Nad-T-975-Service-Manual(1) 电路图维修手册.pdf

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1、? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? RadioFans.CN 收音机爱好者资料库 CONTENTS FRONT PANEL/REAR PANELVIEW? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?3 SPECIFICATIONS? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?

2、? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 4 ALIGNMENT PROCEDURE/ALIGNMENT POINTS? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 5-6 WIRING DIAGRAM? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?7 SCHEMATIC DIAGRAM? ?

3、? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?8-15 PCB LAYOUT? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 16-23 ELECTRICALPARTS LIST? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?

4、? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?24-37 EXPLODED VIEW? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 38 EXPLODED VIEW PARTS LIST? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?

5、 ? ? ? ? ? ? ? ? ? ?39 PACKING DIAGRAM? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?40 SERVICE SAFETY PRECAUTIONS 1. Replacing the Fuses CAUTION: FOR CONTINUED PROTECTION AGAINST THE RISK OF FIRE REPLACE ONLY WITH SAME TYPE OF FUSE.

6、REFERENCE NO.PART NUMBERDESCRIPTION Rear Panel AH20-11203-10MDAT20AL/250V C20-12103-20MDAT10AL/250V AMP Board F101/F10220-12632-00T6.3AL/250V PSU Board F201-F20420-12162-01T1.6AL/250V NOTE: *AH : North American version only *C: European version only 2. Safety-check out (North American model only) Be

7、fore 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 symbolare critical with regard to the risk of fire and electric shock.Replace only parts recommended by

8、the manufacturer. - 2 - RadioFans.CN 收音机爱好者资料库 ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? - 3 - RadioFans.CN 收音机爱好者资料库 - 4 - SPECIFICATIONS CON

9、TINUOUS AVERAGE POWER?140 W (21.5 dBW) OUTPUT INTO 8 OHMS OR 4 OHMS (Min. power per channel, 20 Hz 20 kHz, both channels driven, with no more than rated distortion) Rated Distortion?0.03% (THD 20 Hz 20 kHz) Clipping power?170 W(22.3 dBW) (maximum continuous power per channel). IHF dynamic power (Max

10、imum short term power per channel) 8 ohms:?220 W (23.4 dBW) 4 ohms:?385 W (25.9 dBW) 2 ohms:?450 W (26.5 dBW) Damping factor300 (ref. 8 ohms 50Hz) Input ImpedanceR = 1 Mohms C = 180 pF Input sensitivity (for rated output into 8 ohms)1180mV+/-50mV Voltage gain29 dB Frequency response 20 Hz 20 kHz?0.2

11、 dB - 3dB at 3 Hz/100 kHz Signal / Noise ratio, A-weighted96 dB ref. 1 W 125 dB ref. 140W DIMENSIONS AND WEIGHTS Net Weight31 kg (68.0 Ib) Shipping Weight33 kg (72 Ib) Dimension (WHD)435 180 450mm ALIGNMENT PROCEDURE (T975) A. THERMAL SENSE ADJUSTMENT This adjustment should be always done when the T

12、975 is in a cool condition. (That means the temperature inside the unit should be almost same as the ambient temperature.) Connector P208B that connects the transformer and power board should be removed to avoid the Idling current heating up the unit excessively) At ambient temperature of 25 C degre

13、es and when the unit is just turned on (still in cool condition), adjust the pot RV103 (as marked as “Thermal Sense ADJ” in below drawing) for a voltage between the THERMAL TEST POINT and AGND to be 750mV+/-10mV. If the ambient temperature is different, the voltage setting should be changed by 20mV

14、per degree C difference. So at 20C degrees, the voltage should be 850mV+/-10mV; and at 30C degrees, the voltage should be 650mV+/-10mV, etc. B. DC OFFSET VOLTAGE The DC OFFSET between OFFSET Test Point and AGND must be within 0+/-3mV. If its found to be out of this range, change the TL084BCD to one

