Nad T-755 Service Manual

DRAFT DATE: AUGUST 2009

NAD

SERVICE MANUAL

T 755

Surround Sound

T 755

Surround Sound Receiver

Receiver

SAFETY INFORMATION

Manufactured under license under U.S. Patent #’s: 5,451,942; 5,956,674; 5,974,380; 5,978,762; 6,226,616; 6,487,535; 7,003,467; 7,212,872 & other U.S. and worldwide patents issued & pending. DTS is a registered trademark & the DTS logos and Symbol are trademarks of DTS, Inc. © 1996-2007 DTS, Inc. All Rights Reserved.

NAD ELECTRONICS INTERNATIONAL

633 GRANITE COURT, PICKERING,ON, CANADA L1W 3K1

MODEL T755 AV SURROUND SOUND RECEIVER

POWER RATING 120V 60Hz 6A

DESIGNED & ENGINEERED IN CANADA, CUSTOM

MANUFACTURED TO NAD SPECIFICATIONS IN CHINA

NAD ELECTRONICS INTERNATIONAL

MODEL T755 AV SURROUND SOUND RECEIVER

POWER RATING 230V 50Hz 3A

DESIGNED & ENGINEERED IN CANADA, CUSTOM

MANUFACTURED TO NAD SPECIFICATIONS IN CHINA

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 Database Part Number Description

F8001*AH 20-001-0072-90 FUSE TIME-LAG 6.3A 250VAC 5X20mm TSD UL/CSA/VDE/CCC

WALTER F8001*C,CT

5X20mm TSD UL/CSA/VDE/CCC WALTER

F8002*AH 5X20mm TSD

UL/CSA/VDE/SEMKO F8002*C,CT 20-001-0069-90 FUSE TIME-LAG 800mA 250V 5x20mm TSD UL/CSA/VDE/CCC WALTER 5X20mm VDE/UL/CSA 5T

NOTE:

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

20-001-0072-90 FUSE TIME-LAG 6.3A 250VAC

20-001-0076-90 FUSE 1.6A 250V TIME LAG LBC

2. Safety check out

(Only U.S.A. model)

Parts marked with the symbol are critical with regard to the risk of ﬁre and electric shock.

CONTENTS

DESCRIPTION PAGE

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

REAR PANEL / FRONT PANEL VIEW ...................................................................................................6

DISASSEMBLY INSTRUCTIONS ...........................................................................................................7

WIRING DIAGRAM ............................................................................................................................8 - 9

BLOCK DIAGRAM.................................................................................................................................10

SPECIAL FUNCTION ..........................................................................................................................11

DETAILS & WAVEFORMS ON SYSTEM & TEST & DEBUGGING................................................11-12

ADJUSTMENT POINTS DIAGRAM / AMPLIFIER ADJUSTMENT .......................................................13

PCB LAYOUT ..................................................................................................................................14- 28

SCHEMATIC DIAGRAM ...................................................................................................................29-47

ELECTRICAL PARTS LIST ..............................................................................................................48-67

IC BLOCK DIAGRAM .......................................................................................................................68-86

EXPLODED VIEW ............................................................................................................................87-88

EXPLODED VIEW PARTS LIST ......................................................................................................89-91

SINGLE AMPLIFIER CHANNEL REPAIR KIT .................................................................................92-93

PACKING DIAGRAM .............................................................................................................................94

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) ≤ 0.1 %

Input Sensitivity (ref. 8 ohms, 1 kHz) 1 ± 0.1 V

S/N Ratio (A-wtd, 1kHz, 1 W, 8 ohm, FL/C/FR/SL/SR) ≥ - 80 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, 1 W, 1 kHz) ≥ -54 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 ≥ 64 dB A-wtd ≥ 68 dB Channel Separation (1 W, 20 kHz LPF) Track 65 997 Hz ≥ 55 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 ≥ 60 dB I/P mode : L=R : 1 kHz, Ch C ≥ 60 dB I/P mode : L=-R : 1 kHz, Ch SL/SR ≥ 60 dB THD (2.2 V in, 1 W, w/ 80 kHz LPF, 1 kHz) ≤ 0.2 %

DTS SECTION

Output Level (Vol 0 dB) : FL/FR/C/SL/SR Track 6 1 kHz 0.5 -0.2/+0.8 W Channel Difference (FL ref) : FL/FR/C/SL/SR Track 6 1 kHz 0 ± 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) ≤ 60 dBμV 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 dBμ ≤ 15 dBμv S/N Ratio (60 dB, IHF wtd) Mono ≥ 60 dB ≥ 60 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 ≥ 32 dB ≥ 32 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) ≥ 50 dB ≥ 50 dB THD (60 dBμ, L=R 75 kHz for AH, 40 kHz Dev for C) Mono ≤ 0.5 % ≤ 0.5 % Stereo ≤ 0.5 % ≤ 0.5 % 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 160 x 393 mm Net Weight 17.9 Kg (39.38 lbs) Shipping Weight 22.7 Kg (49.94 lbs)

