NAD T753 User manual

NAD
SERVICE MANUAL
T 753
T 753
Surround Sound Receiver
(
Surround Sound Receiver
DRAFT DATE: 9 MAR 2006
PHASE II

2
SAFETY INFORMATION
AH VERSION
C VERSION

3
SERVICESAFETYPRECAUTIONS
1. Replacing the fuses
CAUTION:
FOR CONTINUED PROTECTIONAGAINST THE RISK OF FIRE REPLACE ONLY WITH SAME TYPE OF
FUSE.
ReferenceDesignator Database Part Number Description
F751*AH,AHT 370-019100-00(2) FUSE TIME-LAG 10A/250VAC 5X20mm
UL/CSA 5T
F751*C,CT 370-015100-03(3) FUSE 800mA 250V TIME LAG LBC
5x20mm 5T UL/CSA/VDE/SEMKO
F752*AH,AHT 370-011100-06(4) FUSE 1.6A 250V TIME LAG LBC
5x20mm 5T UL/CSA/VDE/SEMKO
F752*C,CT 370-018100-05(2) FUSE TIME-LAG 6.3A/250VAC
5X20mm VDE/UL/CSA 5T
NOTE: <*AH , *AHT> : USA, CANADIAN MODEL ONLY.
<*C, *CT > : 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
WIRINGDIAGRAM......................................................................................................................... 8 - 10
BLOCKDIAGRAM................................................................................................................................11
SPECIALFUNCTION .......................................................................................................................... 12
DETAILS & WAVEFORMS ON SYSTEM & TEST & DEBUGGING .................................................... 12
ADJUSTMENT POINTS DIAGRAM /AMPLIFIERADJUSTMENT ...................................................... 13
PCB LAYOUT ............................................................................................................................... 14 - 29
SCHEMATIC DIAGRAM ............................................................................................................... 30 - 46
ICBLOCK DIAGRAM ................................................................................................................... 47 - 54
EXPLODEDVIEW............................................................................................................................... 55
EXPLODED VIEW PARTS LIST................................................................................................... 56 - 58
ELECTRICALPARTS LIST .......................................................................................................... 59 - 77
PACKING DIAGRAM .......................................................................................................................... 78
VERSIONHISTORY .......................................................................................................................... 79
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) 127 ±±
±±
±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 (31 for O/P 1 W, Track 35) CCIR / ARM ≥≥
≥≥
≥65 dB
Audio LPF ≥≥
≥≥
≥70 dB
A-wtd ≥≥
≥≥
≥70 dB
Channel Separation (1 W, 20 kHz LPF) 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 Hz 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
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 dBµµ
µµ
µV
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 dBµµ
µµ
µ, 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 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 170 x 423 mm
Net Weight 20.50 Kg (45.10 lbs)
Shipping Weight 24.0 Kg (52.80 lbs)

6
12 3456789
21
10
20 1119 12 13 14 15 16 17 18
FRONT PANEL
REAR PANEL / FRONT PANEL VIEW
REAR PANEL
1. FM &AMANTENNA
2. SOFTCLIPPING ON/OFF
3. MONITOR OUT
4. CD INPUT
5. IR INPUT & OUTPUT
6. +12V TRIGGER INPUT & OUTPUT
7. COMPONENT VIDEO IN &
COMPONENT VIDEO OUT
8. DIGITALAUDIO INPUT &
DIGITALAUDIO OUTPUT
9. POWER SWITCH
10. SWITCHEDAC OUTLETS
11. AC POWER INLET
12. SPEAKERSA& B
13. DVD, SAT, VCR, VIDEO 4 & VIDEO 5
14. MAIN IN /AUDIO PRE-OUTS /
SUBWOOFER OUT
15. TAPE INPUT & OUTPUT
16. MS OUT (MULTISOURCE OUT)
17. 7.1 CH. INPUTS
1. STANDBY SWITCH
2. STANDBY LED
3. AM / FM
4. FM MUTE / MODE
5. DISPLAY
6. MEMORY
7. PRESET DOWN / UP
8. SEARCH DOWN / UP
9. VFL DISPLAY
10. VOLUME (SETUP)
11. SOURCE DOWN / UP
12. SURROUND MODE
13. LEVELS
14. TONE DEFEAT
15. TONE CONTROLS
16. SPEAKERSA& B
17. VIDEO 6 INPUT
18. PHONES

