NAD-T973MKIIB-pwr-sm 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 PANEL VIEW? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?3 SPECIFICATIONS? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?

2、 ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 4 IMPORTANT REPLACEMENT MARK? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?5-6 ALIGNMENT PROCEDURE/ALIGNMENT POINTS? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 7-8 WIRING DIAGRAM? ? ? ? ? ? ? ? ? ? ? ? ? ?

3、? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?9 SCHEMATIC DIAGRAM? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 10-17 PCB LAYOUT? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?

4、? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 18-26 ELECTRICAL PARTS LIST? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?27-39 EXPLODED VIEW? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?

5、 ? ? ? ? ? ? ? 40 EXPLODED VIEW PARTS LIST? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?41 IMPORTANT REPLACEMENT P/N LIST (PARTS SUBSTITUTION). . . . . . . . . . . . . . . 42 PACKING DIAGRAM? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?

6、 ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 43 SERVICE SAFETY PRECAUTIONS 1. Replacing the Fuses CAUTION: FOR CONTINUED PROTECTION AGAINST THE RISK OF FIRE REPLACE ONLY WITH SAME TYPE OF FUSE. REFERENCE NO.PART NUMBERDESCRIPTION Rear Panel AH20-11203-10MDA T20AL/250V C20-12103-20MDA T10AL

7、/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) Before returning the product to the customer, make leakage current or resistance measurements to

8、 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 the manufacturer. - 2 - RadioFans.CN 收音机爱 好者资料库 ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? - 3 - Radi

9、oFans.CN 收音机爱 好者资料库 - 4 - SPECIFICATIONS CONTINUOUS AVERAGE POWER?120 W (20.8 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?150 W(21.8 dBW) (maximum continuou

10、s power per channel). IHF dynamic power (Maximum short term power per channel) 8 ohms:?200 W (23.0 dBW) 4 ohms:?360 W (25.6 dBW) 2 ohms:?420 W (26.2 dBW) Damping factor200 (ref. 8 ohms 50Hz) Input ImpedanceR = 1 Mohms C = 180 pF Input sensitivity (for rated output into 8 ohms)1100mV+/-50mV Voltage g

11、ain29 dB Frequency response 20 Hz 20 kHz?0.2 dB - 3dB at 3 Hz/100 kHz Signal / Noise ratio, A-weighted96 dB ref. 1 W 116 dB ref. 120W DIMENSIONS AND WEIGHTS Net Weight31 kg (68.0 Ib) Shipping Weight33 kg (72 Ib) Dimension (WHD)435 180 450mm IMPORTANT REPLACEMENT MODULE PROCEDURE Many of the PCB modu

12、les of T975 and T973MKII-B are similar. NAD will supply T975 modules for the various versions of T973. There are detail service instructions for the T973, T973MKII-A,and T973MKII-B service personnel should adhere to in the following two pages: 1) T973 and T973MKII-A PowerAMP module The PowerAMP modu

13、le (AH P/N:01-97501-10 and C P/N:01-97501-20) of the T975 can be used as direct replacements for the PowerAMP module of the T973 and the T973MKII-A. When replacing the T973 PowerAMP module with the T975 PowerAMP module, one must replace all the T973 PowerAMP modules with T975 PowerAMP modules. There

14、 will only be one venison of PowerAMP module available for repair; the T975 PowerAMP module. DO NOTmix T973, T973MKII-A and T975 PowerAMP modules. IMPORTANT NOTES: Check that the Trigger board is the newer type; R401, R402, R403, R404 are 24kOhm resistors, and D401, D402, D403, D404 are 24V Zener Di

15、odes. When ordering the T975 PowerAMP modules, order a new Trigger board as well. The idle current adjustment is now changed; use the adjustment procedure from the T975 service manual for the T975 PowerAMP module. 2) T973MKII-B PowerAMP module The PowerAMP module (AH P/N:01-97501-10 and C P/N:01-975

16、01-20) of the T975 can be used as direct replacements for the PowerAMP module of the T973MKII-B. 3) T973 and T973MKII-A Power supply board The Power supply board (P/N:01-97502-00) of the T975 cannot be used as direct replacement Power supply board of the T973 and T973MKII-A. The Power supply board (

17、P/N: 01-97502-99) will be the replacement part for the T973 and the T973MKII-A Power supply board. The T975 Power supply board has the addition of D227, D228, D229, which will be to be removed. Furthermore, the cable of P207A being a 6-wire cable will be replaced with a new 4-wire cable with its par

18、t number being 14-97506-01. 14-97506-01 - 5 - 4) T973MKII-B Power supply board The Power supply board (P/N:01-97502-00) of the T975 can be used as a direct replacement for the Power supply board of the T973MKII-B. 5) T973, T973MKII-A, and T973MKII-B Display board (Including Power LED board) The Disp

19、lay board (P/N:01-97503-00) of the T975 cannot be used as a direct replacement Display board of the T973MKII-B. The Display board (PN: 01-97503-99) will be the replacement part for the T973MKII-B Display board. The difference between the T975 Display board and the T973 Display board is the double co

