NAD T744 Service Manual
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NAD T744 Service Manual

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DRAFT DATE: 08 MAY 2007
NAD
T 744
A/V Receiver

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Summary of Contents for NAD T744

  • Page 1 DRAFT DATE: 08 MAY 2007 T 744 A/V Receiver...
  • Page 2 SAFETY INFORMATION...

  • Page 3: Table Of Contents

    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 F751*AH 20-001-0075-90 FUSE TIME-LAG 7A 250V 5 X 20mm SIC UL/CSA (RoHS) F752*AH 20-001-0076-90 FUSE 1.6A 250V TIME LAG LBC 5x20mm...

  • Page 4: Specifications

    SPECIFICATIONS POWER AMPLIFIER SECTION ≤ 0.1 % 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) 260 ± ± ± ± ± 20mV Input Sensitivity (ref.

  • Page 5: Specifications

    DTS SECTION 2.5 ± ± ± ± ± 0.2 W Output Level (Vol 0 dB) : FL/FR/C/SL/SR Track 6 1 kHz ± ± ± ± ± 1.0 dB Channel Difference (FL ref) : FL/FR/C/SL/SR Track 6 1 kHz ≤ ≤ ≤ ≤ ≤ 0.08 % Harmonic Distortion (Audio Filter) : FL/FR/C/SL/SR Track 10-14 1 kHz...

  • Page 6: Rear Panel / Front Panel View

    REAR PANEL / FRONT PANEL VIEW REAR PANEL FM & AM ANTENNA AC POWER CORD MONITOR OUT 10. POWER SWITCH CD INPUT SWITCHED AC OUTLETS DIGITAL AUDIO INPUT & 12. SPEAKERS A & B DIGITAL AUDIO OUTPUT 13. DVD, SAT, VCR, VIDEO 4 & VIDEO 5 SOFT CLIPPING ON/OFF 14.

  • Page 7: Disassembly Instructions

    DISASSEMBLY INSTRUCTIONS Remove machine screws M4.0 x 8.0 (1 to 6) from the side panels. Remove tapping screw 3.0 x 8.0 (7 to 10) from the back panel. Refer to Figure No. 1. Figure No. 1 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.

  • Page 8: Wiring Diagram

    WIRING DIAGRAM FROM TRANSFORMER J753_N J753_L...

  • Page 9: Wiring Diagram Parts List

    WIRING DIAGRAM PARTS LIST Item Database Part Number Description Remark 17-012-2959-90 CABLE ASSY 3 WAYS AWG=18 3.96P UL1007 AMP1 L=180mm BD-J504A 17-012-2969-90 CABLE ASSY 5 WAYS P3.96 AWG18 UL1007 AMP1 L=200mm BD-J501A 17-012-2976-90 CABLE ASSY 12 WAYS AWG=26 2.5P UL2877 AMP1 L=120mm BD-J503A...
  • Page 10 Item Database Part Number Description Remark 17-010-0033-90 FFC CABLE 17 PINS P1.25 L=200mm J720C W/ SHIELD 17-010-0069-90 FFC CABLE 20 PINS P1.25 L=120mm J604C W/ SHIELD 17-010-0035-90 FFC CABLE 20 PINS P1.25 L=200mm J713C W/ SHIELD 17-010-0036-90 FFC CABLE 28 PIN P1.25 L=160mm J602C,J603C W/ SHIELD 17-010-0037-90...

  • Page 11: Block Diagram

    BLOCK DIAGRAM...

  • Page 12: Special Function

    SPECIAL FUNCTION 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 6 + MEMORY VFD ALL DISPLAY VIDEO 6 + TONE DEFEAT AM FREQ.

  • Page 13: Adjustment Points Diagram / Amplifier Adjustment

    ADJUSTMENT POINT DIAGRAM FRONT/CENTER AMPLIFIER BOARD R522 R545 R571 P501 P502 P503 SURROUND AMPLIFIER BOARD R835 R836 P801 P802 AMPLIFIER ADJUSTMENT Idle Current Rotate R522 fully clockwise. Connect DC millivoltmeter to P501 (i.e. Across half of R523, 0.22 Ohm resistor). Turn on the unit.

