NAD-T973_MKIIB-pwr-sm 维修电路原理图.pdf

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1、? ? ? ? ? ? ? ? ? ? ? ? ? ? ?RadioFans.CN 收音机爱 好者资料库CONTENTSFRONT PANEL/REAR PANEL VIEW? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?3SPECIFICATIONS? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?

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

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

4、 ? ? ? ? ? ? ? ? ? 18-26ELECTRICAL PARTS LIST? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?27-39EXPLODED VIEW? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 40EXPLODED VIEW PART

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

6、? ? ? ? ? ? ? ? ? 43SERVICE SAFETY PRECAUTIONS1. Replacing the FusesCAUTION: FOR CONTINUED PROTECTION AGAINST THE RISK OF FIREREPLACE ONLY WITH SAME TYPE OF FUSE.REFERENCE NO.PART NUMBERDESCRIPTIONRear PanelAH20-11203-10MDA T20AL/250VC20-12103-20MDA T10AL/250VAMP BoardF101/F10220-12632-00T6.3AL/250V

7、PSU BoardF201-F20420-12162-01T1.6AL/250VNOTE:*AH : North American version only*C: European version only2. Safety-check out (North American model only)Before returning the product to the customer, make leakage current orresistance measurements to determine that exposed parts are acceptablyinsulated f

8、rom the supply circuit.Parts marked with the symbolare critical with regard to the risk of fire andelectric shock.Replace only parts recommended by the manufacturer.- 2 -RadioFans.CN 收音机爱 好者资料库?- 3 - 4 -SPECIFICATIONSCONTINUOUS AVERAGE POWER?120 W (20.8 dBW)OUTPUT INTO 8 OHMS OR 4 OHMS(Min. power pe

9、r channel, 20 Hz 20 kHz, bothchannels driven, with no more than rateddistortion)Rated Distortion?0.03%(THD 20 Hz 20 kHz)Clipping power?150 W(21.8 dBW)(maximum continuous 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:?

10、420 W (26.2 dBW)Damping factor200(ref. 8 ohms 50Hz)Input ImpedanceR = 1 MohmsC = 180 pFInput sensitivity (for rated output into 8 ohms)1100mV+/-50mVVoltage gain29 dBFrequency response 20 Hz 20 kHz?0.2 dB- 3dB at 3 Hz/100 kHzSignal / Noise ratio, A-weighted96 dB ref. 1 W116 dB ref. 120WDIMENSIONS AND

11、 WEIGHTSNet Weight31 kg (68.0 Ib)Shipping Weight33 kg (72 Ib)Dimension (WHD)435 180 450mmIMPORTANT REPLACEMENT MODULE PROCEDUREMany of the PCB modules 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

12、,T973MKII-A,and T973MKII-B service personnel should adhere to in the following two pages:1) T973 and T973MKII-A PowerAMP moduleThe PowerAMP module (AH P/N:01-97501-10 and C P/N:01-97501-20) of the T975 can be usedas direct replacements for the PowerAMP module of the T973 and the T973MKII-A.When repl

13、acing the T973 PowerAMP module with the T975 PowerAMP module, one must replaceall the T973 PowerAMP modules with T975 PowerAMP modules.There will only be one venison of PowerAMP module available for repair; the T975 PowerAMPmodule. DO NOTmix T973, T973MKII-A and T975 PowerAMP modules.IMPORTANT NOTES

14、:Check that the Trigger board is the newer type; R401, R402, R403, R404 are 24kOhm resistors,and D401, D402, D403, D404 are 24V Zener Diodes. 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 T

15、975 servicemanual for the T975 PowerAMP module.2) T973MKII-B PowerAMP module The PowerAMP module (AH P/N:01-97501-10 and C P/N:01-97501-20) of the T975 can be usedas direct replacements for the PowerAMP module of the T973MKII-B.3) T973 and T973MKII-A Power supply boardThe Power supply board (P/N:01-

16、97502-00) of the T975 cannot be used as direct replacement Power supply board of the T973 and T973MKII-A. The Power supply board (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 w

