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NAD C 425 Service Manual

Other manuals for C 425: Catalog, Owner's Manual, Datasheet
Manual is about: Stereo AM/FM Tuner

Summary of C 425

  • Page 1

    Nad c 425 stereo am/fm tuner c 425 stereo am /f m t un er se rv ic e m a n u al.

  • Page 2: Service Safety Precautions

    - 2 - - 3 - service safety precautions 1. 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 wit...

  • Page 3: Specifications

    - 2 - - 3 - specifications am tuner section input level is expressed as the reading in open-circuit of 75-ohm source impedance signal generator usable sensitivity (999/1000khz) ≤30dbµ s/n ratio (5mv in) ≥38db thd (5mv in) ≤3% if rejection (450khz) ≥36db image rejection (f+2xif) ≥28db selectivity ≥17...

  • Page 4: Rear Panel / Front Panel

    - 4 - - 5 - rear panel / front panel 1. Fm antenna 2. Am antenna 3. Output 4. Ir in 5. 12v trigger in 6. Ac line cord 7. Rs-232 1. Power on / off 2. Power status indicator 3. Blend 4. Memory 5. Fm mute / mode 6. Am / fm 7. Display 8. Preset / tune 9. Display area 10. Preset / tune control front pane...

  • Page 5: Disassembly Instructions

    - 4 - - 5 - 5 4 3 1 2 7 6 6 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 rem...

  • Page 6: Block Diagram

    - 6 - - 7 - am loop ant fm ant output front end env172d3g1 vfd cpu lc866448b u201 u202 vfd driver pt631 1 key ma trix trigger in u203 eeprom 24c08 pll lc72723m rds decoder u901 am/fm if la1837 muting ir in u701 74hc86 m218 remote sensor power suppl y vfd -vp +5v cpu +10v ac input l r vt vt ce data c...

  • Page 7: Wiring Diagram

    - 6 - - 7 - wiring diagram main board key board displa y board led board transformer power suppl y board yellow blue white.

  • Page 8: Adjustment Points Diagram

    - 8 - - 9 - adjustment points diagram osc rf vt.

  • Page 9: Instrument Setup

    - 8 - - 9 - fm signal generator antenna terminal output terminal distortion meter distortion meter ac voltmeter oscilloscope ac voltmeter or oscilloscope ac voltmeter or oscilloscope output terminal output terminal l r antenna terminal antenna terminal antenna terminal am loop antenna (accessory) am...

  • Page 10: Alignment Procedures

    - 10 - 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. Item step connection of instrument fm sg output stereo modulator output tuning freq...

  • Page 11

    - 11 - pcb layout power supply board display board led board key board.

  • Page 12

    - 12 - - 13 - main board.

  • Page 13

    - 12 - - 13 - schematic diagram key / mcu / display note: 1. Resistors are carbon film 5% 1/8w unless otherwise specified. 2. Ceramic capacitors are 50v 10% unless otherwise specified. 425kb-mp.Sch-1 - tue jul 18 09:17:14 2006 6.5v.

  • Page 14

    - 14 - tuner note: 1. Resistors are carbon film 5% 1/8w unless otherwise specified. 2. Ceramic capacitors are 50v 10% unless otherwise specified..

  • Page 15: Ic Block Diagram

    - 15 - serial data interface din dout clk stb vdd r osc sw1 sw2 sw3 sw4 led1 led2 led3 led4 led5 k1 k2 k3 k4 vdd gnd vee sg1/ks1 osc general input register led driver dimming circuit grid driver segment driver grid driver key scan output control dispaly memory timing generator key matrix memory sg2/...

  • Page 16

    - 16 - - 17 - main board u201: p89lcp936 accelerated 2-clock 80c51 cpu 4 kb/8 kb/16 kb code flash 256-byte data ram port 2 configurable i/os port 1 configurable i/os port 0 configurable i/os keypad interrupt programmable oscillator divider cpu clock configurable oscillator on-chip rc oscillator inte...

  • Page 17

    - 16 - - 17 - vcc 8 7 4 6 5 3 2 1 gnd wp scl load load inc data word addr/counter y dec x dec r/w comp serial control logic en h.V. Pump/timing data recovery eeprom serial mux d out /ack logic device address comparator start stop logic sda a2 a1 a0 d in d out main board u203: at24c08a-10pu main boar...

  • Page 18

    - 18 - - 19 - main board u902: lc72723m vdda 3 reference voltage antialiasing filter data decoder vref 1 vref flout 5 cin 6 pll (57khz) clock recovery (1187.5hz) + _ vddd 11 vssd 10 rdda 14 rdcl 15 mode 12 rst 13 rds-id/ready 16 vssa 4 mpxin 2 test 7 test 57khz bpf (scf) smoothing filter osc clk(4.3...

  • Page 19: Electrical Parts List

    - 18 - - 19 - electrical parts list display assy pc board pcb-c42526+dsp pcb assy display pcb 1725-859a+0000 pcb main/key/dis/psu/led capacitor c201 157b-107m+k-lii ce 6.3v 100uf 20% rlt c202 150f-103k+2-fc cc 50v 0.01uf 10% at 3.5 c210 150f-104k+2-fc cc 50v 0.1uf 10% at c211 157q-107m+k-lui ce 35v ...