15、selected for low offset voltage to meet the requirement. C. IDLING CURRENT The idling current in the output stage of the poweramp should be set to 40mA+/-10mA per pnp-npn transistor pair (This means the mid point voltage is 17.6mV with down limit of 13.2mV and up limit of 22mV). The alignment proced

16、ure is: At first, adjust RV102 (Marked as “Idling Current ADJ” in the drawing below) for a voltage of 17.6mV +/- 1mV between Test point 1 and 2. Then preheat the unit for 5 minutes, let idling current settled and then readjust to 17.6mV +/- 1mV. Pls note: 1.The idling current must be adjusted when a

17、ll modules are assembled into the unit. 2.Though the idling current is set as 17.6mV +/-1mV during the adjustment, due to the influence of varied ambient temperature and mains voltage etc., the idling current will drift after some time. During the normal checking of idling current in the service fie

18、ld, its acceptable as long as the voltage is in the range of 13.2mV22.0mV. D. ISC SENSITIVITY The ISC sensing voltage range is 0mV+/-50mV. But, for the alignment process during production, we tighten the limit to 0mV+/-10mV. That is to adjust Pot RV104 (as marked as “ISC SENSE ADJ” in the below draw

19、ing) to get a voltage between the “ISC SENSE TEST POINT” and AGND to be 0mV+/-10mV. (Please note the ISC should be adjusted when all modules are plugged in. Its not possible to get 0mV +/-10mV if any of the modules are removed.) E. Fan Cut Off Point Adjustment Check the Fan sense voltage first. Turn

20、 Pot RV201 (on the power supply board) to the end clockwise and confirm TP1 of J201 is negative voltage. Run the unit to heat it up and to start turning the fan. - 5 - For example; all 7 channels at 50W/4 ohms for 10 minutes or 5 minutes or even less (as long as the fan can starts turning). Turn off

21、 the signal but still keep the unit operating for 1 minute. Then run all 7 channels at 1kHz, 0.25W at 4 ohms load, monitor the voltage at TP1 J201. Adjust RV201 to get the voltage from negative to positive to ensure that the Fans are turned off. Then run all 7 channels at 1kHz, 0.5W at 4 ohms load,

22、monitor if the voltage at TP1 of J201 is negative, if not, adjust Pot RV201 just to the point that TP1 changes from positive to negative (to get the fans just start turning). Finally, turn off the signal and monitor if fans stop turning within about 30s Maximum. - 6 - AGND +62V +62V -62V -62V AGND A

23、GND AGND ISCTRIG AC OFF SEN PROTECT -68V +68V -18V +18V SC PNP SC NPN AGND +62V +62V -62V -62V AGND AGND AGND ISCTRIG AC OFF SEN PROTECT -68V +68V -18V +18V SC PNP SC NPN AGND +62V +62V -62V -62V AGND AGND AGND ISCTRIG AC OFF SEN PROTECT -68V +68V -18V +18V SC PNP SC NPN AGND +62V +62V -62V -62V AGN

24、D AGND AGND ISCTRIG AC OFF SEN PROTECT -68V +68V -18V +18V SC PNP SC NPN AGND +62V +62V -62V -62V AGND AGND AGND ISCTRIG AC OFF SEN PROTECT -68V +68V -18V +18V SC PNP SC NPN AGND +62V +62V -62V -62V AGND AGND AGND ISCTRIG AC OFF SEN PROTECT -68V +68V -18V +18V SC PNP SC NPN AGND +62V +62V -62V -62V

25、AGND AGND AGND ISCTRIG AC OFF SEN PROTECT -68V +68V -18V +18V SC PNP SC NPN SCN_4 SCP_4 +18V -18V +68V -68V PROT1 SEN1 ACOFF +62V_4A +62V_4A -62V_4A -62V_4A AGND4A AGND4A AGND4A ISCTRIG_1 STBY STBY +8V +8V PROT4 PROT3 PROT5 PROT2 PROT6 PROT1 PROT7 DGND DGND SCLED SCLED AGND SEN1 SEN2 SEN7 SEN3 SEN6

