NAD T 773 User manual

NAD
SERVICE MANUAL
T 773
T773
A/V Receiver
A/VReceiver
DRAFT DATE: 1 MAR 2004

2
SAFETY INFORMATION
AH VERSION
C VERSION

3
SERVICE SAFETY PRECAUTIONS
1. Replacing the fuses
CAUTION:
FOR CONTINUED PROTECTIONAGAINST THE RISK OF FIRE REPLACE ONLY WITH SAME TYPE OF
FUSE.
Reference Designator Part Number Description
F751*AH 33-0321111-00-88 FUSE 20A/250VAC SLOW BLOW 6X32mm
6S UL/CSA
F751*C 33-0161006-00-88 FUSE 10A/250VAC TIME-LAG 5X20mm
5D VDE/UL/CSA
F752*AH 33-0111006-00-88 FUSE 1.6A 250V TIME LAG 5x20mm 5T
UL/CSA/VDE/SEMKO
F752*C 33-0151006-00-88 FUSE 800mA 250V TIME LAG 5x20mm
5T UL/CSA/VDE/SEMKO
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.
CONTENTS
DESCRIPTION PAGE
SPECIFICATIONS............................................................................................................................ 4 - 5
REAR PANEL / FRONT PANEL VIEW .................................................................................................. 6
DISASSEMBLYINSTRUCTIONS .......................................................................................................... 7
WIRINGDIAGRAM................................................................................................................................ 8
BLOCKDIAGRAM................................................................................................................................. 9
SPECIALFUNCTION .......................................................................................................................... 10
DETAILS & WAVEFORMS ON SYSTEM & TEST & DEBUGGING .................................................... 10
ADJUSTMENT POINTS DIAGRAM /AMPLIFIERADJUSTMENT .......................................................11
PCB LAYOUT ............................................................................................................................... 12 - 25
SCHEMATICDIAGRAM ............................................................................................................... 26 - 45
ICBLOCKDIAGRAM ................................................................................................................... 46 - 54
EXPLODEDVIEW........................................................................................................................ 55 - 57
EXPLODED VIEW PARTS LIST................................................................................................... 58 - 59
ELECTRICALPARTS LIST .......................................................................................................... 60 - 73
PACKINGDIAGRAM .......................................................................................................................... 74
VERSIONHISTORY .......................................................................................................................... 75
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.

4
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) ≥≥
≥≥
≥- 72 dB
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 ≥≥
≥≥
≥55 dB
Subwoofer out, 500 mV in (THD at 2 V O/P, 100 Hz) ≤0.5 %
Crosstalk (500 mV input, 10 W, 1 kHz) ≥≥
≥≥
≥-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 ≥≥
≥≥
≥65 dB
Audio LPF ≥≥
≥≥
≥70 dB
A-WTD ≥≥
≥≥
≥70 dB
Channel Separation (1W,A-WTDFILTER) Track 65 997 Hz ≥≥
≥≥
≥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 ≥≥
≥≥
≥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 (2.2 V in, 1 W, w/ 80 kHz LPF, 1 kHz) ≤0.2 %

