NAD C 426 Service Manual
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NAD C 426 Service Manual

Stereo am/fm tuner
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NAD
C 426
S T E R E O
AM/FM TUNER

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Summary of Contents for NAD C 426

  • Page 1 C 426 S T E R E O AM/FM TUNER...

  • Page 2: Table Of Contents

    SERVICE SAFETY PRECAUTIONS 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 the supply circuit. 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.

  • Page 3: Specifications

    SPECIFICATIONS AM BAND SPECIFICATION Frequency Range 530 - 1710 KHz Step 10 KHz 531 - 1602 KHz Step 9 KHz FREQ (KHz) UNIT LIMIT Usable sensitivity dBuV <= 30 (400Hz, -20dB, direct input) /1000 S/N RATIO >= 38 (5mV input) /1000 THD (5mV input) <= 3...
  • Page 4 Capture ratio (40dBu) < 3 AM Supression 98MHz > 60 @ 60dBu 100% mod FM, 30% mod AM Pilot suppression L & R 98 MHz > 60 Frequency response 20Hz & 10KHz 0 +/- 1.5 ( 1KHz Ref ) UL 75Us,CE50Us 10.

  • Page 5: Rear Panel / Front Panel

    REAR PANEL / FRONT PANEL REAR PANEL FM ANTENNA TERMINAL IR IN AM ANTENNA TERMINAL +12V TRIGGER IN OUTPUT (L, R) AC MAINS INPUT RS-232 FRONT PANEL STANDBY LED MEMORY STANDBY BUTTON PRESET/TUNE FM/AM REMOTE SENSOR FM MUTE/MODE 10. VFD BLEND 11.

  • Page 6: Disassembly Instructions

    DISASSEMBLY INSTRUCTIONS 1. Remove machine screws M 4.0 x 6.0 ( 1 to 4 ) from the side panels. Remove tapping screw 3.0 x 8.5 5 from the back panel. Refer to Figure No.1. Figure No.1 2. Pull both sides of the TOP COVER slightly outwards 6 and tilt approx. 35˚ and then remove in the direction as indicated by the arrow 7 .

  • Page 7: Block Diagram

    BLOCK DIAGRAM - 7 -...

  • Page 8: Wiring Diagram

    WIRING DIAGRAM 7013-0490+0 - 8 -...

  • Page 9: Adjustment Points Diagram

    ADJUSTMENT POINTS DIAGRAM - 9 -...

  • Page 10: Instrument Setup

    INSTRUMENT SETUP 1. FM MEASUREMENT ANTENNA OUTPUT Fig. 1 TERMINAL TERMINAL DISTORTION UNIT SIGNAL METER GENERATOR OUTPUT TERMINAL P901 VOLTMETER MILLIVOLT- METER OSCILLOSCOPE ANTENNA OUTPUT Fig. 2 TERMINAL TERMINAL DISTORTION UNIT STEREO SIGNAL METER GENERATOR GENERATOR OSCILLOSCOPE VOLTMETER 2. RDS MEASUREMENT ANTENNA TERMINAL Fig.

  • Page 11: Alignment Procedures

    ALIGNMENT PROCEDURES FM/RDS SECTION - FM mono: 1kHz, 75kHz devi., 60dB/μV - FM stereo: 1kHz, 67.5kHz devi., 60dB/μV Pilot signal 19kHz 7.5kHz devi. OUTPUTS - Connect the 47Kohm resistor unless otherwise noted. Stereo Step Connection FM SG Tuning Output Adjustment Adjust Item modulator...
  • Page 12 LED BOARD KEY BOARD POWER SUPPLY BOARD C110 M104 M105 M103 P/N:1726-042A+000B L103 YELLOW BLUE WHITE P/N:PCB-C426+KEY C107 J203B2 SECTION:E,ISSUE:B P/N:1726-042A+000B PCB-C426+LED KEY-SDBY C230 C109 SECTION:D,ISSUE:B LED-BLUE R105 R106 P/N:1726-042A+000B LED-ORANGE C111 D108 PCB-C426+PSU R104 LED-ORANGE SECTION:C,ISSUE:B C231 J201B D107 R103 Top side Bottom side...

  • Page 13: Pcb Layout

    PCB LAYOUT MAIN BOARD C426 D981 Top side R999 J222 J402 D903 U402 R990 J226 C412 R991 M302 J904 C410 J301B J401B C220 D401 R708 C708 R705 C215 C707 J232 D409 J708 C404 J236 C414 R706 U701 J234 M303 C413 R707 R207 R702...
  • Page 14 MAIN BOARD Bottom side - 14-...