7
DISASSEMBLYINSTRUCTIONS
1. Remove machine screws M4.0 x 8.0 (1to 6) from the side panels.
Remove tapping screw 3.0 x 8.0 (7to 10) from the back panel.
Refer to Figure No. 1.
2. Pull both sides of the TOP COVER slightly outwards 11 and tilt approx. 35 ° and then
remove in the direction as indicated by the arrow 12. Refer to Figure No. 2.
Figure No. 1
Figure No. 2

8
WIRING DIAGRAM
KEYBOARD
MAIN BOARD
TRIGGER BOARD
POWER SWITCH
BOARD
J8101B
J713A J714A
J715A
J719A
J720A
J717A
J710A
J711A
J712A
J707A
J704A
J502B
J709A
J713B J714B
J203A
J204B
J901B
J753B
VIDEO 6 INPUT BOARD
J758B
J757B
J709B
DSP BOARD
J604B J715B
J1009B J1010B
LED BOARD
PSU BOARD
COMPONENT VIDEO
DIGITAL BOARD
AUDIO BOARD
VIDEO BOARD
SPEAKER A
SPEAKER B
J1009A
J1010A
RS232 BOARD
TUNER
PRE-OUT BOARD MULTI-CHANNEL
J717B
J611A J612A
J6101B
J6101A
J719B
J6104A
J708B
J707B
J350A
J414B
J710B
J711B J712B
J414A
SECONDARY BOARD
ISC BOARD
J801A
J781A
J782A J582A
J801B
J783A1 J511B
J704B
J3103A
S-VIDEO BOARD
AMP 2 BOARD
(SURROUND AMP.)
AMP 1 BOARD
(FRONT & CENTER)
J612B
J502A J503A
M506
J511A
J581A
J781B
J503B
J611B
J801A
J901A
J753A
J754B
J751B
J504A
J501A
J757 J756
J761_N J761_L
J760
J758
J759
J203B
J803A
J3103B
J6102B J6103B
J6102A
J6103A
J201
J204A
J6106A J6105A
J350B
J6106A J6105A
J8101A
J784A
J803B
J504B1
J504B3
J582A1
J582A3 J582A5
J501B1
J501B3 J501B5
J582A1
J582A3 J582A5
J701
J782A1
J782A2 J782A3
P4402
J581B
THERM SENSNOR
THERM SENSNOR
TO MAIN BOARD
TO MAIN BOARD
TO MAIN BOARD
TO MAIN BOARD
TO MAIN BOARD
82-0426135-01-XX CABLE ASSY 4 WAYS #26
FROM TRANSFORMER
UL VERSION :
USE J758, J759
CE VERSION :
USE J760
MOUNT ON CHASSIS GND
33
34
35
36
32
37 38
39
31
15
30
29
28
27
2625
24
23
19
20
17
16
14
13
1211
10
8
9
21
7
6
5
4
3
2
1
18
22