5
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 ≤≤
≤≤
≤0.08 %
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
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) ≤≤
≤≤
≤30 dBuV
S/N Ratio (5 mV in) ≥≥
≥≥
≥38 dB
THD (5 mV in) ≤≤
≤≤
≤3 %
IF Rejection (450 kHz) ≥≥
≥≥
≥36 dB
Image Rejection (F+2xIF) ≥≥
≥≥
≥28 dB
Selectivity ≥≥
≥≥
≥17 dB
Output 170 -20/+30 mV
Loop sensitivity (20 dB S/N)
999/1000 kHz ≤≤
≤≤
≤66 dB
603/600 kHz ≤≤
≤≤
≤66 dB
1404/1400 kHz ≤≤
≤≤
≤66 dB
Frequency Response (100 - 2.3 kHz, 5 mV) ± 6 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) ≤≤
≤≤
≤15 dBµV ≤≤
≤≤
≤15 dBuv
S/N Ratio (60 dB, IHF wtd) Mono ≥≥
≥≥
≥63 dB ≥≥
≥≥
≥63 dB
Stereo ≥≥
≥≥
≥63 dB ≥≥
≥≥
≥63 dB
Frequency Response (20 Hz - 15 kHz, 60 dBµ) 0 ± 1.5 dB 0 ± 1.5 dB
Channel Separation (60 dBµ) 100 Hz ≥≥
≥≥
≥30 dB ≥≥
≥≥
≥30 dB
1 k ≥≥
≥≥
≥38 dB ≥≥
≥≥
≥38 dB
10 kHz ≥≥
≥≥
≥30 dB ≥≥
≥≥
≥30 dB
Alternate Channel Selectivity (40 dBµ, ± 400 kHz) ≥≥
≥≥
≥60 dB ≥≥
≥≥
≥45 dB
Capture Ratio (40 dBµ) ≤≤
≤≤
≤3 dB ≤≤
≤≤
≤3 dB
AM Suppression (60 dBµ, 100% Mod. FM, 30% Mod. AM) ≥≥
≥≥
≥48 dB ≥≥
≥≥
≥48 dB
Image Rejection (119.4 MHz) −−
−−
−≥≥
≥≥
≥65 dB
I.F. Rejection (10.7 MHz) ≥≥
≥≥
≥78 dB −−
−−
−
Pilot Suppression (98 MHz) ≥≥
≥≥
≥60 dB ≥≥
≥≥
≥60 dB
THD (60 dBµ, L=R 75 kHz for AH, 40 kHz Dev for C) Mono ≤≤
≤≤
≤0.25 % ≤≤
≤≤
≤0.25 %
Stereo ≤≤
≤≤
≤0.35 % ≤≤
≤≤
≤0.35 %
Auto-Search Sensitivity On ≥≥
≥≥
≥24 dBµ ≥≥
≥≥
≥24 dBµ
Off ≤≤
≤≤
≤15 dBµ ≤≤
≤≤
≤15 dBµ
RDS decode Sensitivity ≤≤
≤≤
≤26 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)

6
FRONT PANEL
REAR PANEL / FRONT PANEL VIEW
REAR PANEL
1. FM &AM ANTENNA
2. IR INPUT & OUTPUT
3. +12V TRIGGER INPUT & OUTPUT
4. SOFTCLIPPING ON/OFF
5. MS OUT (MULTISOURCE OUT)
6. MONITOR OUT
7. CD INPUT
8. COMPONENT VIDEO IN &
COMPONENT VIDEO OUT
9. DIGITALAUDIO INPUT &
DIGITALAUDIO OUTPUT
10. RS-232
11. POWER SWITCH
12. SWITCHEDAC OUTLETS
13. AC POWER INLET
14. SPEAKERSA& 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)
11. VIDEO &AUDIO
12. TAPE MONITOR
13. DIGITALAUDIOSELECTOR
14. EXT. 7.1
15. SURROUND MODE
16. LEVELS
17. TONE CONTROLS
18. TONE DEFEAT
19. SPEAKERSA& B
20. VIDEO 6 INPUT
21. PHONES

7
DISASSEMBLY INSTRUCTIONS
1. Remove machine screws M4.0 x 8.0 (1to 8) from the side panels.
Remove tapping screw 3.0 x 8.0 (9to 12) from the back panel.
Refer to Figure No. 1.
1
2
3
4
8
9
10
11
12
5
6
7
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. 1
14
13
13
Figure No. 2