17、ill 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 part number being 14-97506-01.14-97506-01- 5 -4) T973MKII-B Power supply boardThe Power supply board (P/N:01-97502-00) of the T975 can be used as a direct replacement for the

18、Power supply board of the T973MKII-B.5) T973, T973MKII-A, and T973MKII-B Display board (Including Power LED board)The Display board (P/N:01-97503-00) of the T975 cannot be used as a direct replacement Displayboard of the T973MKII-B. The Display board (PN: 01-97503-99) will be the replacement partfor

19、 the T973MKII-B Display board. The difference between the T975 Display board and the T973Display board is the double colour 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) s

20、hould be replaced with display board (P/N:01-97503-99).The difference between the T975 Display board and Power LED replacement 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

21、T973MKII-A Standby boardThe Standby board (AH P/N:01-97505-10, C P/N:01-97505-20) of T975 cannot be used as direct replacement Standby board of T973 and T973MKII-A. The Standby board (AHP/N: 01-97505-98 and C P/N: 01-97505-99) will be the replacement part for the T973 andT973MKII-A Standby board. 7)

22、 T973MKII-B Standby boardThe Standby board (AH P/N:01-97505-10, C P/N:01-97505-20) of the T975 can be used as adirect replacement for the Standby board of theT973MKII-B. 8) T973, T973MKII-A, and T973MKII-B Trigger boardThe Trigger board (P/N:01-97504-00) of the T975 can be used as a direct replaceme

23、nt triggerboard for the T973MKII-A and T973MKII-B.9) T973, T973MKII-A, and T973MKII-B Connection board The Connection board (P/N:01-97506-00) of the T975 can be used as a direct replacementConnection board for the T973, T973MKII-A, and T973MKII-B.10) T973, T973MKII-A, and T973MKII-B Power switch boa

24、rdThe Power switch board (P/N? 01-97508-00) of the T975 can be used as a direct replacementPower switch 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 boardfor the T973MKII-B. - 6 -ALIGNMENT PR

25、OCEDURE A. THERMAL SENSE ADJUSTMENTThis adjustment should be always done when the T973MKII-B is cool condition. (Thatmeans 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 toavoid that the

26、 Idling current heats up the unit excessively) At ambient temperature of 25 Cdegrees and when the unit is just turned on (still in cool condition), adjust the potRV103 (as marked as “Thermal Sense ADJ” in below drawing) for a voltage between theTHERMAL TEST POINT and AGND to be 750mV+/-10mV. If the

27、ambient temperature isdifferent, the voltage setting should be changed by 20mV per degree difference. So at20C degrees, the voltage should be 850mV+/-10mV; and at 30C degrees, the voltageshould be 650mV+/-10mV, etc. B. DC OFFSET VOLTAGEThe DC OFFSET between OFFSET Test Point and AGND must be within

28、0+/-3mV. If itsfound to be out of this range, change the TL084BCD to one selected for low offset voltageto meet the requirement.C. IDLING CURRENT: T973, T973MKII-A, and T973MKII-B PowerAMP ModuleThe idling current in the output stage of the poweramp should be set to 40mA+/-10mAper pnp-npn transistor

29、 pair. (This means the mid point voltage is 8mV with down limit of7mV and up limit 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 Testpoint 1 and 2. Then preheat the unit for 5 minutes, let idling

30、current settled and then readjustto 8mV +/- 1mV.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 8mV +/-1mV during the adjustment, due to the influenceof varied ambient temperature and mains voltage etc., the idling cur

31、rent will drift aftersome time. During the normal checking of idling current in the service field, its acceptableas long as the voltage is in the range of 7mV9mV.C. IDLING CURRENT: T975 PowerAMP ModuleThe idling current in the output stage of the poweramp should be set to 40mA+/-10mAper pnp-npn tran

32、sistor pair (This means the mid point voltage is 17.6mV with down limit of13.2mV and up limit of 22mV). The alignment procedure is: At first, adjust RV102 (Markedas “Idling Current ADJ” in the drawing below) for a voltage of 17.6mV +/- 1mV betweenTest point 1 and 2. Then preheat the unit for 5 minut

