NAD T-773 Service manual

DRAFT DATE: 1 MAR 2004

NAD

SERVICE MANUAL

T 773

A/V Receiver

T 773

SAFETY INFORMA TION

AH VERSION

C VERSION

SERVICE SAFETY PRECAUTIONS

1. Replacing the fuses

CAUTION:

FOR CONTINUED PROTECTION AGAINST THE RISK OF FIRE REPLACE ONLY WITH SAME TYPE OF FUSE.

Reference Designator Part Number Description

F751*AH

F751*C

F752*AH

F752*C

NOTE:

<*AH > : USA, CANADIAN MODEL ONLY. <*C > : EUROPEAN MODEL ONLY.

2. Safety check out

(Only U.S.A. model) Before returning the product to the customer, make leakage current or resistance measurements to determine

that exposed parts are acceptably insulated from supply circuit.

33-0321111-00-88 FUSE 20A/250VAC SLOW BLOW 6X32mm

6S UL/CSA

33-0161006-00-88 FUSE 10A/250VAC TIME-LAG 5X20mm

5D VDE/UL/CSA

33-0111006-00-88 FUSE 1.6A 250V TIME LAG 5x20mm 5T

UL/CSA/VDE/SEMKO

33-0151006-00-88 FUSE 800mA 250V TIME LAG 5x20mm

5T UL/CSA/VDE/SEMKO

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

DESCRIPTION PAGE

SPECIFICATIONS............................................................................................................................ 4 - 5

REAR PANEL / FRONT P ANEL VIEW .................................................................................................. 6

DISASSEMBL Y INSTRUCTIONS.......................................................................................................... 7

WIRING DIAGRAM................................................................................................................................ 8

BLOCK DIAGRAM................................................................................................................................. 9

SPECIAL FUNCTION .......................................................................................................................... 10

DETAILS & WAVEFORMS ON SYSTEM & TEST & DEBUGGING .................................................... 10

ADJUSTMENT POINTS DIAGRAM / AMPLIFIER ADJUSTMENT .......................................................11

PCB LAYOUT............................................................................................................................... 12 - 25

SCHEMA TIC DIAGRAM ............................................................................................................... 26 - 45

IC BLOCK DIAGRAM ................................................................................................................... 46 - 54

EXPLODED VIEW........................................................................................................................ 55 - 57

EXPLODED VIEW PAR TS LIST................................................................................................... 58 - 59

ELECTRICAL P AR TS LIST .......................................................................................................... 60 - 73

PACKING DIAGRAM.......................................................................................................................... 74

VERSION HISTORY .......................................................................................................................... 75

SPECIFICATIONS

POWER AMPLIFIER SECTION

Rated distortion (Rated power level into 8 ohms, THD 20 Hz-20 kHz FL/C/FR) ≤ 0.1 %

(Rated power level into 8 ohms, THD 20 Hz-20 kHz SL/SR/BS) ≤ 0.1 %

Input Sensitivity (ref. 8 ohms, 1 kHz) 166 ± 20 mV

S/N Ratio (A-wtd, 1kHz, 1 W, 8 ohm, SL/SR/BL)

Frequency Response (20 Hz - 20 kHz) 0 ± 1.0 dB Channel Balance (1 dB to -40 dB, 1 kHz) ≤ 2 dB

(-41 dB to -50 dB, 1 kHz) ≤ 3 dB Audio muting at 1 kHz Subwoofer out, 500 mV in (THD at 2 V O/P, 100 Hz) ≤ 0.5 % Crosstalk (500 mV input, 10 W, 1 kHz)

≥≥

≥ - 72 dB

≥≥

≥ 55 dB

≥≥

≥ -57 dB

≥≥

Controls

Bass (at 500 mV in, 1 W out, 100 Hz) ± 10 dB ± 2 dB Treble (at 500 mV in, 1 W out, 10 kHz) ± 10 dB ± 2 dB

DOLBY DIGITAL SECTION

Channel Difference(FL ref. Track 30) ± 1.2 dB Frequency Resporse at Dolby config.2 SL Track 46 200 - 20 kHz ± 0.8 dB