8a
WIRING DIAGRAM

8b
THERM SENSNOR
UL VERSION :
USE J758, J759
CE VERSION :
USE J760
3 PCS
2 PCS
36-2828201-71-XX FFC CABLE 28 PINS P1.25 L=200mm
82-0226135-04-XX CABLE ASSY 2 WAYS 2.5P UL1533 L=540mm
82-0426135-03-XX CABLE ASSY 4 WAYS 2.5P UL2468 L=540mm
36-1728201-71-XX FFC CABLE 17 PINS P1.25 L=200mm
36-2028201-71-XX FFC CABLE 20 PINS P1.25 L=200mm
TO MAIN BOARD
TO MAIN BOARD
82-3028061-71-XX FFC CABLE 30 PINS P1.25 L=60mm
82-1026135-01-XX CABLE ASSY 10 WAYS #26 2.5P UL2877 L=540mm
TO MAIN BOARD
82-0826135-04-XX CABLE ASSY 8 WAYS #26 2.5P UL2468 L=380mm
TO MAIN BOARD
TO MAIN BOARD
82-0426135-01-XX CABLE ASSY 4 WAYS #26 2.5P UL2877 L=500mm
82-0626135-07-XX
CABLE ASSY 6 WAYS #26 2.5P
L=480mm
82-0426135-07-XX CABLE ASSY 4 WAYS #26 2.5P L=450mm
82-0326135-08-XX CABLE ASSY 3 WAYS #26 UL2854 L=300mm
82-1226135-06-XX CABLE ASSY 12 WAYS #26 2.5P L=290mm
82-0426135-05-XX CABLE ASSY 4 WAYS #26 2.5P UL2468 L=400mm
FROM TRANSFORMER
82-0826135-05-XX CABLE ASSY 8 WAYS #26 2.5P UL1533 L=340mm
82-0626135-04-XX CABLE ASSY 6 WAYS #26 2.5P UL1533 L=540mm
82-0618235-02-XX CABLE ASSY 6 WAYS #18 UL1007 L=170mm
82-1426135-00-XX CABLE ASSY 14 WAYS #26 2.5P UL2877 L=420mm
82-0518235-07-XX, CABLE ASSY 5 WAYS #18
3.96P UL1007 L=320mm (BK/W/BL)
82-0626135-06-XX CABLE ASSY 6 WAYS #26 2.5P UL2468 L=320mm
82-0418235-00-XX CABLE ASSY 4 WAYS #18 3.96P UL1007 L=200mm
82-0418235-04-XX
CABLE ASSY 4 WAYS #18 3.96P
UL1007 L=320mm
T773 WIRE DIAGRAM DATE : 17/05/04 REV. B
82-0426135-00-XX CABLE ASSY 4 WAYS #26 2.5P UL2877 L=200mm
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
82-0226135-02-XX
CABLE ASSY 2 WAYS #26 2.5P UL2468
L=340mm
82-0226135-03-XX
CABLE ASSY 2 WAYS #26 2.5P UL2468
L=440mm
82-0218235-01-XX, CABLE ASSY 2 WAYS #18 UL1007 L=170mm
82-0618235-01-XX, CABLE ASSY 6 WAYS #18 UL1007 L=140mm
82-0318235-06-XX
CABLE ASSY 3 WAYS #18 3.96P
UL1015 L=350mm
82-0116436-08-XX CABLE ASSY 1 WAY #16 UL1015 GREEN/YELLOW L=100mm CHASSIS GND
82-0526135-01-XX CABLE ASSY 5 WAYS #26 2.5P UL2468 L=150MM
36-2828161-71-XX
FFC CABLE 28 PINS P1.25
L=160mm
82-0418235-05-XX CABLE ASSY 4 WAYS #18 3.96P UL1007 L=420mm
82-0418235-01-XX CABLE ASSY 4 WAYS #18 3.96P UL1007 L=280mm
82-0318235-03-XX
CABLE ASSY 3 WAYS #18 3.96P
UL1007 L=180mm
82-0116436-12-XX CABLE ASSY 1 WAYS #16 UL1672 BROWN L=100mm
82-0116438-03-XX CABLE ASSY 1 WAYS #16 UL1672 BLUE L=100mm
82-0518235-06-XX, CABLE ASSY 5 WAYS #18 3.96P
UL1007 L=120mm (R/BK/BR/O)
82-0518235-04-XX, CABLE ASSY 5 WAYS #18 3.96P UL1007 L=250mm (V/BL/Y)
82-0418235-00-XX, CABLE ASSY
4 WAYS #18 3.96P UL1007
L=200mm
82-0118435-00-XX CABLE ASSY 1 WAY #18 UL1007 BLACK L=100mm W/ RING TERMINAL
82-0118435-01-XX CABLE ASSY 1 WAY #18 UL1007 BLACK L=360mm W/ RING TERMINAL
82-0118435-00-XX CABLE ASSY 1 WAY #18 UL1007 BLACK L=100mm W/ RING TERMINAL
KEYBOARD
MAIN BOARD
TRIGGER BOARD
POWER SWITCH
BOARD
J702B J8101B
J713A J714A
J715A
J719A
J720A
J717A
J710A
J711A
J712A
J708A
J707A
J704A
J502B
J721A J709A
J713B J714B
J203A
J204B J350B
J901B
J753B
VIDEO 6 INPUT
BOARD
J757B
J756B
PSU BOARD
COMPONENT VIDEO
BOARD
DIGITAL
BOARD
AUDIO BOARD
VIDEO BOARD
J1009A
J1010A
TUNER
PRE-OUT BOARD MULTI-CHANNEL
BOARD
J717B
J611A J612A
J719B
J6104A
J708AB
J707B
J350A
J414B
J710B J711B J712B
J414A
SECONDARY BOARD
ISC-S
BOARD
J8202B J8102B J581A
J781A
J782A
J582A
J8101A
J8103A
J811B
J705B
S-VIDEO BOARD
AMP S BOARD
AMP FR BOARD
J612B
J502A
J503A
M506
J873
J511A
J781B
J503B
J611B
J801A
J811A
J753A
J754B
J751B
J504A
J501A
J702A
J874
J757 J756
J761_N J761_L
J760
J758
J759
J8205B J8105B
J901A
SPEAKER
BOARD
J8204A
J8202A J8205A
ISC-F
BOARD
J8102A J8105A
J8104A
J511B
J6101B
J6102A J6103A
J6101A
J6103B J6102B
J509A
J875
J505B
J505A
J581B
J3103BJ721B J709B
LED BOARD
DSP BOARD
J715B J604B
J203B
J1010B J1009B
J205 J206
J509B
J3103A
J872
J871
J201
J701
J6106B
J6105B
J6106A J6105A
WIRING DIAGRAM