33、es, let idling current settled and thenreadjust to 17.6mV +/- 1mV.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 theinfluence of varied ambient temperature and mains voltage

34、 etc., the idling current will driftafter some time. During the normal checking of idling current in the service field, itsacceptable 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

35、starts turning). Turn of 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 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 1k

36、Hz, 0.5 W at 4 Ohmsload, monitor if the voltage at TP1 of J201 is negative, if not, adjust Pot RV201 justto 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 SENSITI

37、VITYD. ISC SENSITIVITYThe ISC sensing voltage can allow 0mV+/-50mV. But, for the alignment process duringproduction, 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 TESTPOINT” and AGND to be 0m

38、V+/-10mV.(Pls note the ISC should be adjusted when all modules are plugged in. Its not possible to get0mV +/-10mV if any of the modules are removed.)E. Fan Cut Of Point Adjustment T973MKII-BE. Fan Cut Of Point Adjustment T973MKII-BCheck the Fan sense voltage frst. Turn Pot RV201 to the end clockwise

39、 and confrm TP1of J201 is in negative voltage. 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-62VAGNDAGNDAG

40、NDISCTRIGAC OFFSENPROTECT-68V+68V-18V+18VSC PNPSC NPNAGND+62V+62V-62V-62VAGNDAGNDAGNDISCTRIGAC OFFSENPROTECT-68V+68V-18V+18VSC PNPSC NPNAGND+62V+62V-62V-62VAGNDAGNDAGNDISCTRIGAC OFFSENPROTECT-68V+68V-18V+18VSC PNPSC NPNAGND+62V+62V-62V-62VAGNDAGNDAGNDISCTRIGAC OFFSENPROTECT-68V+68V-18V+18VSC PNPSC N

41、PNAGND+62V+62V-62V-62VAGNDAGNDAGNDISCTRIGAC OFFSENPROTECT-68V+68V-18V+18VSC PNPSC NPNAGND+62V+62V-62V-62VAGNDAGNDAGNDISCTRIGAC OFFSENPROTECT-68V+68V-18V+18VSC PNPSC NPNAGND+62V+62V-62V-62VAGNDAGNDAGNDISCTRIGAC OFFSENPROTECT-68V+68V-18V+18VSC PNPSC NPNSCN_4SCP_4+18V-18V+68V-68VPROT1SEN1ACOFF+62V_4A+6

42、2V_4A-62V_4A-62V_4AAGND4AAGND4AAGND4AISCTRIG_1STBYSTBY+8V+8VPROT4PROT3PROT5PROT2PROT6PROT1PROT7DGNDDGNDSCLEDSCLEDAGNDSEN1SEN2SEN7SEN3SEN6SEN4AGNDSEN5ISCTRIG_1ISCTRIG_2ISCTRIG_3ISCTRIG_4ISCTRIG_5ISCTRIG_6ISCTRIG_7DGNDSCN_4SCP_4+18V-18V+68V-68VPROT1SEN1ACOFF+62V_4A+62V_4A-62V_4A-62V_4AAGND4AAGND4AAGND

43、4AISCTRIG_1SCN_4SCP_4+18V-18V+68V-68VPROT1SEN1ACOFF+62V_4A+62V_4A-62V_4A-62V_4AAGND4AAGND4AAGND4AISCTRIG_1SCN_4SCP_4+18V-18V+68V-68VPROT1SEN1ACOFF+62V_4A+62V_4A-62V_4A-62V_4AAGND4AAGND4AAGND4AISCTRIG_1SCN_4SCP_4+18V-18V+68V-68VPROT1SEN1ACOFF+62V_4A+62V_4A-62V_4A-62V_4AAGND4AAGND4AAGND4AISCTRIG_1SCN_