20、lour LED. The LED is Red and Blue (P/N:33-50565-00) for the T975, and Red and Green (P/N:33-50525-02) for the T973, T973MKII-A, and T973MKII-B. The Power LED board (P/N:01-97507-99) should be replaced with display board (P/N:01-97503-99). The difference between the T975 Display board and Power LED r

21、eplacement is the double colour LED. The LED is Amber and Blue (P/N:33-50565-01) for the T975, and Amber and Green (P/N:33-50525-98) for the T973, T973MKII-A, and T973MKII-B. 6) T973 and T973MKII-A Standby board The Standby board (AH P/N:01-97505-10, C P/N:01-97505-20) of T975 cannot be used as dire

22、ct replacement Standby board of T973 and T973MKII-A. The Standby board (AH P/N: 01-97505-98 and C P/N: 01-97505-99) will be the replacement part for the T973 and T973MKII-A Standby board. 7) T973MKII-B Standby board The Standby board (AH P/N:01-97505-10, C P/N:01-97505-20) of the T975 can be used as

23、 a direct replacement for the Standby board of theT973MKII-B. 8) T973, T973MKII-A, and T973MKII-B Trigger board The Trigger board (P/N:01-97504-00) of the T975 can be used as a direct replacement trigger board for the T973MKII-A and T973MKII-B. 9) T973, T973MKII-A, and T973MKII-B Connection board Th

24、e Connection board (P/N:01-97506-00) of the T975 can be used as a direct replacement Connection board for the T973, T973MKII-A, and T973MKII-B. 10) T973, T973MKII-A, and T973MKII-B Power switch board The Power switch board (P/N? 01-97508-00) of the T975 can be used as a direct replacement Power swit

25、ch board for the T973, T973MKII-A, and T973MKII-B. 11) T973MKII-B TP board The TP board (P/N? 01-97509-00) of the T975 can be used as a direct replacement TP board for the T973MKII-B. - 6 - ALIGNMENT PROCEDURE A. THERMAL SENSE ADJUSTMENT This adjustment should be always done when the T973MKII-B is c

26、ool 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 that the Idling current heats up the unit excessively) At ambient temperature of 25 C degrees and when

27、 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 per degree

28、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 selected for

29、low offset voltage to meet the requirement. C. IDLING CURRENT: T973, T973MKII-A, and T973MKII-B PowerAMP Module 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 8mV with down limit of 7mV and up limi

30、t of 9mV). The alignment procedure is: At first, adjust RV102 (Marked as “Idling Current ADJ” in the drawing below) for a voltage of 8mV +/- 1mV between Test point 1 and 2. Then preheat the unit for 5 minutes, let idling current settled and then readjust to 8mV +/- 1mV. Pls note: 1.The idling curren

31、t must be adjusted when all modules are assembled into the unit. 2.Though the idling current is set as 8mV +/-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 curr

32、ent in the service field, its acceptable as long as the voltage is in the range of 7mV9mV. C. IDLING CURRENT: T975 PowerAMP Module 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 lim

33、it of 13.2mV and up limit of 22mV). The alignment procedure 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

34、. Pls note: 1.The idling current must be adjusted when all 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

35、the normal checking of idling current in the service field, its acceptable as long as the voltage is in the range of 13.2mV22.0mV. - 7 - For example, all 7 channels at 50W/4ohms for 10 minutes or 5 minutes or even less (as long as the fan can starts turning). Turn of the signal but still keep the un

36、it operating for 1 minute. Then run all 7 channels at 1kHz, 0.25W at 4 Ohms load monitor the voltage at TP1 of J201. Adjust RV201 to get the voltage from negative to positive to ensure that the Fans are turned of. Then run all 7 channels at 1kHz, 0.5 W at 4 Ohms load, monitor if the voltage at TP1 o

37、f 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 of the signal and monitor if fans stop turning withing about 30s Maximum. D. ISC SENSITIVITYD. ISC SENSITIVITY The ISC sensing voltage can all

38、ow 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 drawing) to get a voltage between the “ISC SENSE TEST POINT” and AGND to be 0mV+/-10mV. (Pls note the ISC should be adjusted whe

39、n all modules are plugged in. Its not possible to get 0mV +/-10mV if any of the modules are removed.) E. Fan Cut Of Point Adjustment T973MKII-BE. Fan Cut Of Point Adjustment T973MKII-B Check the Fan sense voltage frst. Turn Pot RV201 to the end clockwise and confrm TP1 of J201 is in negative voltage

40、. Run the unit to heat it up and drive the fan to start turning. ? ? ? ? ISC Adjustment (T973 & T973MKII-A) Idle Current Adjustment (T973 & T973MKII-A) ? ? ? ? Idle Current Adjustment (T973MKII-B & T975) ISC Adjustment (T973MKII-B & T975) - 8 - AGND +62V +62V -62V -62V AGND AGND AGND ISCTRIG AC OFF

41、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 AGND AGND AGND ISCTRIG AC O

42、FF 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 AGND AGND AGND ISCTRIG A

43、C 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 SEN4 AGND SEN5 ISCTRIG_1

44、 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 AGND4A ISCTRIG_1 SCN_4 SCP_

45、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_4A -62V_4A -62V_4A AGND4

46、A 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 DGND DGND FAN3 +12VD PRO

47、T1 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 DGND 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 ISCTRIG_