9
WIRINGDIAGRAMPARTS LIST
Item Database Part Number Description Remark
1 276-022613-06 CABLE ASSY 2 WAYS AWG=26 2.5P UL2468 AMP1 BD-
L=440mm J511A
2 276-041823-11 CABLE ASSY 4 WAYS AWG=18 3.96P UL1007 AMP1 BD-
L=420mm YB03053103-03A J581A
3 276-062613-22 CABLE ASSY 6 WAYS AWG=26 2.5P UL1007 AMP1 BD-
L=320mm (RoHS) J503A
4 276-041823-02 CABLE ASSY 4 WAYS AWG=18 3.96P UL1007 AMP2 BD-
L=200mm REV.B (RoHS) J781B
5 276-042613-08 CABLE ASSY 4 WAYS AWG26 2.5P UL1533 AUDIO BD-
L=450MM (ROHS) J3103A
6 276-022613-07 CABLE ASSY 2 WAYS AWG=26 2.5P UL1533 DIGIT BD-
L=540mm (ROHS) J1009A
7 276-042613-06 CABLE ASSY 4 WAYS AWG=26 2.5P UL2468 DIGITAL BD-
L=540mm J1010A
8 276-011843-01 CABLE ASSY 1 WAY AWG18 UL1007 BLACK KEYBOARD-
L=100mm W/ RING TERMINAL (RoHS) J201
9 276-052613-08 CABLE ASSY 5 WAYS AWG26 2.5P UL1007 LED BD-
L=160mm (RoHS) J204A
10 276-011843-03 CABLE ASSY 1 WAY AWG=18 UL1007 BLACK MAIN BD-
L=360mm W/ RING TERMINAL J701
11 276-032613-18 CABLE ASSY 3 WAYS AWG=26 2.5P L=110mm MAIN BD-
J6106B
12 276-032613-19 CABLE ASSY 3 WAYS AWG=26 2.5P L=60mm MAIN BD-
J6105B
13 276-032613-29 CABLE ASSY 3 WAYS AWG26X2C UL2547 MAIN BD-
L=210mm (UL LABEL) (RoHS) J715A
14 276-082613-22 CABLE ASSY 8 WAYS AWG=26X3C MAIN BD-
L=480mm (RoHS) J709A
15 276-102613-14 CABLE ASSY 10 WAYS AWG26 2.5P UL1007 MABD-
L=460mm (UL LABEL) J350B
16 276-122613-16 CABLE ASSY 12 WAYS AWG26 2.5P UL2468 MABD-
L=230mm (UL LABEL) (RoHS) J502B
17 276-142613-02 CABLE ASSY 14 WAYS #26 2.5P UL1007 MA BD-
L=540mm (RoHS) J8101B
18 276-031823-09 CABLE ASSY 3 WAYS AWG=18 3.96P UL1015 SPK BD-
L=320mm J782B1,
J782B2,
J782B3
19 276-031823-11 CABLE ASSY 3 WAYS AWG=18 3.96P UL1015 SPK BD-
L=350mm J582B1,
J582B2,
J582B3
20 276-051823-07 CABLE ASSY 5 WAYS AWG=18 3.96P UL1007 SPK BD-
L=250mm (V/BL/Y) J801B1,
J801B3,
J801B5
21 276-051823-09 CABLE ASSY 5 WAYS AWG=18 3.96P UL1007 SPK BD-
L=120mm (BR/R/O) J501B1,
J501B3,
J501B5
22 276-031823-16 CABLE ASSY 3 WAYS AWG=18 3.96P UL1015 SPK BD-
L=240mm REV.C J504B1,
J504B3
23 276-062613-05 CABEL ASSY 6 WAYS AWG=26 2.5P PO BD-
UL1533X1C L=350mm (RoHS) J612A
24 276-062613-09 CABLE ASSY 6 WAYS AWG=26 2.5P PO BD-
UL 1533X1C L=540mm REV.B J611A