  • Page 14: Pcb Layout

    PCB LAYOUT AUDIO BOARD POWER SUPPLY (STANDBY) / POWER SWITCH...
  • Page 15 COMPOSITE VIDEO BOARD - COMPONENT SIDE COMPOSITE VIDEO BOARD - COPPER SIDE...
  • Page 16 COMPONENT VIDEO BOARD - COMPONENT SIDE COMPONENT VIDEO BOARD - COPPER SIDE DIGITAL BOARD - COMPONENT SIDE DIGITAL BOARD - COPPER SIDE...
  • Page 17 DSP BOARD - COMPONENT SIDE DSP BOARD - COPPER SIDE...
  • Page 18 FRONT / CENTER AMPLIFIER BOARD...
  • Page 19 SURROUND AMPLIFIER BOARD...
  • Page 20 KEYBOARD - COMPONENT SIDE - COPPER SIDE...
  • Page 21 MAIN BOARD...
  • Page 22 MULTI-CHANNEL BOARD - COMPONENT SIDE - COPPER SIDE...
  • Page 23 PRE-OUT BOARD - COMPONENT SIDE - COPPER SIDE...
  • Page 24 VIDEO 6 BOARD LED BOARD TRIGGER BOARD SPEAKER TERMINAL BOARD POWER SUPPLY (SECONDARY)
  • Page 25 S-VIDEO BOARD - COMPONENT SIDE S-VIDEO BOARD - COPPER SIDE...

  • Page 26: Schematic Diagram

    SCHEMATIC DIAGRAM AUDIO SWITCH...
  • Page 27 COMPONENT VIDEO...
  • Page 28 COMPOSITE VIDEO...
  • Page 29 POWER SUPPLY (SECONDARY)
  • Page 30 POWER SUPPLY (STAND BY)
  • Page 31 TRIGGER...
  • Page 32 VIDEO 6...
  • Page 33 S-VIDEO...
  • Page 34 FRONT / CENTER AMPLIFIER...
  • Page 35 SURROUND AMPLIFIER NOTE: 1. RESISTORS, UNLESS OTHERWISE SPECIFIED, ARE 1/6W, 5%. 2. ALL CERAMIC CAPACITORS, UNLESS OTHERWISE SPECIFIED, ARE 50V, 10%. 3. COMPONENTS MARKED ARE SAFETY CRITIAL PARTS. RESISTORS : RN-CERAMIC CASE, MO-METAL OXIDE, UNLESS OTHERWISE SPECIFIED ARE CARBON FILM.
  • Page 36 SPEAKER A & B RS-232...
  • Page 37 DIGITAL IN & OUT...
  • Page 38 MAIN BOARD NOTE: 1. RESISTORS, UNLESS OTHERWISE SPECIFIED, ARE 1/6W, 5%. 2. ALL CERAMIC CAPACITORS, UNLESS OTHERWISE SPECIFIED, ARE 50V, 10%.
  • Page 39 PRE-OUT NOTE: 1. RESISTORS, UNLESS OTHERWISE SPECIFIED, ARE 1/6W, 5%. 2. ALL CERAMIC CAPACITORS, UNLESS OTHERWISE SPECIFIED, ARE 50V, 10%.
  • Page 40 NOTE: 1. RESISTORS, UNLESS OTHERWISE SPECIFIED, ARE 1/6W, 5%. 2. ALL CERAMIC CAPACITORS, UNLESS OTHERWISE SPECIFIED, ARE 50V, 10%.
  • Page 41 KEYBOARD NOTE: 1. RESISTORS, UNLESS OTHERWISE SPECIFIED, ARE 1/6W, 5%. 2. ALL CERAMIC CAPACITORS, UNLESS OTHERWISE SPECIFIED, ARE 50V, 5%.
  • Page 42 MULTI-CH RESISTORS : UNLESS OTHERWISE SPECIFIED ARE CARBON FILM. NOTE: 1. RESISTORS, UNLESS OTHERWISE SPECIFIED, ARE 1/6W, 5%. 2. ALL CERAMIC CAPACITORS, UNLESS OTHERWISE SPECIFIED, ARE 50V, 10%.