SR Track 47 200 - 20 kHz ± 0.8 dB C Track 44 200 - 20 kHz ± 0.8 dB

Harmonic Distortion (1 W, Audio LPF, Dolby Congfig 1) FL Track 65 997 Hz ≤ 0.08 %

FR Track 67 997 Hz ≤ 0.08 % SL Track 68 997 Hz ≤ 0.08 % SR Track 69 997 Hz ≤ 0.08 % C Track 66 997 Hz ≤ 0.08 %

S/N Ratio (TRACK 30 for O/P 1 W , FAUSE) CCIR / ARM

Audio LPF A-WTD

Channel Separation (1 W, A-WTD FILTER) Track 65 997 Hz

≥≥

≥ 65 dB

≥≥ ≥≥

≥ 70 dB

≥≥ ≥≥

≥ 70 dB

≥≥ ≥≥

≥ 60 dB

≥≥

DOLBY PRO LOGIC II SECTION

Frequency Resporse

I/P mode : L, R : 1 V in, 1 W, Ch L/R 40 Hz 0 ± 2.0 dB

20 kHz 0 ± 2.0 dB

I/P mode : L=R : 1 V in, 1 W, Ch /L/R 40 Hz 0 ± 2.0 dB

Ch C 20 kHz 0 ± 2.0 dB I/P mode : L=-R : 1 V in, 1 W, Ch SL/SR 40 Hz 0 ± 2.0 dB

20 kHz 0 ± 2.0 dB S/N Ratio (200 mV in, 1 W, A-WTD w/ 1 k termination) I/P mode : L, R : 1 kHz, Ch L/R I/P mode : L=R : 1 kHz, Ch C I/P mode : L=-R : 1 kHz, Ch SL/SR THD (2.2 V in, 1 W, w/ 80 kHz LPF, 1 kHz) ≤ 0.2 %

≥≥

≥ 65 dB

≥≥ ≥≥

≥ 65 dB

≥≥ ≥≥

≥ 65 dB

≥≥

DTS SECTION

Output Level (Vol 0 dB) : FL/FR/C/SL/SR Track 6 1 kHz 0.3 ± 1.3 W Channel Difference (FL ref) : FL/FR/C/SL/SR Track 6 1 kHz ± 1.0 dB Harmonic Distortion (Audio Filter) : FL/FR/C/SL/SR Track 10-14 1 kHz Frequency Response (20 Hz to 20 kHz) Track 26-30 +2/-1.5 dB Subwoofer Output Level 1 kHz ref at pre-out (FL) Play Track 10, charge to 15 12.5 ± 1.5 dB

≤≤

≤ 0.08 %

≤≤

AM TUNER SECTION

Input level is expressed as the reading in open circuit of 75-ohm source impedance signal generator Usable sensitivity (999/1000 kHz) S/N Ratio (5 mV in) THD (5 mV in) IF Rejection (450 kHz) Image Rejection (F+2xIF) Selectivity Output 170 -20/+30 mV Loop sensitivity (20 dB S/N)

999/1000 kHz 603/600 kHz 1404/1400 kHz

Frequency Response (100 - 2.3 kHz, 5 mV) ± 6 dB

≤≤

≤ 30 dBuV

≤≤ ≥≥

≥ 38 dB

≥≥ ≤≤

≤ 3 %

≤≤ ≥≥

≥ 36 dB

≥≥ ≥≥

≥ 28 dB

≥≥ ≥≥

≥ 17 dB

≥≥

≤≤

≤ 66 dB

≤≤ ≤≤

≤ 66 dB

≤≤ ≤≤

≤ 66 dB

≤≤

FM TUNER SECTION *C *AH

Input level is expressed as the reading in open circuit of 75-ohm source impedance signal generator Usable sensitivity (98 MHz) S/N Ratio (60 dB, IHF wtd) Mono

Stereo Frequency Response (20 Hz - 15 kHz, 60 dBµ) 0 ± 1.5 dB 0 ± 1.5 dB Channel Separation (60 dBµ) 100 Hz