  • Page 15: Schematic Diagram

    SCHEMATIC DIAGRAM KEY / MCU / DISPLAY R703 R702 330R 1606 M210 FM 106.2 MHz IR_IN REMOTE SENSOR U701 Q702 2SC1923 R701 C201 100u M209 R706 C709 C706 104K 100u C202 C701 C702 R705 R704 0.01u 473J R229 74HC86 SG[01:18] IR-IN D701 DAP202K...
  • Page 16 TUNER M971 NMRF-5077 L903 NMC-4085 C991 C953 M901 C973 M971-A 272J 473J MITSUMI FE450-G11 C975 C954 10U/16V 272J C965 R973 M971-C 272K C974 L904 M971-B 223Z NMC-4085 C959 C977 1003 C963 R961 P901 10U/16V 10U/16V 22U/16V 470R 1.5p SEP. 10U/16V 470p 100K R956...
  • Page 17 T101 L102 R102 100K/1W D109 F101 RL101-A D108 27uH D105 L103 1N4007 UF4006 UF4006 +3V3-SDBY D101 D103 T1A 230V only 27uH T1.6A 120V only C104 103M/400V 1N4007 1N4007 R103 C110 C109 C107 R105 100U R108 470U 103K 2K7 1/4W AC INPUT D107 M101 C101...

  • Page 18: Ic Block Diagram

    IC BLOCK DIAGRAM DSP Board U202: PT6311 SG1/KS1 SG2/KS2 Control SG3/KS3 SG4/KS4 Serial SG5/KS5 DOUT Data SG6/KS6 Interface Dispaly Memory SG7/KS7 Segment SG8/KS8 Driver SG9/KS9 Grid SG10/KS10 Driver SG11/KS11 SG12/KS12 Key Scan Timing Generator Output SG13/GR16 SG14/GR15 SG15/GR14 SG16/GR13 General SG17/GR12 Key Matrix Memory Input...

  • Page 19: Main Board

    Main Board U201: P89LCP936 P2.0/ICB/DAC0/AD03 P2.7/ICA P2.6/OCA P2.1/OCD/AD02 P0.0/CMP2/KBI0/AD01 P0.1/CIN2B/KBI1/AD10 P1.7/OCC/AD00 P0.2/CIN2A/KBI2/AD11 P1.6/OCB P0.3/CIN1B/KBI3/AD12 P1.5/RST P0.4/CIN1A/KBI4/DAC1/AD13 P0.5/CMPREF/KBI5 P89LPC935FDH P3.1/XTAL1 P89LPC936FDH P0.6/CMP1/KBI6 P3.0/XTAL2/CLKOUT P1.4/INT1 P0.7/T1/KBI7 P1.3/INT0/SDA P1.0/TXD P1.2/T0/SCL P1.1/RXD P2.2/MOSI P2.5/SPICLK P2.4/SS P2.3/MISO P89LPC933/934/935/936 ACCELERATED 2-CLOCK 80C51 CPU 4 kb/8 kB/16 kB UART CODE FLASH internal bus...
  • Page 20 Main Board Main Board U203: AT24C08A-10PU U204: MAX232D C1– DOUT1 START RIN1 STOP LOGIC C2– ROUT1 SERIAL CONTROL H.V. PUMP/TIMING V– DIN1 LOGIC LOAD DOUT2 DIN2 COMP DATA RECOVERY DEVICE RIN2 ROUT2 ADDRESS COMPARATOR LOAD DATA WORD EEPROM Main Board ADDR/COUNTER U402: NJM78M56FA Y DEC...
  • Page 21 Main Board U902: LC72723M V REF FLOUT Vddd Vdda CLOCK RECOVERY REFERENCE (57kHz) (1187.5Hz) VOLTAGE Vssd Vssa V REF 57kHz RDDA DATA MPXIN SMOOTHING ANTIALIASING (SCF) DECODER FILTER FILTER RDCL MODE (128bits) CLK(4.332MHz) RDS-ID/READY TEST RDS-ID TEST DETECT X IN X OUT Main Board U903: LC7218-E...
  • Page 22 PSU Board PDIP-7 U101: NCP1014 8 GND 7 GND 5 DRAIN (Top View) Startup Source Iref = 7.4 mA Drain Vclamp* Rsense High when V UVLO 250 ns Management L.E.B. Reset 65, 100 or EMI Jittering Flip-Flop 130 kHz Driver DCmax = 65% Clock Reset...