  • Page 43: Ic Block Diagram

    IC BLOCK DIAGRAM 74LVC245 74LVQ574 DSP BOARD: U1002, U1003, U1014 DSP BOARD: U1008, U1009 74VHC245 KEYBOARD: U209 (11) (19) (18) (17) (16) (15) (14) (13) (12) W27C020 NJM4560 DSP BOARD: U1007 DSP BOARD: U1011~U1013, U1023 & U1025 MULTI-CHANNEL: U604, U605 PRE-OUT BOARD: U609, U610, U612,U614, U615 OUTPUT CONTROL...
  • Page 44 CS49326 DSP BOARD: U1001 74HC157 DSP BOARD: U1004 74HC157 74HCU04 DSP BOARD: U1004 DIGITAL BOARD: U1201 & U1202 COMPONENT VIDEO: U4304 SELECT STROBE...
  • Page 45 74HC251 PIN7 STROBE DIGITAL BOARD: U1203 PIN4 D0 W PIN6 PIN3 D1 PIN2 D2 PIN1 D3 PIN15 D4 PIN14 D5 PIN13 D6 Y PIN5 PIN12 D7 PIN11 A PIN10 B PIN8 GND PIN9 C PIN16 VCC AT24C16 M24Cxx KEYBOARD: U210 16Kb /8Kb /4Kb...
  • Page 46 HCF4094B KEYBOARD: U204~U207 SERIAL SERIAL CLOCK SERIAL STROBE LATCH LATCH STAGES 3 - 7 LATCH 1 OUTPUT ENABLE V DD 3-STATE STATE STATE V SS V DD V SS PT6306 KEYBOARD: U203 LATB HVO1 RDIO RDIO RDIN RDOUT LDIO LDIO DIRECTION LDIN CONTROL...
  • Page 47 T89C51RD2 KEYBOARD: U201 XTAL1 Flash XRAM EEPROM EUART XTAL2 64Kx8 Timer2 256x8 1Kx8 2Kx8 ALE/ PROG CORE IB-bus PSEN Timer 0 Parallel I/O Ports & Ext. Bus Watch Timer 1 Ctrl Port 4 Port 5 Port 0 Port 1 Port 2 Port 3 (3) (3) (3) (3) AT89C51RB2...
  • Page 48 74HC4052 74HC00 COMPONENT VIDEO BOARD: U4302 & U4303 COMPONENT VIDEO BOARD: U4304 M74HC00 74HC4052 Y CHANNELS IN/OUT X CHANNELS IN/OUT COM "Y" OUT/IN COM "X" OUT/IN Y CHANNELS IN/OUT X CHANNELS IN/OUT LC74763 S-VIDEO BOARD: U4101...
  • Page 49 M61516FP MULTI-CHANNEL BOARD: U601...

  • Page 50: Exploded View

    EXPLODED VIEW...

  • Page 51: Exploded View Parts List

    Description 08-002-0042-00 FAN DC 80 X 80 X 25 12V 0.15A 2700rpm DF128025BB W/360mm 10-005-0187-90 XFORMER PW EI-96 115V/230V T744 T96-0313002-21 ISSUE 6 POWER SWITCH TV-8 10A/250VAC UL/CSA/VDE/F/D/S PS3- 11-001-0061-90 22SPA-P7CZ BABY BLUE HN POWER CORD UL/CSA 125V VDE LF L=6'7" LP-5W NISPT-2 17-004-0009-90 AWG18 2C 2T [FOR 120V VER.]...
  • Page 52 SIDE CAP L T744 (GRAPHITE) R.2 [FOR GREY VER.] 25-022-1222-90 SIDE CAP L T744 (PAINTED TITANIUM) R.1 [FOR TITANIUM 25-022-1222-92 SIDE CAP L T744 (NEW TITANIUM) R.2 [FOR TITANIUM VER.] 25-022-1221-90 SIDE CAP R T744 (GREY) R.1 [FOR GREY VER.] 25-022-1221-92 SIDE CAP R T744 (GRAPHITE) R.2 [FOR GREY VER.]...
  • Page 53 Item Database Part Number Description 21-002-0154-90 POWER BUTTON BEZEL (GREY) R.1 [FOR GREY VER.] 21-002-0154-92 POWER BUTTON BEZEL (GRAPHITE) R.2 [FOR GREY VER.] POWER BUTTON BEZEL (PAINTED TITANIUM) R.1 [FOR 21-002-0163-90 TITANIUM VER.] 21-002-0163-92 POWER BUTTON BEZEL (NEW TITANIUM) R.2 [FOR TITANIUM 25-008-0403-90 LED LENS ROUND 25-024-0315-90...