1 k

10 kHz Alternate Channel Selectivity (40 dBµ, ± 400 kHz) Capture Ratio (40 dBµ) AM Suppression (60 dBµ, 100% Mod. FM, 30% Mod. AM) Image Rejection (119.4 MHz) I.F. Rejection (10.7 MHz) Pilot Suppression (98 MHz) THD (60 dBµ, L=R 75 kHz for AH, 40 kHz Dev for C) Mono

Stereo Auto-Search Sensitivity On

Off RDS decode Sensitivity

≤≤

≤ 15 dBµV

≤≤ ≥≥

≥ 63 dB

≥≥ ≥≥

≥ 63 dB

≥≥

≥ 30 dB

≥≥ ≥≥

≥ 38 dB

≥≥ ≥≥

≥ 30 dB

≥≥ ≥≥

≥ 60 dB

≥≥ ≤≤

≤ 3 dB

≤≤ ≥≥

≥ 48 dB

≥≥

−−

−

−− ≥≥

≥ 78 dB

≥≥ ≥≥

≥ 60 dB

≥≥ ≤≤

≤ 0.25 %

≤≤ ≤≤

≤ 0.35 %

≤≤ ≥≥

≥ 24 dBµ

≥≥ ≤≤

≤ 15 dBµ

≤≤ ≤≤

≤ 26 dBµ

≤≤

≤ 15 dBuv

≤≤ ≥≥

≥ 63 dB

≥≥ ≥≥

≥ 63 dB

≥≥

≥ 30 dB

≥≥ ≥≥

≥ 38 dB

≥≥ ≥≥

≥ 30 dB

≥≥ ≥≥

≥ 45 dB

≥≥ ≤≤

≤ 3 dB

≤≤ ≥≥

≥ 48 dB

≥≥ ≥≥

≥ 65 dB

≥≥

−−

−

−− ≥≥

≥ 60 dB

≥≥ ≤≤

≤ 0.25 %

≤≤ ≤≤

≤ 0.35 %

≤≤ ≥≥

≥ 24 dBµ

≥≥ ≤≤

≤ 15 dBµ

≤≤

−−

−

−−

PHYSICAL SPECIFICATIONS

Dimensions (Width x Height x Depth) 435 x 195 x 423 mm Net Weight 24 Kg (52.80 lbs) Shipping Weight 30.7 Kg (67.50 lbs)

REAR PANEL / FRONT PANEL VIEW

REAR PANEL

1. FM & AM ANTENNA

2. IR INPUT & OUTPUT

3. +12V TRIGGER INPUT & OUTPUT

4. SOFT CLIPPING ON/OFF

5. MS OUT (MULTISOURCE OUT)

6. MONITOR OUT

7. CD INPUT

8. COMPONENT VIDEO IN & COMPONENT VIDEO OUT

9. DIGITAL AUDIO INPUT & DIGITAL AUDIO OUTPUT

FRONT PANEL

10. RS-232 1 1. POWER SWITCH

12. SWITCHED AC OUTLETS

13. AC POWER INLET

14. SPEAKERS A & B

15. DVD, SAT, VCR, VIDEO 4 & VIDEO 5

16. MAIN IN / AUDIO PRE-OUTS / SUBWOOFER OUT

17. TAPE INPUT & OUTPUT

18. DISC INPUT

19. 7.1 CH. INPUTS

1. STANDBY SWITCH

2. STANDBY LED

3. AM / FM

6. FM MUTE / MODE

4. DISPLAY

5. MEMORY

7. PRESET DOWN / UP

8. SEARCH DOWN / UP

9. VFL DISPLAY

10. VOLUME (SETUP) 1 1. VIDEO & AUDIO

12. TAPE MONITOR

13. DIGITAL AUDIO SELECTOR

14. EXT. 7.1 6

15. SURROUND MODE

16. LEVELS

17. TONE CONTROLS

18. TONE DEFEAT

19. SPEAKERS A & B

20. VIDEO 6 INPUT

21. PHONES

DISASSEMBLY INSTRUCTIONS

1. Remove machine screws M4.0 x 8.0 (1 to 8) from the side panels. Remove tapping screw 3.0 x 8.0 (9 to 12) from the back panel. Refer to Figure No. 1.

Figure No. 1

2. Pull both sides of the TOP COVER slightly outwards 13 and tilt approx. 35 ° and then remove in the direction as indicated by the arrow 14. Refer to Figure No. 2.