10
Item Database Part Number Description Remark
25 276-011643-29 CABLE ASSY 1 WAY AWG=16 UL1672 PS BD-
BROWN L=100mm J757
26 276-011643-69 CABLE ASSY 1 WAY AWG=16 UL1672 BLUE PS BD-
L=100mm J756
27 276-042613-07 CABLE ASSY 4 WAYS AWG26 2.5P UL2468 PS BD-
L=400mm (ROHS) J753A
28 276-021823-01 CABLE ASSY 2 WAYS AWG=18 UL1007 SE BD-
L=170MM D08033504A J803A
29 276-061823-09 CABLE ASSY 6 WAYS #18 3.96P UL1007 SE BD-
L=150MM (RoHS) J801A
30 276-082613-20 CABLE ASSY 8 WAYS AWG=26 2.5P UL1007 SV BD-
L=380mm (RoHS) J414A
31 276-011843-01 CABLE ASSY 1 WAY AWG18 UL1007 BLACK V6 BD-
L=100mm W/ RING TERMINAL (RoHS) P4402
32 238-030070-20 FFC CABLE 30 PINS P1.25 L=70mm J601C
W/SHIELD
33 238-172820-03 FFC CABLE 17 PINS P1.25 L=200mm J720C
W/SHIELD
34 238-200016-00 FFC CABLE 20 PINS P1.25 L=160mm J604C
W/SHIELD
35 238-280017-00 FFC CABLE 28 PINS P1.25 L=170mm J602C,J603C
W/SHIELD
36 238-300222-00 FFC CABLE 30 PINS P1.25 L=220mm J713C,J714C
W/SHIELD
37 276-011643-23 CABLE ASSY 1 WAY AWG=16 UL 1015 1-CHASSIS
GREEN/YELLOW L=100mm (RoHS) GND
38 276-011643-29 CABLE ASSY 1 WAY AWG=16 UL1672 1-INLET/
BROWN L=100mm PSU.BD (L),
J759
39 276-011643-69 CABLE ASSY 1 WAY AWG=16 UL1672 BLUE 1-INLET/
L=100mm PSU.BD,J758

11
BLOCKDIAGRAM

12
SPECIALFUNCTION
FEATURE KEYS PRESS ON FRONT PANEL
RESET FOR AH VERSION VIDEO 6 +SOURCE UP
RESET FOR C VERSION VIDEO 6 + SOURCE DOWN
NTSC / PAL SELECTION VIDEO + MEMORY
VFD ALL DISPLAY AUDIO 6 + TONE DEFEAT
AM FREQ. STEP AM/FM + FM MUTE
DETAILS & WAVEFORMS ON SYSTEM TEST & DEBUGGING
M6759(U202) main clock is at 20MHz(X202)
M6759(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 V2.10.

13
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 1mV reading on voltmeter.
5. Leave power on for at least 5 min, and check for idle current again.
6. Repeat for other channels.
CHANNEL JUMPER VR
FL P501 R522
FR P502 R545
C P503 R571
SL P801 R835
SR P802 R836
BS P803 R897
ISC Sensitivity
1. Connect 8 ohm loading to all channels.
2. Rotate R881 fully clockwise.
3. Load all channels at full power using 1kHz sine wave.
4. At this time, monitor the THD of the SL,SR,BS output. Clipping should occur before full power
achieved.
5. Rotate R834 counter-clockwise slowly until the THD just below 0.1%.
6. Repeat step 2-5 for R834 but monitor FL, FR & Center output.
7. The procedure is finish at this step.
8. Load all channels at full power using 1kHz sine wave with 4 ohm load.
9. The clipping power(at THD 0.1%) should less than 85W.
ADJUSTMENTPOINTDIAGRAM
R522 R545 R571
P501
P502 P503
P803
P802P801
R835 R836 R897
R881
FRONT / CENTER AMPLIFIER BOARD
SURROUND AMPLIFIER BOARD
SECONDARY / ISC BOARD

14
PCBLAYOUT
AUDIO BOARD
POWER SUPPLY (STANDBY) BOARD

15
COMPONENT VIDEO BOARD - COMPONENT SIDE
COMPONENT VIDEO BOARD - COPPER SIDE
DIGITAL BOARD - COMPONENT SIDE SIDE
DIGITAL BOARD - COPPER SIDE

16
DSP BOARD - COPPER SIDE
DSP BOARD - COMPONENT SIDE

17
FRONT / CENTER AMPLIFIER BOARD - COMPONENT SIDE

18
FRONT / CENTER AMPLIFIER BOARD - COPPER SIDE

19
SURROUND AMPLIFIER BOARD - COMPONENT SIDE

20
SURROUND AMPLIFIER BOARD - COPPER SIDE