26、SEN4 AGND SEN5 ISCTRIG_1 ISCTRIG_2 ISCTRIG_3 ISCTRIG_4 ISCTRIG_5 ISCTRIG_6 ISCTRIG_7 DGND SCN_4 SCP_4 +18V -18V +68V -68V PROT1 SEN1 ACOFF +62V_4A +62V_4A -62V_4A -62V_4A AGND4A AGND4A AGND4A ISCTRIG_1 SCN_4 SCP_4 +18V -18V +68V -68V PROT1 SEN1 ACOFF +62V_4A +62V_4A -62V_4A -62V_4A AGND4A AGND4A AGN

27、D4A ISCTRIG_1 SCN_4 SCP_4 +18V -18V +68V -68V PROT1 SEN1 ACOFF +62V_4A +62V_4A -62V_4A -62V_4A AGND4A AGND4A AGND4A ISCTRIG_1 SCN_4 SCP_4 +18V -18V +68V -68V PROT1 SEN1 ACOFF +62V_4A +62V_4A -62V_4A -62V_4A AGND4A AGND4A AGND4A ISCTRIG_1 SCN_4 SCP_4 +18V -18V +68V -68V PROT1 SEN1 ACOFF +62V_4A +62V_

28、4A -62V_4A -62V_4A AGND4A AGND4A AGND4A ISCTRIG_1 SCN_4 SCP_4 +18V -18V +68V -68V PROT1 SEN1 ACOFF +62V_4A +62V_4A -62V_4A -62V_4A AGND4A AGND4A AGND4A ISCTRIG_1 STBY +8V DGND SCLED SCN_3 SCN_4 SCP_3 SCP_4 +62V_3 -62V_3 +62V_4 -62V_4 DGND -18V +18V ACOFF +70V -70V FAN3 FAN2 FAN1 DGND FAN1 DGND FAN2

29、DGND DGND FAN3 +12VD PROT1 PROT2 PROT3 PROT4 PROT5 PROT6 PROT7 SCLED DGND +5VD STBYLED ACIN I/V DGND ACOUT +5VD RELAY 15V 15V AGND1 64V 64V 38V 38V AGND2 53V 53V ON/OFF STBY DGND -18V +18V ACOFF +70V -70V FAN3 FAN2 FAN1 DGND STBY +8V DGND SCLED SCN_3 SCN_4 SCP_3 SCP_4 +62V_3 -62V_3 +62V_4 -62V_4 DGN

30、D STBYLED GREEN PROT1 STBYLED PROT3 +12VD PROT2 PROT4 +5VD PROT6 PROT5 SCLED PROT7 DGND DGND STBYLED GREEN ON/OFF STBY STBY STBY +8V +8V PROT4 PROT3 PROT5 PROT2 PROT6 PROT1 PROT7 DGND DGND SCLED SCLED AGND SEN1 SEN2 SEN7 SEN3 SEN6 SEN4 AGND SEN5 ISCTRIG_1 ISCTRIG_2 ISCTRIG_3 ISCTRIG_4 ISCTRIG_5 ISCT

31、RIG_6 ISCTRIG_7 DGND +62V_4A +62V_4A -62V_4A -62V_4A AGND4A AGND4A AGND4A ISCTRIG_1 +62V_4A +62V_4A -62V_4A -62V_4A AGND4A AGND4A AGND4A ISCTRIG_1 +62V_4A +62V_4A -62V_4A -62V_4A AGND4A AGND4A AGND4A ISCTRIG_1 +62V_4A +62V_4A -62V_4A -62V_4A AGND4A AGND4A AGND4A ISCTRIG_1 TO P611BTO P604B TO P612BTO

32、 P605B TO P613B TO P606B TO P614BTO P607B TO P615BTO P608B TO P616BTO P609B TO P617B TO P610B POWER SWITCH BOARDSTANDBY BOARDMAIN TRANSFORMER DISPLAY BOARD POWER LED BOARD THERMAL PROTECT BOARD POWER SUPPLY BOARD CONNECTION BOARD POWERAMP MODULE BOARDPOWERAMP MODULE BOARDPOWERAMP MODULE BOARDPOWERAM