REAR PANEL / FRONT PANEL VIEW

REAR PANEL

1. IR IN/OUT

2. +12V TRIGGER OUT

3. SOFT CLIPPING

4. FM,AM ANTENNA INPUT

5. XM MODULE INPUT(AH) DAB MODULE INOUT(C,CT)

6. MP DOCK

FRONT PANEL

7. RS-232

8. COMPONENT IN/OUT

9. AUDIO/VIDEO 1~6 IN

10. AUDIO/VIDEO 3/4 OUT

11. MONITOR(S-VIDEO,VIDEO)

12. ZONE 2

13. 7.1 CH INPUT

14. AUDIO PREOUT

15. DIGITAL AUDIO IN/OUT

16. HDMI

17. SPEAKERS A, SPEAKER B

18. AC POWER INLET

19. SWITCHED AC OUTLET

20. POWER

1. POWER BUTTON

2. STANDBY LED

3. INFO

4. AM/FM/DB

5. TUNER MODE

6. MEMORY

7. NAVIGATION AND ENTER BUTTON

8. VACUUM FLUORESCENT DISPLAY(VFD)

9. REMOTE SENSOR

10. VOLUME

11. SPEAKERS A, B

12. SOURCE

13. LISTENING MODE

14. TONE CONTROLS

15. TONE DEFEAT

16. FRONT INPUT/MP

17. PHONES

18. FRONT INPUT JACKS

19. MC/MIC INPUTS

DISASSEMBLY INSTRUCTIONS

1. Remove machine screws M4.0 x 8.0 (x 6pcs) from the side panels. Remove tapping screw 3.0 x 8.0 (x 4pcs) from the back panel. Refer to Figure No. 1.

Figure No. 1

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

Figure No. 2

WIRING DIAGRAM

WIRING DIAGRAM PARTS LIST

Item Database Part Number Description Remark

1 17-012-3379-90 CABLE ASSY 2 WAYS AWG18 3.96P UL1007 MAIN BD L=250mm(RoHS) J7004A 2 17-012-3380-90 CABLE ASSY 3 WAYS AWG18 3.96P UL1007 MAIN BD L=250mm(RoHS) J7005A 3 17-012-3382-90 CABLE ASSY 10 WAYS AWG26 2.5P UL1533 MAIN BD L=300mm(RoHS) J6005A 4 17-012-3575-90 CABLE ASSY 5 WAYS AWG18 3.96P UL1007 MAIN BD L=230mm (RoHS) J7003A 5 17-012-3579-90 CABLE ASSY 6 WAYS AWG26 2.5P UL1533 MAIN BD L=80mm (RoHS) J2006A 6 17-012-3974-90 CABLE ASSY 10WAYS AWG#26 2.5P UL1007 MAIN BD L=110mm BOTH SIDE SOLDER (RoHS) J6010A/B 7 17-012-4274-90 CABLE ASSY 12 WAYS AWG26 2.5P UL1533 MAIN BD-

2.5P L=350mm (RoHS) J4002A 8 17-012-4275-90 CABLE ASSY 8 WAYS AWG26 UL1533 2.5P MAIN BD L=140mm (RoHS) J2009A 9 17-012-3571-90 CABLE ASSY 4 WAYS AWG26 2.5P L=120mm PSU BD (RoHS) J2008B 10 17-012-3943-90 CABLE ASSY 1 WAY AWG16 UL1672 BLUE PSU BD L=140mm FASTON 4.8mm (RoHS) J8011 11 17-012-3944-90 CABLE ASSY 1 WAY AWG16 UL1672 BROWN PSU BD L=140mm FASTON 4.8mm (RoHS) J8012 12 17-012-3578-90 CABLE ASSY 3 WAYS AWG18 3.96P UL1007 SURR AMP BD L=120mm (RoHS) J5003B 13 17-012-2956-90 CABLE ASSY 1 WAY AWG18 UL1007 BLACK DSP BD L=100mm W/ RING TERMINAL J6010A 14 17-012-3971-90 CABLE ASSY 20 WAYS AWG28 UL2651 L=120mm KEY BD PCB MOUNT (RoHS) J2002B 15 17-012-2956-90 CABLE ASSY 1 WAY AWG18 UL1007 BLACK SPK BD L=100mm W/ RING TERMINAL J8001 16 17-012-3383-90 CABLE ASSY 5 WAYS AWG=18 3.96P UL1007 SPK BD L=350mm(V/B/Y/O/R)(RoHS) J7006 17 17-012-3576-90 CABLE ASSY 3 WAYS AWG18 3.96P UL1007 SPK BD L=420mm (RoHS) J5602 18 17-012-3577-90 CABLE ASSY 5 WAYS AWG18 3.96P UL1007 SPK BD L=340/380/400mm (RoHS) J5304 19 17-012-3385-90 CABLE ASSY 26 WAYS AWG28 UL2651 L=150mm TRIGGER BD PCB MOUNT(RoHS) J2007B 20 17-012-4276-90 CABLE ASSY 20 WAYS AWG28 UL2651 L=200mm COMP.VID. BD-

