150f-101j-5-if cc 50v 100pf 5% rl 5x3.5 c805-c806 150f-020c-5-gg cc 50v 2pf 0.25pf rl 4x4 c807-c808 150f-471k-5-gg cc 50v 470pf 10% rl 4x4 c809-c810 157d-227m-5-kw ce 16v 220µf 20% rl 6x12 c811-c812 157d-476m-5-iu ce 16v 47µf 20% rl 5x11 c813-c814 150f-181k-5-gg cc 50v 180pf 10% rl 4x4 ...

  • Page 44

    54 r835-r836 4701-332j-c rcf 1/8w 3.3k 5% ats r837-r838 4715-331a-2 rmf 1/4w 330r 1% at r839-r840 4701-471j-c rcf 1/8w 470r 5% ats r841-r844 4717-2r2j-2 rmf 1/2w 2.2r 5% at r845-r846 4701-271j-c rcf 1/8w 270r 5% ats r847-r848 4701-104j-c rcf 1/8w 100k 5% ats r849-r850 4717-560j-2 rmf 1/2w 56r 5% at ...

  • Page 45

    55 r342 4701-105j-c rcf 1/8w 1m 5% ats r343 4701-222j-c rcf 1/8w 2.2k 5% ats r344 4701-105j-c rcf 1/8w 1m 5% ats r345 4701-222j-c rcf 1/8w 2.2k 5% ats r346 4701-105j-c rcf 1/8w 1m 5% ats r347 4701-222j-c rcf 1/8w 2.2k 5% ats r348 4701-105j-c rcf 1/8w 1m 5% ats r349 4701-222j-c rcf 1/8w 2.2k 5% ats r...

  • Page 46

    56 c202 150f-103k-2-fc cc 50v 0.01µf 10% at 3.5 x2 c203-c204 150f-220k-5-gg cc 50v 22pf 10% rl 4x4 c205 150f-104z-5-iu cc 50v 0.1µf +80/-20% rl 5x11 c206 157b-107m-5-km ce 6.3v 100µf 20% rl 6x7 c207 150f-104z-5-iu cc 50v 0.1µf +80/-20% rl 5x11 c208 157d-476m-5-iu ce 16v 47µf 20% rl 5x11 diodes d201-...

  • Page 47

    57 r262 4701-223j-c rcf 1/8w 22k 5% ats r263-r274 4701-104j-c rcf 1/8w 100k 5% ats r280 4701-102j-c rcf 1/8w 1k 5% ats r282 4701-103j-c rcf 1/8w 10k 5% ats ics u201 3131-3810-1 ic lc87f65c8a 8 bit mcu masked u202 3131-3920-0 ic eeprom 24c02 2kbit 8pin dip led board assembly pc board 2201 pcb-n0910c-...

  • Page 48

    58 ic u701 3130-0890-0 ic njm4558d dual op amp. Main board assembly pc board 2301 pcb-n0910c-main pcb assy main n091xc capacitors c717 157e-338m-5-5$ ce 25v 3300µf 20% rl 16x32 c718 157e-108m-5-x& ce 25v 1000µf 20% rl 12.5x25 c720, c721 150f-223k-2-fd cc 50v 0.022µf 10% at 3.2x2.2 c722-c723 157f-106...

  • Page 49

    59 jacks 1102 2113-1808-0 4p rca jack r/w gold w/shield 1103 2113-1809-0 2p rca jack bk/bk gold w/shield 1105 2113-1808-0 4p rca jack r/w gold w/shield 1106 2113-1809-0 2p rca jack bk/bk gold w/shield capacitors c601-c606 150f-101k-2-fc cc 50v 100pf 10% at 3.5x2 c609-c610 150f-223k-2-fd cc 50v 0.022...

  • Page 50

    60 q611-q612 4851-241a-5 tr rn1241-a q613 4860-0770-5 tr 2sc2878 (apb) rl q614, q616, q618, q620 485a-114e-5 tr dta114esa rohm q622 4860-0050-5 tr ss8050 c/d samsung rl resistors j6123, j680 4701-682j-c rcf 1/8w 6.8k 5% ats r601-r606 4701-331j-c rcf 1/8w 330r 5% ats r607-r612 4701-104j-c rcf 1/8w 10...

  • Page 51

    61 power supply board assembly pc board 3002 * ah pcb-n0910c-psu pcb assy power supply n0910c 3002 * c pcb-n0911c-psu pcb assy power supply n0911c capacitors c758 8910-0091-0 cc 400v 0.01µf +-20% rl 17x9.5 c759 150f-223z-5-ug cc 50v 0.022µf +80/-20% rl 11x4 c760 157e-227m-5-pu ce 25v 220µf 20% rl 8....

  • Page 52

    62 speaker board assembly pc board 1501 * ah pcb-n0910c-spk pcb assy speaker n0910c 1501 * c pcb-n0911c-spk pcb assy speaker n0911c terminals 1502 * ah 2113-1663-0 4p speaker terminal r/b w/banana 1503 * ah 2113-1664-0 6p speaker terminal r/b w/banana 1502 * c 2113-1655-0 4p speaker terminal r/b 150...