Figure No. 2

WIRING DIAGRAM

TUNER

J414B

BOARD

COMPONENT VIDEO

J711B

J712B

S-VIDEO BOARD

36-1728201-71-XX

FFC CABLE 17 PINS P1.25

L=200mm

TRIGGER BOARD

82-0826135-04-XX

CABLE ASSY 8 WAYS #26 2.5P UL2468

J710B

J705B

J350A

L=380mm

TO MAIN BOARD

J414A

TO MAIN BOARD

82-1026135-01-XX

CABLE ASSY 10 WAYS #26 2.5P UL2877

L=540mm

36-2828161-71-XX

FFC CABLE 28 PINS P1.25

L=160mm

TO MAIN BOARD

J6105A

J6106A

J6103A

BOARD

MULTI-CHANNEL

J6102A

J719B

J6101A

TO MAIN BOARD

J717B

J6104A

36-2028201-71-XX

FFC CABLE 20 PINS P1.25 L=200mm

82-0426135-01-XX

CABLE ASSY 4 WAYS #26 2.5P

UL2877 L=500mm

J707B

J901A

J708AB

TO MAIN BOARD

BOARD

DIGITAL

J1009A

J1010A

J1009B

82-0226135-04-XX

CABLE ASSY 2 WAYS 2.5P UL1533

L=540mm

82-0426135-03-XX

J1010B

CABLE ASSY 4 WAYS 2.5P UL2468

L=540mm

T773 WIRE DIAGRAM DATE : 17/05/04 REV. B

DSP BOARD

PRE-OUT BOARD

82-3028061-71-XX

FFC CABLE 30 PINS P1.25

L=60mm

J611A

J612A

J720A

J6105B

J719A

J6106B

J712A

J707A

J711A

J710A

J708A

J704A

J502B

J6101B

J715A

J717A

J721A

J714A

J713A

MAIN BOARD

J709A

J702B J8101B

J701

VIDEO BOARD

82-0826135-05-XX

CABLE ASSY 8 WAYS #26 2.5P

UL1533 L=340mm

82-0118435-01-XX

CABLE ASSY 1 WAY #18 UL1007 BLACK

L=360mm W/ RING TERMINAL

82-0426135-00-XX

82-0626135-04-XX

CABLE ASSY 6 WAYS #26 2.5P

CABLE ASSY 4 WAYS #26 2.5P UL2877

L=200mm

UL1533 L=540mm

J203B

J715B

J604B

82-0326135-08-XX

CABLE ASSY 3 WAYS #26

UL2854 L=300mm

82-0118435-00-XX

CABLE ASSY 1 WAY #18

UL1007 BLACK L=100mm W/

RING TERMINAL

J201

J702A

J203A

J713B J714B

36-2828201-71-XX

FFC CABLE 28 PINS P1.25

L=200mm

2 PCS

3 PCS

82-0116438-03-XX

82-0116436-08-XX

CABLE ASSY 1 WAY #16 UL1015

GREEN/YELLOW L=100mm

CHASSIS GND

82-0116438-03-XX

CABLE ASSY 1 WAYS #16

UL1672 BLUE L=100mm

82-0116436-12-XX

CABLE ASSY 1 WAYS #16

UL1672 BROWN L=100mm

J757B

J756B

AUDIO BOARD

82-0518235-04-XX, CABLE ASSY

5 WAYS #18 3.96P UL1007

L=250mm (V/BL/Y)

BOARD

SPEAKER

82-0318235-06-XX

82-0116436-12-XX

CABLE ASSY 1 WAYS #16

UL1672 BROWN L=100mm

CABLE ASSY 1 WAYS #16

UL1672 BLUE L=100mm

CE VERSION :

UL VERSION :

USE J758, J759

J3103A

J6103B

J6102B

L=200mm

4 WAYS #18 3.96P UL1007

82-0418235-00-XX, CABLE ASSY

UL1015 L=350mm

CABLE ASSY 3 WAYS #18 3.96P

UL1007 L=120mm (R/BK/BR/O)