44、4SCP_4+18V-18V+68V-68VPROT1SEN1ACOFF+62V_4A+62V_4A-62V_4A-62V_4AAGND4AAGND4AAGND4AISCTRIG_1SCN_4SCP_4+18V-18V+68V-68VPROT1SEN1ACOFF+62V_4A+62V_4A-62V_4A-62V_4AAGND4AAGND4AAGND4AISCTRIG_1STBY+8VDGNDSCLEDSCN_3SCN_4SCP_3SCP_4+62V_3-62V_3+62V_4-62V_4DGND-18V+18VACOFF+70V-70VFAN3FAN2FAN1DGNDFAN1DGNDFAN2D

45、GNDDGNDFAN3+12VDPROT1PROT2PROT3PROT4PROT5PROT6PROT7SCLEDDGND+5VDSTBYLEDACINI/VDGNDACOUT+5VDRELAY15V15VAGND164V64V38V38VAGND253V53VON/OFFSTBYDGND-18V+18VACOFF+70V-70VFAN3FAN2FAN1DGNDSTBY+8VDGNDSCLEDSCN_3SCN_4SCP_3SCP_4+62V_3-62V_3+62V_4-62V_4DGNDSTBYLEDGREENPROT1STBYLEDPROT3+12VDPROT2PROT4+5VDPROT6PR

46、OT5SCLEDPROT7DGNDDGNDSTBYLEDGREENON/OFFSTBYSTBYSTBY+8V+8VPROT4PROT3PROT5PROT2PROT6PROT1PROT7DGNDDGNDSCLEDSCLEDAGNDSEN1SEN2SEN7SEN3SEN6SEN4AGNDSEN5ISCTRIG_1ISCTRIG_2ISCTRIG_3ISCTRIG_4ISCTRIG_5ISCTRIG_6ISCTRIG_7DGND+62V_4A+62V_4A-62V_4A-62V_4AAGND4AAGND4AAGND4AISCTRIG_1+62V_4A+62V_4A-62V_4A-62V_4AAGND

47、4AAGND4AAGND4AISCTRIG_1+62V_4A+62V_4A-62V_4A-62V_4AAGND4AAGND4AAGND4AISCTRIG_1+62V_4A+62V_4A-62V_4A-62V_4AAGND4AAGND4AAGND4AISCTRIG_1TO P611BTO P604BTO P612BTO P605BTO P613BTO P606BTO P614BTO P607BTO P615BTO P608BTO P616BTO P609BTO P617BTO P610BPOWER SWITCH BOARDSTANDBY BOARDMAIN TRANSFORMERDISPLAY

48、BOARDPOWER LED BOARDTHERMAL PROTECT BOARDPOWER SUPPLY BOARDCONNECTION BOARDPOWERAMP MODULE BOARDPOWERAMP MODULE BOARDPOWERAMP MODULE BOARDPOWERAMP MODULE BOARDPOWERAMP MODULE BOARDPOWERAMP MODULE BOARDPOWERAMP MODULE BOARDFROM P204BFROM P205BFROM P203BTO P603BTO P602BTO P601BTRIGGER BOARDTO P401BFRO

49、M P618BFROM P201ATO P620BCHANNEL 1CHANNEL 2CHANNEL 3CHANNEL 4CHANNEL 5CHANNEL 6CHANNEL 7TO CH1 P101ATO CH1 P102ATO CH2 P101ATO CH2 P102ATO CH3 P101ATO CH3 P102ATO CH4 P101ATO CH4 P102ATO CH5 P101ATO CH5 P102ATO CH6 P101ATO CH6 P102ATO CH7 P101ATO CH7 P102AFROM P202ATO FAN1TO FAN2TO FAN3TO P301ATO P5

50、06BFROM P207AFROM P801AFROM P2AFROM P1ATO P503BFROM AC INLETFROM FUSETO P4ATO P3ATO J901FROM J204TO P619BFROM P206BFROM P302TO P701ATO P209BTO P208BTO P504BTO P505B120 deg thermal breakerCONTACTS UPSIDEP601BMOLEX 52207-1690CONTACTS UPSIDEP601BMOLEX 52207-1690123456789101112131415161718J101RCAJ101RCA