PCB MOUNT (RoHS) J4001B 21 17-012-3168-90 CABLE ASSY 10 WAYS AWG26 UL1007 2.5P HDMI BD L=160mm (RoHS) J4306A 22 17-012-2956-90 CABLE ASSY 1 WAY AWG18 UL1007 BLACK FRONT INPUT

L=100mm W/ RING TERMINAL BD-J9301 23 17-012-2874-90 Cable assy 1 way AWG=16 UL 1672 blue L=100mm J8017,J8019 (RoHS) 24 17-012-2875-90 CABLE ASSY 1 WAY AWG16 UL 1015 CHASSIS GND, GREEN/YELLOW L=100mm (RoHS) AC OUTLET

GND 25 17-012-3572-90 CABLE ASSY 20 WAYS AWG28 UL2651 L=80mm J2005C (RoHS) 26 17-012-3573-90 CABLE ASSY 20 WAYS AWG28 UL2651 L=130mm J2001C (RoHS) 27 17-012-3948-90 CABLE ASSY 1 WAY AWG16 UL1672 BROWN J8016,J8018 L=100mm (RoHS) 28 17-010-0165-90 FFC CABLE 17 PINS P1.25 L=80MM (RoHS) J6003C

BLOCK DIAGRAM

SPECIAL FUNCTION

Function Keys Notes

Factory Reset AH Source Down + Front/MP Factory Reset C Source UP + Front/MP Toggle IR Channel Source Down + Power Check MCU & DSP Version Source Down + Source UP Check Current Video Mode Source Down + Tone Controls MIC Test Source Down + Tone Defeat VFD Test Source Down + INFO PAL/NTSC Source Down + Memory DAB/XM Source Down + Tuner Band Must cycle power before change takes effect. 9k/10k Source UP + Tuner Band Must reselect AM before change takes effect. XM 1kHz Test Tone Tuner Band + Tuner Mode XM must be selected ﬁrst. XM Signal Strength Tuner Mode for 0.5 seconds XM must be selected ﬁrst. XM Diagnostics Mode Tuner Mode for 3 seconds XM must be selected ﬁrst. Check DAB Module Version Tuner Mode for 3 seconds DAB must be selected ﬁrst. Enter Diagnostics Mode Source Down + Enter Diagnostic Mode Down Source Down + Cursor Right Diagnostic Mode Up Source Down + Cursor Left Power Off All Zones Power Toggle or Power Off for 3 seconds

DETAILS & WAVEFORMS ON SYSTEM TEST & DEBUGGING

U1001 Pin 17 - X1001C output, 24.576MHz

U1001 Pin 70 - Clock for external memory, 100MHz

U1001 Pin 2 - Master clock (Analog), 12.288MHz

U1001 Pin 12 - Left/Right clock (Analog), 48kHz

U1001 Pin 2 - Master clock (PCM), 11.2896MHz

U1001 Pin 12 - Left/Right clock (PCM), 44.1kHz

U1001 Pin 9 - Serial clock (Analog), 3.072MHz

U1001 Pin 9 - Serial clock (PCM), 2.8224MHz

U2001 Pin 12 - X2001A output, 20.000MHz

U4507 Pin 75 - X4501 output, 14.31818MHz

U4520 Pin 7 - X4503 output, 13.500MHz

ADJUSTMENT POINT DIAGRAM

LEFT/RIGHT CHANNEL AMPLIFIER BOARD

AMPLIFIER ADJUSTMENT

Idle Current

1. Rotate R5018 fully anti-clockwise.

2. Connect DC millivoltmeter to P5001.

3. Turn on the unit.

4. Adjust R5018 for 2mV +/- 0.2mV 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 P5001 R5018 FR P5101 R5118 C P5201 R5218 SL P5401 R5418 SR P5501 R5518

ISC Adjustment

A. Rotate R5634 fully clockwise. B. Use 500mV, 1kHZ sine wave, EXT7.1 input, 8ohm loading to all channels. C. Increase the output power of each channels to 80W(25.3V). D. Note the THD readings should be larger than 0.2%. E. Rotate R5624 anti-clockwise slowly until the THD readings is below 0.1%.