9
BLOCK DIAGRAM

10
SPECIALFUNCTION
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
DETAILS & WAVEFORMS ON SYSTEM TEST & DEBUGGING
T89C51RD2 (U202) main clock is at 20MHz (X202)
T89C51RD2 (U201) main clock is at 20MHz (X201)
UPPER - +5V supply to KEYBOARD when power up
LOWER - RESET line (TCM810LENB713) when
power up
UPPER - OUTPUT ENABLE (pin 24) of EPROM
(W27C02) when changing SURROUND MODES
LOWER - CHIP ENABLE (pin 22) of EPROM
(W27C02) when changing SURROUND MODES
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.

11
R522 R545 R571 R835
P501 P502 P503
R835 R836 R897
P802P801
P803
J511B
J811B
AMPLIFIERADJUSTMENT
Idle Current
1. Rotate R522 fully clockwise.
2. Connect DC millivoltmeter to P501 (i.e. Across half of R523, 0.22 Ohm resistor).
3. Turn on the unit.
4. Adjust R522 for 2mV reading on voltmeter.
5. Leave power on for at least 5 min, and check for idle current again.
6. Repeat for other channels.
(IN FRONT POWER AMP PCB)
CHANNEL JUMPER VR
FL P502 R545
FR P53 R571
C P503 R571
BSR P501 R522
(IN SURROUND POWER AMP PCB)
CHANNEL JUMPER VR
SL P801 R835
SR P802 R836
BSL P803 R897
ISC Sensitivity
Rotate J511B & J811B fully clockwise.
ADJUSTMENTPOINT DIAGRAM
FRONT/CENTER AMPLIFIER BOARD
SURROUND AMPLIFIER BOARD
ISC FRONT AMP BOARD ISC SURROUND AMP BOARD

12
PCBLAYOUT
AUDIO BOARD - COMPONENT SIDE
AUDIO BOARD - COPPER SIDE

13
COMPONENT VIDEO BOARD - COMPONENT SIDE
COMPONENT VIDEO BOARD - COPPER SIDE
DIGITAL BOARD - COMPONENT SIDE
DIGITAL BOARD - COPPER SIDE

14
DSP BOARD - COPPER SIDE
DSP BOARD - COMPONENT SIDE

15
FRONT/CENTER AMPLIFIER BOARD - COMPONENT SIDE

16
FRONT/CENTER AMPLIFIER BOARD - COPPER SIDE

17
SURROUND AMPLIFIER BOARD - COMPONENT SIDE

18
SURROUND AMPLIFIER BOARD - COPPER SIDE

19
KEY BOARD / LED BOARD
- COMPONENT SIDE KEY BOARD / LED BOARD - COPPER SIDE