NAD T 773 User manual

NAD
SERVICE MANUAL
T 773
T 773
PHASE II & VC
A/V Receiver
DRAFT DATE: 14 SEPTEMBER 2005

2
SAFETY INFORMATION
AH VERSION
C VERSION

3
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 SCM Part Number Description
F751*AH 370-019100-00(2) 33-0321111-00-88 FUSE 10A 250VAC SLOW BLOW
5X20mm 5T UL/CSA
F751*C 370-016100-04(9) 33-0161006-00-88 FUSE 10A 250VAC TIME-LAG
5X20mm 5D VDE/UL/CSA
F752*AH 370-011100-06(4) 33-0111006-00-88 FUSE 1.6A 250V TIME LAG
5X20mm 5T UL/CSA/VDE/SEMKO
F752*C 370-015100-02(2) 33-0151006-00-88 FUSE 800mA 250V TIME LAG
5X20mm TSD 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
DISASSEMBLY INSTRUCTIONS .......................................................................................................... 7
WIRING DIAGRAM ......................................................................................................................... 8 - 10
BLOCK DIAGRAM ................................................................................................................................ 11
SPECIAL FUNCTION .......................................................................................................................... 12
DETAILS & WAVEFORMS ON SYSTEM & TEST & DEBUGGING .................................................... 12
ADJUSTMENT POINTS DIAGRAM / AMPLIFIER ADJUSTMENT ...................................................... 13
PCB LAYOUT ............................................................................................................................... 14 - 25
SCHEMATIC DIAGRAM ............................................................................................................... 26 - 43
IC BLOCK DIAGRAM ................................................................................................................... 44 - 52
EXPLODED VIEW & EXPLODED VIEW PARTS LIST ................................................................ 53 - 55
EXPLODED VIEW & EXPLODED VIEW PARTS LIST - FANS & HEATSINK .............................. 56 - 57
EXPLODED VIEW & EXPLODED VIEW PARTS LIST - TRANSFORMER ......................................... 58
ELECTRICAL PARTS LIST .......................................................................................................... 59 - 72
PACKING DIAGRAM .......................................................................................................................... 73
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) 387 ±±
±±
±20 mV
S/N Ratio (A-wtd, 1kHz, 1 W, 8 ohm, SL/SR/BL) ≥≥
≥≥
≥- 75dB
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 (1 W, A-WTD FILTER) 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 dBμμ
μμ
μ≤≤
≤≤
≤15 dBμμ
μμ
μv
S/N Ratio (60 dB, IHF wtd) Mono ≥≥
≥≥
≥63 dB ≥≥
≥≥
≥63 dB
Stereo ≥≥
≥≥
≥63 dB ≥≥
≥≥
≥63 dB
Frequency Response (20 Hz - 15 kHz, 60 dBμμ
μμ
μ)0±±
±±
±1.5 dB 0 ±±
±±
±1.5 dB
Channel Separation (60 dBμμ
μμ
μ) 100 Hz ≥≥
≥≥
≥30 dB ≥≥
≥≥
≥30 dB
1 k ≥≥
≥≥
≥38 dB ≥≥
≥≥
≥38 dB
10 kHz ≥≥
≥≥
≥30 dB ≥≥
≥≥
≥30 dB
Alternate Channel Selectivity (40 dBμμ
μμ
μ,±400 kHz) ≥≥
≥≥
≥60 dB ≥≥
≥≥
≥45 dB
Capture Ratio (40 dBμμ
μμ
μ)≤≤
≤≤
≤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 dBμμ
μμ
μ, 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 dBμμ
μμ
μ≥≥
≥≥
≥24 dBμμ
μμ
μ
Off ≤≤
≤≤
≤15 dBμμ
μμ
μ≤≤
≤≤
≤15 dBμμ
μμ
μ
RDS decode Sensitivity ≤≤
≤≤
≤26 dBμμ
μμ
μ−−
−−
−
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
FM
FRONT
LFRONT
R
FRONT SURR SURR-B SUBW DISC
SURR
LSURR
R
SURR-BACK
LSURR-BACK
R
SUBW 1CENTER
RL
GND AM
TRIGGER
AUTOOFF
SOFT CLIPPING
ON
OFF
1
1
C
B C R YC B C R Y
2
C B C R Y
3
C B C R Y
23456
ANTENNA
VIDEO 5
VIDEO 4
SUBW 2
AUDIO
PRE-OUT
TAPE
VCR
SAT
DVD
MONITOR
OUT
7.1 CH INPUT
OUT
IN
OUT OUT
1 2 3
IN IN
IN
OUT
IN
OUT
IN
IN
IN
COMPONENT VIDEO OUT
DIGITAL OUT DIGITAL IN
SPEAKER A
LR
FRONT
LR
SURROUND
LR
SURR-BACK
LR
CENTER
SWITCHED
120V ~60Hz AC OUTLET
120V ~60Hz
120W 1A MAX
SPEAKER B
RS-232
OPTICAL COAXIAL
COMPONENT VIDEO IN
IR +12V TRIGGER
Serial No./No. De Series
CAUTION : SPEAKER IMPEDANCE
SPK A FRONT / SPK B : 4
Ω MIN/SPEAKER
SPK A FRONT + SPK B : 8
Ω MIN/SPEAKER
CENTER, SURR, SURR-BACK : 4
Ω MIN/SPEAKER
MAIN IN
ON
OFF
SWITCHED
230V
~
50Hz
AC OUTLET
230V
~
50Hz
120W 0.5A MAX
T 773 (C) EUROPEAN VERSION
2
1
17 91011
16 15
19
83 4 5 76
18
121314
CENTER
RL
AUDIOVIDEOS-VIDEO
RL
CD
MS OUT
POWER
FRONT PANEL
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
10. RS-232
11. 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)
11. VIDEO & AUDIO
12. TAPE MONITOR
13. DIGITALAUDIO SELECTOR
14. EXT. 7.1
15. SURROUND MODE
16. LEVELS
17. TONE CONTROLS
18. TONE DEFEAT
19. SPEAKERS A & 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