  • Page 53

    63 c449 150f-103k-5-ii cc 50v 0.01µf 10% rl 5x5 c451 150f-122k-5-if cc 50v 1200pf 10% rl 5x3.5 c453 157f-105m-5-gm ce 50v 1µf 20% rl 4x7 c454 1551-0210-0 trimcap 5.2-30p tz03r300fr mur c456 15ch-220j-5-gg ctc 0/60 22pf 5% rl 4x4 c457 150f-682k-5-sf cc 50v 6800pf 10% rl 10x3.5 c462 157f-474m-5-gm ce ...

  • Page 54

    64 r425-r426 4701-102j-c rcf 1/8w 1k 5% ats r427 4701-680j-c rcf 1/8w 68r 5% ats r428 4701-333j-c rcf 1/8w 33k 5% ats r429 4701-104j-c rcf 1/8w 100k 5% ats r430 4701-471j-c rcf 1/8w 470r 5% ats r431 4701-222j-c rcf 1/8w 2.2k 5% ats r441 4701-102j-c rcf 1/8w 1k 5% ats r442 4701-222j-c rcf 1/8w 2.2k 5...

  • Page 55

    65 1001 * c pcb-n0911c-tun pcb assy tuner (c) n0911c jack 1002 2113-1805-0 6p rca jack r/w gold w/shield ant-terminal 1003 *ah 2107-0641-0 ant-terminal f-type aj-2019-040 1003 *c 2107-0681-0 ant-terminal (din-type) capacitors c381-c386 150f-101k-2-fc cc 50v 100pf 10% at 3.5x2 c901 * c 150f-223z-5-ug...

  • Page 56

    66 c988-c989 15ch-300j-5-ig ctc 0/60 30pf 5% rl 5x4 c990 157b-107m-5-km ce 6.3v 100µf 20% rl 6x7 c991 153f-102j-5-im cm 50v 1000pf 5% rl 5x7 c992 150f-103k-5-ii cc 50v 0.01µf 10% rl 5x5 zeners d901 4837-4c20-2 dz 1/2w 5.0-5.2v at d902 4837-7c20-2 dz 1/2w 9.1-9.5v at sockets j703b 2101-1801-0 socket ...

  • Page 57

    67 r388 4701-104j-c rcf 1/8w 100k 5% ats r389 4701-331j-c rcf 1/8w 330r 5% ats r901 *ah 4701-332j-c rcf 1/8w 3.3k 5% ats r901 *c 4701-333j-c rcf 1/8w 33k 5% ats r902 4701-220j-c rcf 1/8w 22r 5% ats r903 *ah 4701-102j-c rcf 1/8w 1k 5% ats r903 *c 4701-123j-c rcf 1/8w 12k 5% ats r904 *c 4701-331j-c rc...

  • Page 58

    68 u903 3131-3760-0 ic lc7218 pll freq synthesizer sanyo video board assembly pc board 1301 pcb-n0910c-vd pcb assy video n091xc jacks 1302 2113-1810-0 1p rca jack yl gold w/shield 1303 2113-1811-0 4p rca jack yl gold w/shield 1304 2113-1812-0 2p rca jack yl gold w/shield capacitors c441 150f-103k-2-...

  • Page 59

    69 resistors r4101-r4102 4701-331j-c rcf 1/8w 330r 5% ats r4103 4701-820j-c rcf 1/8w 82r 5% ats volume board assembly pc board 2001 pcb-n0910c-vol pcb assy volume n091xc wafer j207b 2102-031s-004 3 pin st. Wafer p=2.5 coulomb rotary m301 4750-6000-0 rotary encoder ec16b2425 alps trigger board assemb...

  • Page 60: Exploded View

    70 exploded view 0194 0194 0193 0138 m002 0182 0183 0205 0127 0126 0130 0143 0140 0139 0208 0142 0142 0148 0142 0148 0147 0146 0142 0144 0142 0141 0148 0148 0154 0154 0154 0148 0148 0148 0148 0148 0148 0162 0162 0146 0148 0148 0148 0147 0148 0148 0148 0148 0148 0148 0148 0148 0180 0181 0183 0182 ah ...

  • Page 61: Exploded View Parts List

    71 exploded view parts list item part no. Description qty 0101 1403-5160-1 bottom chassis 1 0102*ah 1403-6360-0 rear panel 120v 1 0102*c 1403-6361-0 rear panel 230v 1 0103 1403-5180-0 top cover 1 0104 1403-5190-2 sub-fascia 1 0105 1403-6350-0 fascia 1 0106 4154-0301-0 front input bezel 1 0107 4134-9...

  • Page 62

    0147 2954-3006-0000 3x6mm b-titl (yel.Zn) 3 0148 2954-3008-0000 tapping 3x8mm b-titl (yel.Zn) 58 0154 2954-2606-3000 screw bh 2.6x6 black 23 0162 2904-3006-0000 screw m3x6 3 0178 4152-5831-0 pcb support 12mm high 1 0180 2904-3010-3000 screw m3x10 (blk) 4 0181 2600-3005-0800 metal washer m3x0.5x8mm z...

  • Page 63: Packing Diagram

    73 packing diagram 45 44 43 36 37 38 36 41 42 40 39 46 item part no. Description q’ty 36 1490-2783-2 polyform endcap 2 37 1497-1072-4 unit polybag 1 38 1497-1162-0 fascia cover 1 39 4060-0530-0 batteries 2 40 2107-0661-1 300 ohm t antenna 1 41 8900-9710-1 remote control handset 1 42*ah 2103-6101-0 r...

  • Page 64: Ser

    Ser vice manual © nad 2001 t 751 surround sound receiver nad electronics international toronto.