33、P MODULE BOARDPOWERAMP MODULE BOARDPOWERAMP MODULE BOARDPOWERAMP MODULE BOARD FROM P204BFROM P205B FROM P203B TO P603BTO P602BTO P601B TRIGGER BOARD TO P401B FROM P618B FROM P201ATO P620B CHANNEL 1CHANNEL 2CHANNEL 3CHANNEL 4CHANNEL 5CHANNEL 6CHANNEL 7 TO CH1 P101ATO CH1 P102A TO CH2 P101ATO CH2 P102

34、A TO CH3 P101ATO CH3 P102A TO CH4 P101ATO CH4 P102A TO CH5 P101ATO CH5 P102A TO CH6 P101ATO CH6 P102A TO CH7 P101ATO CH7 P102A FROM P202A TO FAN1TO FAN2TO FAN3 TO P301A TO P506B FROM P207A FROM P801A FROM P2AFROM P1A TO P503B FROM AC INLETFROM FUSE TO P4ATO P3A TO J901 FROM J204 TO P619B FROM P206B

35、FROM P302 TO P701A TO P209BTO P208B TO P504BTO P505B 120 deg thermal breaker P623B 2PIN2.54-C P623B 2PIN2.54-C 1 2 P301A 12P2.0-A350B P301A 12P2.0-A350B 1 2 3 4 5 6 7 8 9 10 11 12 P401B 12PIN2.0-C P401B 12PIN2.0-C 1 2 3 4 5 6 7 8 9 10 11 12 P609B MOLEX 26-01-1099 P609B MOLEX 26-01-1099 1 2 3 4 5 6 7

36、 8 9 P101A MOLEX 41662 P101A MOLEX 41662 1 2 3 4 5 6 7 8 9 P604B MOLEX 26-01-1099 P604B MOLEX 26-01-1099 1 2 3 4 5 6 7 8 9 J102 BINDDING POST J102 BINDDING POST 1 2 P209B 5PIN3.96-C P209B 5PIN3.96-C 1 2 4 5 3 P616B MOLEX 26-01-1099 P616B MOLEX 26-01-1099 1 2 3 4 5 6 7 8 9 J101 RCA J101 RCA 1 2 P619B

37、 MOLEX 26-01-1089 P619B MOLEX 26-01-1089 1 2 3 4 5 6 7 8 t TR1 T973MKII-B MAIN TRANSFORMER t TR1 T973MKII-B MAIN TRANSFORMER 1 2 14 3 4 5 6 7 8 9 10 11 13 15 16 17 P612B MOLEX 26-01-1099 P612B MOLEX 26-01-1099 1 2 3 4 5 6 7 8 9 P611B MOLEX 26-01-1099 P611B MOLEX 26-01-1099 1 2 3 4 5 6 7 8 9 J101 RCA

38、 J101 RCA 1 2 CONTACTS UPSIDE P602B MOLEX 52207-1690 CONTACTS UPSIDE P602B MOLEX 52207-1690 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 1718 TP902 115deg THERMAL CIRCUIT BREAKER TP902 115deg THERMAL CIRCUIT BREAKER 12 P206B 12PIN2.0-C P206B 12PIN2.0-C 1 2 3 4 5 6 7 8 9 10 11 12 TP904 115deg THERMAL CIRCU

39、IT BREAKER TP904 115deg THERMAL CIRCUIT BREAKER 12 FAN3 FAN FAN3 FAN 1 2 R1A1 47 R1A1 47 TP901 115deg THERMAL CIRCUIT BREAKER TP901 115deg THERMAL CIRCUIT BREAKER 12 J204 2PIN2.54 J204 2PIN2.54 1 2 P203B 10PIN2.54-A60B P203B 10PIN2.54-A60B 2 3 4 1 5 6 7 8 9 10 P622B 2PIN2.54-C P622B 2PIN2.54-C 1 2 P