  • Page 23: Electrical Parts List

    ELECTRICAL PARTS LIST Location Part Number Description PCB ASSY DSP EU 1002 SVC-C42626+DSP PCB ASSY DSP EU PC BOARD 1006 1726-042A+000B PCB MAIN/KEY/DIS/PSU/LED CAPACITOR C201 157C-107M+K-IU CE 10V 100uF 20% R5 5X11 C202 150F-103K+2-DC CC 50V 0.01U 10% AT C210 150F-104K+2-FC CC 50V 0.1UF 10% AT C212...
  • Page 24 Location Part Number Description VFDA 4135-8341+0 HOLDER-VFD TINNED STEEL VFDB 4154-4881+1 CUSHION 21X8X2 PCB ASSY KEY EU 1005 SVC-C42626+KEY PCB ASSY KEY EU & CA PC BOARD 1006 1726-042A+000B PCB MAIN/KEY/DIS/PSU/LED WAFER/SOCKET J201B 2102-040R+J01 WAFER 4P P2.0 90DEG MISCELLANEOUS C230, C231 150F-103K+2-DC CC 50V 0.01U 10% AT VR201...
  • Page 25 Location Part Number Description C217 150F-223K+2-FD CC 50V 0.022uF 10% AT C219, C222 150F-104K+K-II CC 50V 0.1U 10% RLT 5x5 C223 157F-475M+K-IU CE 50V 4.7U 20% RLT 5X11 C401, C402, C403, C404 150F-223K+2-FD CC 50V 0.022uF 10% AT C405, C406 157D-228M+5-X&TU CE 16V 2200U 20% RL C407...
  • Page 26 Location Part Number Description C945 150F-101K+2-DC CC 50V 100P 10% AT C946 157F-105M+K-IUW CE 50V 1U 20% RLT 5X11 C947 150F-474M+K-II CC 50V 0.47U 20% RLT 5X5 C948 157F-105M+K-IUW CE 50V 1U 20% RLT 5X11 C949, C950 150F-223K+2-FD CC 50V 0.022uF 10% AT C951 157F-475M+K-IU CE 50V 4.7U 20% RLT 5X11...
  • Page 27 Location Part Number Description D208 4802-1000+2 DIODE SCHOTTKY 100V D401, D402, D403, D404, D405, D406, D407, D408, 4804-0010+2 DIODE W1N4001-A(WA) AT D409 D410 4837-27V0+2 DZ 1/2W 27V(26.2-27.6)AT D411, D412 4837-10D1+2 DZ 1/2W 9.94-10.44V ROHM D701 4802-02K0+3 DIODE SW 80V 300MA D903 4837-3V36+2 DZ 1/2W +-5% 3.3V TEMIC...
  • Page 28 Location Part Number Description Q901 485C-945P+K TR NPN 2SC945P Q902 4851-9230+K TR NPN 2SC1923-0 Q903 485A-114E+K TR DTA114ESA RLT ROHM Q922, Q923, Q942 4860-1590+K TR 2SC1740STPR Q943, Q944 4860-8120+G TR 2SD1468S TPS ROHM Q945 485A-114E+K TR DTA114ESA RLT ROHM Q980 485C-114E+K TR DTC114ES RLT Q981...
  • Page 29 Location Part Number Description R207, R933, R952, R953 4705-223J+C RCF 1/4W 22K 5% ATS R703 4705-303J+C RCF 1/4W 30K 5% ATS R702, R904, R909, R910 4705-331J+C RCF 1/4W 330R 5% ATS R907, R946, R949, 4705-332J+C RCF 1/4W 3.3K 5% ATS R212, R228, R908, R961, R962, R988 4705-471J+C RCF 1/4W 470R 5% ATS...
  • Page 30 Location Part Number Description L972 5600-3416+S COIL AM IFT NMIF-4062 Label 3002-0027+0 LABEL-BLANK 10X5 WHT PET M302 2113-2036+1 JACK PHONE 4P RED D315 M985 2300-1220+0 CRYSTAL 4.332MHZ M986 4131-7701+0 ANTENNA WASHER P901 2113-1160+0 WAFER 2P ST. P=2.5 NH U201A 312A-0970+01 SOFTWARE MCU C426V04 U201C 3005-5361+0...
  • Page 31 Location Part Number Description TRANSISTOR Q301 4860-8810+U TR NPN MPSA42 300V 0.5A Q302 485C-114E+K TR DTC114ES RLT RESISTOR R102 4718-104J+2 RMF 1W 100K 5% AT R103 4715-152A+2 RMF 1/4W 1.5K 1% AT R106 4711-203A+2 RMF 1/8W 20K 1% AT R108 4717-335J+2-S1 RMF 1/2W 3.3M 5% AT R301...

  • Page 32: Exploded View

    EXPLODED VIEW 15 14 13 - 32 -...

  • Page 33: Exploded View Parts List

    EXPLODED VIEW PARTS LIST ITEM PART NUMBER DESCRIPTION 2446-6205+2 VOLUME KNOB GREY 2446-6206+2 VOLUME KNOB TITANIUM 3717-6811+0 DISPLAY LENS 2954-3006+3000 SCREW B-TITE BIND M3X6 SVC-C42626+FRONT Complete fascia assembly with buttons, window, & VFD Titanium SVC-C42627+FRONT Complete fascia assembly with buttons, window, & VFD Graphite 3717-7012+0 POWER BUTTON LENS GREY 3717-7011+0...

  • Page 34: Packing Diagram

    RCA PLUG (MALE) 1497-1932+0 POLYBAG FOR REMOTE CONTROL RF CONNECTOR PLUG BALUN 2103-6101+1 Proprietary information for servicing purposes only. The information herein may not be used com- mercially without the prior written agreement of NAD Electronics International, Toronto, Canada. - 34 -...

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