  • Page 20

    - 20 - - 21 - location part number description wire j201a 7012-6688+0 conn wire 3p p=2.5 26awg miscellaneous m209 4154-2101+0 vfd holder m210 4814-3te2+3 ir sensor pic-26043te2 vfd 2460-1961+0 display-vfd hna-10sm55 key assy pc board pcb-c42526+key pcb assy key c425 pcb 1725-859a+0000 pcb main/key/d...

  • Page 21

    - 20 - - 21 - location part number description *ca pcb-c425d6+main pcb assy main pcb 1725-859a+0000 pcb main/key/dis/psu/led capacitor c203 150f-223k+2-fd cc 50v 0.022uf 10% at c204 157d-107m+k-iui ce 16v 100uf 20% rlt c205 150f-104k+k-ii cc 50v 0.1u 10% rlt 5x5 c206, c207, c208, c209 157f-105m+k-iu...

  • Page 22

    - 22 - - 23 - location part number description c926 153f-333j+k-nlm cm 50v 0.033u 5% rlt 7.5 c927 157f-225m+k-iui ce 50v 2.2u 20% rlt c928 157d-106m+k-iui ce 16v 10uf 20% rlt 5x11 c929 157f-224m+k-iui ce 50v 0.22uf 20% rlt c930 150f-223k+2-fd cc 50v 0.022uf 10% at c931 157b-107m+k-iui ce 6.3v 100uf ...

  • Page 23

    - 22 - - 23 - location part number description c991 153f-102j+k-im cm 50v 1000p 5% rlt 5x7 c992 150f-103k+2-fc cc 50v 0.01uf 10% at 3.5 c995 150f-223k+2-fd cc 50v 0.022uf 10% at c996 157d-107m+k-iui ce 16v 100uf 20% rlt diode d202, d203, d204, d205, d207, d208, d209, d309 4804-1480+2 diode 1n4148t a...

  • Page 24

    - 24 - - 25 - crystal m905 2300-0440+0 crystal 7.2mhz 20ppm m985 2300-1220+0 crystal 4.332mhz ceramic filters m902, m904 2701-0010+1 cf10.7 +-30 m903 *eu 2701-0010+1 cf10.7 +-30 m911 2701-0680+0 cf 450 +-1 transistor q401, q402 485a-950y+k tr 2sa950-y hfe100-200 q403 4860-0050+k tr ss8050 c/d rlt q7...

  • Page 25

    - 24 - - 25 - r723 4701-103j+2 rcf 1/8w 10k 5% at r901 *ca 4701-332j+2 rcf 1/8w 3.3k 5% at r901 *eu 4701-333j+2 rcf 1/8w 33k 5% at r902 4701-220j+2 rcf 1/8w 22r 5% at r903 *ca 4701-102j+2 rcf 1/8w 1k 5% at r903 *eu 4701-123j+2 rcf 1/8w 12k 5% at r904 *eu 4701-331j+2 rcf 1/8w 330r 5% at r905 *eu 4701...

  • Page 26

    - 26 - - 27 - r969 4701-104j+2 rcf 1/8w 100k 5% at r972 4701-103j+2 rcf 1/8w 10k 5% at r973 4701-183j+2 rcf 1/8w 18k 5% at r974 4701-104j+2 rcf 1/8w 100k 5% at r975 *ca 4701-243j+2 rcf 1/8w 24k 5% at r975 *eu 4701-563j+2 rcf 1/8w 56k 5% at r978 4701-105j+2 rcf 1/8w 1m 5% at r981 4701-101j+2 rcf 1/8w...

  • Page 27

    - 26 - - 27 - psu assy pc board eu pcb-c42526+psu pcb assy psu ca pcb-c425d6+psu pcb assy psu pcb 1725-859a+0000 pcb main/key/dis/psu/led capacitor c801 8910-0049+0 cap400v 4700p resistor r801 *ca 4717-335j+2-s rmf 1/2w 3.3m 5% at ul switch 0401 5200-3151+0-01 power switch miscellaneous gnd *ca 4132...

  • Page 28: Exploded View

    - 28 - - 29 - exploded view 0106 0102 01 15 0108 01 19 0126 0130 0133 01 13 0123 01 11 0132 0131 01 18 01 14 0129 0136 0100 0124 0121 01 12 0101 01 19 0109 01 16 01 10 j202 0141 0122 0137 0140 0107 0125 0127 01 17 0105.

  • Page 29: Exploded View Parts List

    - 28 - - 29 - exploded view parts list item part number description 0100 *ca 1402-351f+2 chassis ah natnc425 0100 *eu 1402-351g+2 chassis ce natnc425 0101 tita 1402-3532+0 top cover silver (c542) 0101 grey 1402-3533+0 cover-top black (c542) 0102 grey 1466-5205+3 fascia black natnc425 0102 tita 1466-...

  • Page 30

    - 30 - - 31 - note: - the components identified by mark are critical for risk of fire and electrical shock. Replace only with part number specified. - : canadian model only. - : european model only. 0136 *eu 7009-3110+0 ac cord (semko) 0137 3714-5706+0 led lens (412) clear san 0140, 0141 2954-3008+0...

  • Page 31: Packing Diagram

    - 30 - - 31 - packing diagram 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. C425 manual 10 7 2 11 5 6 1 2 4 3 8 9 12 13 14 item part no. Description q’t...

  • Page 32: Vic

    Se r vic e m a n u a l © nad 2006 c 425 stereo am/fm tuner nad electronics international toronto.