40、621B 2PIN2.54-C P621B 2PIN2.54-C 1 2 J102 BINDDING POST J102 BINDDING POST 1 2 P617B MOLEX 26-01-1099 P617B MOLEX 26-01-1099 1 2 3 4 5 6 7 8 9 J101 RCA J101 RCA 1 2 P613B MOLEX 26-01-1099 P613B MOLEX 26-01-1099 1 2 3 4 5 6 7 8 9 D701 L-519EGW D701 L-519EGW C GR TP903 115deg THERMAL CIRCUIT BREAKER T

41、P903 115deg THERMAL CIRCUIT BREAKER 12 P102A MOLEX 41662 P102A MOLEX 41662 1 2 3 4 5 6 7 8 9 R1A1 47 R1A1 47 J102 BINDDING POST J102 BINDDING POST 1 2 P101A MOLEX 41662 P101A MOLEX 41662 1 2 3 4 5 6 7 8 9 P205B FLEX CONNECTOR DIP16 P205B FLEX CONNECTOR DIP16 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 J1

42、01 RCA J101 RCA 1 2 P201A MOLEX 41662 P201A MOLEX 41662 1 2 3 4 5 6 7 8 P501B PCFS2508 P501B PCFS2508 1 2 P4A MOLEX_51144-0500 P4A MOLEX_51144-0500 1 2 3 4 5 P204B FLEX CONNECTOR DIP16 P204B FLEX CONNECTOR DIP16 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 J102 BINDDING POST J102 BINDDING POST 1 2 P101A M

43、OLEX 41662 P101A MOLEX 41662 1 2 3 4 5 6 7 8 9 J901 2PIN2.54 J901 2PIN2.54 1 2 P605B MOLEX 26-01-1099 P605B MOLEX 26-01-1099 1 2 3 4 5 6 7 8 9 FAN2 FAN FAN2 FAN 1 2 J102 BINDDING POST J102 BINDDING POST 1 2 R1A1 47 R1A1 47 P505B MOLEX 43160-2104 P505B MOLEX 43160-2104 1 2 3 4 CONTACTS UPSIDE P601B M

44、OLEX 52207-1690 CONTACTS UPSIDE P601B MOLEX 52207-1690 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 1718 P620B MOLEX 26-01-1089 P620B MOLEX 26-01-1089 1 2 3 4 5 6 7 8 P2A MOLEX_51144-0200 P2A MOLEX_51144-0200 1 2 U4 AC INLET U4 AC INLET P801A 2PIN2.54-A100B P801A 2PIN2.54-A100B 2 1 P615B MOLEX 26-01-1099

45、P615B MOLEX 26-01-1099 1 2 3 4 5 6 7 8 9 R1A11 47 R1A11 47 W3W3 P618B 12PIN2.0-A580B P618B 12PIN2.0-A580B 2 3 4 1 5 6 7 8 9 10 11 12 F1 FUSE HOLDER F1 FUSE HOLDER J101 RCA J101 RCA 1 2 P606B MOLEX 26-01-1099 P606B MOLEX 26-01-1099 1 2 3 4 5 6 7 8 9 J102 BINDDING POST J102 BINDDING POST 1 2 J107 RCA

46、J107 RCA 1 2 P607B MOLEX 26-01-1099 P607B MOLEX 26-01-1099 1 2 3 4 5 6 7 8 9 P603B 10PIN2.54-C P603B 10PIN2.54-C 1 2 3 4 5 6 7 8 9 10 1112 S801 SDDLB1027U-RN S801 SDDLB1027U-RN 12 P608B MOLEX 26-01-1099 P608B MOLEX 26-01-1099 1 2 3 4 5 6 7 8 9 P102A MOLEX 41662 P102A MOLEX 41662 1 2 3 4 5 6 7 8 9 P101A MOLEX 41662 P101A MOLEX 41662 1 2