  • Page 54: Electrical Parts List

    ELECTRICAL PARTS LIST Reference No. Database Part No. Description POWER AMP MODULE 50-940-0744-90 T744 POWER AMP MODULE FRONT & CENTER AMP BOARD PCB ASSEMBLY 27-909-0744-90 T744AH (US) Front and Center Amp Board REGULATOR U501 01-004-0049-00 IC VOLT REG 12V 1A TO-220 NJM7812 ISOWATT RESISTORS RES RN 0.22 OHM 5% 5W SIL STRAIGHT LEADS 3...
  • Page 55 Reference No. Database Part No. Description THERMISTOR THERMISTOR PTC 100 OHM M504 20-004-0039-00 PTH9MO4BH471TS2F333 THERMAL PROTECTOR M505 20-004-0043-90 THERMAL CUT OFF SWITCH 90C ST-22 DIODES D501-D503,D505-D507,D509-D511, 04-001-0001-00 DIODE SW 4NS DO35 1N4148 D521,D524-D528, D531-D536 D529,D530 04-002-0046-90 DIODE ZENER BZX55 22V 1/2W 5% DO-35 BZX-C22 SURROUND AMP BOARD PCB ASSEMBLY 27-910-0744-90...
  • Page 56 Reference No. Database Part No. Description DIODES D522,D523,D801-D806,D809,D821- 04-001-0001-00 DIODE SW 4NS DO35 1N4148 D824 AUDIO BOARD PCB ASSEMBLY 27-919-0744-90 T744AH (US) Audio Board Assembly CAPACITORS CAP ELEC SS 10uF 16V 20% 85C RAD HEIGHT C317-C319,C320-C329,C331 03-002-0129-00 =7mm MAX JACKS M303 15-003-0027-90 RCA JACK 4 R-R/W-W PCB MOUNT GOLD...
  • Page 57 Reference No. Database Part No. Description SLIDE SWITCH 11-002-0042-90 SW SLIDE 2P2T RIGHT L=9 RCA JACKS J1001,J1002,J1003,J1004 15-003-0021-90 RCA JACK 1 BLACK PCB MOUNT GOLD SMD ICS U1203 01-012-0061-00 IC LOGIC 8-CHANNEL MULTIPLEXER SOP U1201,U1202 01-012-0066-00 IC LOGIC HEX INVERTER SMD SOP 74HCU04D SMD CAPACITORS C1236-C1238 03-009-0075-00...
  • Page 58 Reference No. Database Part No. Description IC 24BIT 96KHz SURROUND SOUND CODE SSOP U1021 01-027-0002-90 CS4228AKS IC 96KHz DIGITAL AUDIO INTERFACE RECEIVER U1005 01-027-0003-90 SMD CS8415A-CSZ SMD RESISTORS R1151 02-007-0042-00 RES SMD 1K OHM 5% 1/16W 0603 R1090,R1091 02-007-0135-00 RES SMD 2.7K OHM 5% 1/16W 0603 R1115 02-007-0141-00 RES SMD 100 OHM 5% 1/16W 0603...
  • Page 59 Reference No. Database Part No. Description KEY BOARD AND LED BOARD T744 KEYBOARD AND LED ASSEMBLY 50-951-0744-90 PCB ASSEMBLY KEY BOARD PCB ASSEMBLY 27-922-0744-90 T744AH (US) Keyboard Board Assembly CAPACITORS C212 03-002-0135-00 CAP ELEC GS 1000uF 10V 20% 85C RAD ST5...
  • Page 60 Reference No. Database Part No. Description SMD RESISTORS R234 02-007-0042-00 RES SMD 1K OHM 5% 1/16W 0603 R208 02-007-0089-00 RES SMD 0 OHM +/-5% 1/10W 0805 R216 02-007-0094-00 RES SMD 1K OHM 1% 1/4W 1206 R238 02-007-0132-00 RES SMD 12K OHM 5% 1/16W 0603 R220,R256-R259,R261,R263- 02-007-0139-00 RES SMD 4.7K OHM 5% 1/16W 0603...