8
WIRING DIAGRAM

9
ITEM PART NO. DESCRIPTION REMARK
1 276-041823-05 CABLE ASSY 4 WAYS AWG=18 3.96P A1 BD-J505B
UL1007 L=280mm
2 276-041823-11 CABLE ASSY 4 WAYS AWG=18 3.96P A1 BD-J581B
UL1007 L=420mm YB03053103-03A
3 276-062613-22 CABLE ASSY 6 WAYS AWG=26 2.5P A1 BD-J503A
UL1007 L=320mm
4 276-031823-06 CABLE ASSY 3 WAYS AWG=18 3.96P A2 BD-J509B
UL1007 L=180mm
5 276-041823-02 CABLE ASSY 4 WAYS AWG=18 3.96P A2 BD-J781B
UL1007 L=200mm REV.B
6 276-042613-08 CABLE ASSY 4 WAYS AWG=26 2.5P AU BD-J3103A
L=450mm YB03091104-02
7 276-022613-07 CABLE ASSY 2 WAYS AWG=26 2.5P DG BD-J1009A
UL1533 L=540mm
8 276-042613-06 CABLE ASSY 4 WAYS AWG=26 2.5P DG BD-J1010A
UL2468 L=540mm
9 276-042613-10 CABLE ASSY 4 WAYS AWG=26 2.5P DG BD-J901A
UL2877 L=430mm
10 276-011843-01 CABLE ASSY 1 WAY AWG18 UL1007 BLACK KE BD-J201
L=100mm W/ RING TERMINAL
11 276-052613-08 CABLE ASSY 5 WAYS #26 2.5P UL1007 L=160mm LED BD-J204A
12 276-011843-03 CABLE ASSY 1 WAY AWG=18 UL1007 BLACK MAIN BD-J701
L=360mm W/ RING TERMINAL
13 276-032613-18 CABLE ASSY 3 WAYS AWG=26 2.5P L=110mm MAIN BD-J6106B
14 276-032613-19 CABLE ASSY 3 WAYS AWG=26 2.5P L=60mm MAIN BD-J6105B
15 276-032613-29 CABLE ASSY 3 WAYS AWG26X2C UL2547 MAIN BD-J715A
L=210mm (UL LABEL)
16 276-082613-22 CABLE ASSY 8 WAYS AWG=26X3C L=480mm MAIN BD-J709A
17 276-102613-11 CABLE ASSY 10 WAYS AWG=26 2.5P UL1007 MAIN BD-J350B
L=260mm (UL LABEL)
18 276-122613-12 CABLE ASSY 12 WAYS AWG=26 2.5P L=300mm MAIN BD-J502B
19 276-142613-02 CABLE ASSY 14 WAYS #26 2.5P UL1007 L=540mm MAIN BD-J8101B
20 276-031823-11 CABLE ASSY 3 WAYS AWG=18 3.96P UL1015 SPK BD-J582B1 /
L=350mm B2/B3
21 276-041823-10 CABLE ASSY 4 WAYS AWG=18 3.96P UL1007 SPK BD-J782B1 /
L=320mm B2/B3/B4
22 276-051823-07 CABLE ASSY 5 WAYS AWG=18 3.96P UL1007 SPK BD-J501B1 /
L=250mm (V/BL/Y) B3/B5
23 276-051823-10 CABLE ASSY 5 WAYS AWG=18 3.96P UL 1007 SPK BD-J801B1 /
L=120mm (R/BK/BR/BK/O) B2/B3/B4/B5
24 276-051823-11 CABLE ASSY 5 WAYS AWG=18 3.96P UL1007 SPK BD-J504B1 /
L=320 (BK/W/BL) B2/B5
25 276-062613-09 CABLE ASSY 6 WAYS AWG=26 2.5P UL 1533X1C PO BD-J611A
L=540mm REV.B
26 276-082613-09 CABLE ASSY 8 WAYS AWG=26 2.5P UL1533 PO BD-J612A
L=340mm YB03053103-02A
27 276-042613-07 CABLE ASSY 4 WAYS AWG=26 2.5P UL2468 PS BD-J753A
L=400mm
28 276-011643-59 CABLE ASSY 1 WAY AWG=16 UL1672 BROWN PW BD-J756B
L=120mm YB04072905-02
29 276-011643-60 CABLE ASSY 1 WAY AWG=16 UL1672 BLUE PW BD-J757B
L=120mm YB04072905-01
30 276-022613-05 CABLE ASSY 2 WAYS AWG=26 2.5P UL2468 ISC S BD-J811B
L=340mm
31 276-022613-06 CABLE ASSY 2 WAYS AWG=26 2.5P UL2468 ISC F BD-J511B
L=440mm
32 276-021823-02 CABLE ASSY 2 WAYS AWG=18 UL1007 SE BD-J8105B,
L=170MM S0436-03-02 J8205B