82-0518235-06-XX, CABLE ASSY 5 WAYS #18 3.96P

J759

J758

J761_N J761_L

USE J760

J760

BOARD

POWER SWITCH

THERM SENSNOR

J511A

3.96P UL1007 L=320mm (BK/W/BL)

82-0518235-07-XX, CABLE ASSY 5 WAYS #18

J756

J753A

J757

J754B

PSU BOARD

J751B

M506

J501A

J504A

J801A

J811A

UL1007 L=320mm

82-0418235-04-XX

CABLE ASSY 4 WAYS #18 3.96P

J505B

J581B

82-0418235-05-XX

J873

J875

J874

82-0418235-01-XX

J505A

L=440mm

L=340mm

82-0226135-03-XX

82-0226135-02-XX

CABLE ASSY 2 WAYS #26 2.5P UL2468

CABLE ASSY 4 WAYS #18

3.96P UL1007 L=420mm

J611B

CABLE ASSY 4 WAYS #18

3.96P UL1007 L=280mm

J511B

ISC-F

BOARD

J8103A

82-0626135-06-XX

CABLE ASSY 6 WAYS #26

2.5P UL2468 L=320mm

J503B

AMP S BOARD

J8104A

J8102A J8105A

J8101A

J509A

AMP FR BOARD

J503A

J781B

J502A

J811B

ISC-S

BOARD

J612B

J871

J872

J509B

J8204A

J8202A J8205A

FROM TRANSFORMER

82-1226135-06-XX

CABLE ASSY 12 WAYS #26 2.5P L=290mm

UL1007 L=180mm

82-0318235-03-XX

82-0418235-00-XX

CABLE ASSY 4 WAYS #18 3.96P

UL1007 L=200mm

CABLE ASSY 3 WAYS #18 3.96P

82-0618235-01-XX, CABLE ASSY 6 WAYS

82-0218235-01-XX, CABLE ASSY 2 WAYS

#18 UL1007 L=170mm

L=480mm

82-0626135-07-XX

CABLE ASSY 6 WAYS #26 2.5P

82-0426135-07-XX

CABLE ASSY 4 WAYS #26 2.5P

82-1426135-00-XX

CABLE ASSY 14 WAYS #26 2.5P UL2877

L=420mm

J782A

SECONDARY BOARD

#18 UL1007 L=140mm

L=450mm

J582A

J8205B J8105B

J205 J206

J901B

J781A

J753B

J350B

J204B

82-0426135-05-XX

CABLE ASSY 4 WAYS #26 2.5P

UL2468 L=400mm

82-0618235-02-XX

CABLE ASSY 6 WAYS #18 UL1007

J8202B J8102B J581A

KEYBOARD

L=170mm

J3103BJ721B J709B

82-0526135-01-XX

LED BOARD

82-0118435-00-XX

CABLE ASSY 1 WAY #18

UL1007 BLACK L=100mm W/

RING TERMINAL

BOARD

VIDEO 6 INPUT

CABLE ASSY 5 WAYS #26

2.5P UL2468 L=150MM

BLOCK DIAGRAM

SPECIAL FUNCTION

FEATURE KEYS PRESS ON FRONT PANEL

RESET FOR AH VERSION VIDEO + TONE DEFEAT RESET FOR C VERSION VIDEO + TONE CONTROLS NTSC / PAL SELECTION VIDEO + MEMORY VFD ALL DISPLAY AUDIO + TAPE MONITOR AM FREQ. STEP AM/FM + FM MUTE

DET AILS & W A VEFORMS ON SYSTEM TEST & DEBUGGING

T89C51RD2 (U202) main clock is at 20MHz (X202)

UPPER - OUTPUT ENABLE (pin 24) of EPROM (W27C02) when changing SURROUND MODES

LOWER - CHIP ENABLE (pin 22) of EPROM (W27C02) when changing SURROUND MODES

T89C51RD2 (U201) main clock is at 20MHz (X201)

UPPER - +5V supply to KEYBOARD when power up LOWER - RESET line (TCM810LENB713) when

power up

SCLK (pin 43 of CS49326)

LRCLK (pin 42 of CS49326)

MCLK (pin 30 of CS49326)

NOTE: The waveforms are based on software version V1.26.