  • Page 61 Reference No. Database Part No. Description DIODES D701-D710 04-001-0003-00 DIODE RECT 1A/1000V DO41 WIN4007 REEL D715 04-005-0020-90 DIODE BRI 4A/70V RS402L D711 04-002-0045-90 DIODE ZENER BZX55 30V 1/2W 5% DO35 BZX55- TRANSISTORS Q701 05-001-0065-00 XTR PW NPN 1A/100V TO-126 2SD600KE REGULATORS U705,U704,U701 01-004-0048-00...
  • Page 62 Reference No. Database Part No. Description DIODES DIODE ZENER BZX55 7.5V 1/2W 5% DO35 BZX55- D602,D604 04-002-0047-90 C7.5V PRE-OUT BOARD PCB ASSEMBLY 27-924-0744-90 T744AH (US) Pre-Out Board Assembly CAPACITORS C624-C625,C640, C645,C650,C655, CAP ELEC GS 22uF 16V 20% 85C RAD HEIGHT = 03-002-0073-00 C670, C675,C693-C698 7mm MAX...
  • Page 63 Reference No. Database Part No. Description SMD CAPACITORS C747-C758 03-009-0075-00 CAP CER SMD 0.1uF 50V 20% Y5V 0603 TAPE SMD DIODES D615-D638 04-007-0039-90 DIODE ZENER SMD 12V 500mW 5% SOD123 POWER SUPPLY BOARD PCB ASSEMBLY*AH, 27-903-0744-90 PCB Assy T744AH (US) Power Supply Board PCB ASSEMBLY*C,CT 27-904-0744-90 PCB Assy T744C (CE) Power Supply Board...
  • Page 64 Reference No. Database Part No. Description SECONDARY BOARD PCB ASSEMBLY 27-926-0744-90 PCB Assy T744AH (US) Normal Secondary Board RESISTORS R781-R785 02-010-0011-00 RES MO 0.22 OHM 5% 1/2W CAPACITORS C790,C791 03-002-0149-00 CAP ELEC LP 8200uF 63V 20% 85C RAD C781-C785,C787-C788 03-004-0031-00 CAP MPF 0.1uF 63V +/-5% MEM DIODES D781...
  • Page 65 Reference No. Database Part No. Description C4146,C4136 03-004-0049-00 CAP MpF 0.47uF 63V +/-5% DMF 5 SERIES C4175 03-004-0117-00 CAP MPF 0.047uF 100V +/-5% MEM CAP TRIMMER 20pF 20% SEALED HORI. C4138 03-011-0001-00 PITCH=5mm CVN620 TRANSISTORS Q4132 05-001-0072-00 TRANSISTOR SS NPN HEF 100 200MHz TO-92 TRANSISTOR SS NPN HFE 68 30MHz SPT Q4122,Q4131 05-001-0073-00...
  • Page 66 Reference No. Database Part No. Description PHONE JACKS M351,M352,M353,M354,M355,M357 15-002-0028-90 PHONE JACK 1 BLACK PCB MOUNT 3.5mm RIGHT DIODES DIODE ZENER BZX79 5.1V 1/2W 5% DO35 BZX79-C D351-D353 04-002-0040-00 5.1V VIDEO -6 BOARD PCB ASSEMBLY 27-931-0744-90 T744AH (US) Video-6 Board Assembly CAPACITORS CAP ELEC SS 100uF 16V 20% 85C RAD HEIGHT = C4401,C4402,C4403...

  • Page 67: Packing Diagram

    AM LOOP ANTENA W/STAND 15-015-0001-90 300 TO 75 OHM ANTENNA ADAPTER 24-004-1934-90 T744 OWNERS MANUAL GB/F/D/NL W/WEEE R.2 24-004-1935-90 T744 OWNERS MANUAL E/I/P/S W/WEEE R.2 24-004-1936-90 WARRANTY CARD (AH VERSION ONLY) 28-008-0001-90 REMOTE CONTROLLER NAD HTR-2A W/BATTERY P:V1.14 L:V1 Graphite Yellow LED 24-006-0716-90...

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