10
ITEM PART NO. DESCRIPTION REMARK
33 276-061823-00 CABLE ASSY 6 WAYS AWG=18 UL1007 SE BD-J8202B
L=140MM S0436-03-03
34 276-061823-02 CABLE ASSY 6 WAYS AWG=18 UL1007 SE BD-J8102B
L=170MM S0436-03-01
35 276-082613-20 CABLE ASSY 8 WAYS AWG=26 2.5P UL1007 SV BD-J414A
L=380mm
36 276-011843-01 CABLE ASSY 1 WAY AWG18 UL1007 BLACK V6 BD-P4401,
L=100mm W/ RING TERMINAL P4402
37 238-172820-03 FFC CABLE 17 PINS P1.25 L=200mm W/ SHIELD J720C
38 238-200016-00 FFC CABLE 20 PINS P1.25 L=160mm W/ SHIELD J604C
39 238-280017-00 FFC CABLE 28 PINS P1.25 L=170mm W/ SHIELD J602C,J603C
40 238-300222-00 FFC CABLE 30 PINS P1.25 L=220mm W/ SHIELD J713C,J714C
41 238-302807-00 FFC CABEL 30 PINS P1.25 L=70mm J601C
42 276-011643-23 CABLE ASSY 1 WAY AWG=16 UL 1015 GREEN/ CHASIS GND,
YELLOW L=100mm AC OUTLET GND
43 276-011643-29 CABLE ASSY 1 WAY AWG=16 UL1672 BROWN J761_L, J759
L=100mm
44 276-011643-69 CABLE ASSY 1 WAY AWG=16 UL1672 BLUE J761_N, J758
L=100mm

11
BLOCK DIAGRAM

1
2
S
PE
C
IAL FUN
C
TI
O
N
FEA
TURE
AA
KEY
S
PRE
SS
O
N FR
O
NT P
ANEL
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
COLOUR BAR GENERATOR AUDIO + DIGITAL AUDIO
(VC-version units only) (all monitor outputs will show the generated colour bar)
D
ETAIL
S
&
WAVEF
O
RM
S
O
N
S
Y
S
TEM TE
S
T
&
DEB
UGG
IN
G
T
89
C
51RD2 (U202) main clock is at 20MHz (X202
)
T
89
C
51RD2 (U201) main clock is at 20MHz (X201
)
U
PPER - +5V supply to KEYB
O
ARD when power up
LO
WER - RE
S
ET line (T
C
M810LENB713) when
po
w
er
u
p
U
PPER -
O
UTPUT ENABLE (pin 24) of EPR
OM
(
W27
C
02) when changing
S
URR
O
UND M
O
DE
S
LO
WER -
C
HIP ENABLE (pin 22) of EPR
OM
(
W27
C
02) when changing
S
URR
O
UND M
O
DE
S
SC
LK (pin 43 of
CS
49326
)
L
R
C
LK (pin 42 of
CS
49326)
MC
LK (pin 30 of
CS
49326
)
N
O
TE: The wave
f
orms are based on so
f
tware version V
2
.
1
3
V
.

13
R522 R545 R571 R835
P501 P502 P503
R835 R836 R897
P802P801
P803
J511B
J811B
AMPLIFIER ADJUSTMENT
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.
ADJUSTMENT POINT DIAGRAM
FRONT/CENTER AMPLIFIER BOARD
SURROUND AMPLIFIER BOARD
ISC FRONT AMP BOARD ISC SURROUND AMP BOARD

14a
COMPONENT VIDEO BOARD
DIGITAL BOARD
PCB LAYOUT
AUDIO BOARD

14b
COMPONENT VIDEO BOARD - COMPONENT SIDE
COMPONENT VIDEO BOARD - COPPER SIDE

14c
COMPONENT VIDEO BOARD revision 3 - COMPONENT SIDE
COMPONENT VIDEO BOARD revision 3 - COPPER SIDE

15
DSP BOARD - COPPER SIDE
DSP BOARD - COMPONENT SIDE

16
FRONT/CENTER AMPLIFIER BOARD

17
SURROUND AMPLIFIER BOARD

18
KEY BOARD / LED BOARD
- COMPONENT SIDE
KEY BOARD / LED BOARD
- COPPER SIDE