NAD-T977-pwr-sm 维修电路原理图.pdf
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1、LAUNAMECIVRESLAUNAMECIVREST977 C/AHDEL:OMT977LAUNAMECIVRES NAD 2012NAD ELECTRONICS INTERNATIONALTORONTOT977HA/CRE I F I LPMA LENNAHC NEVEST977HA/CRE I F I LPMA LENNAHC NEVESSEVEN CHANNEL AMPLIFIERRadioFans.CN 收音机爱 好者资料库CONTENTS FRONT PANEL/REAR PANEL VIEW 3 SPECIFICATIONS 4 ALIGNMENT PROCEDURE/ALIGN
2、MENT POINTS 5-6 WIRING DIAGRAM 7 SCHEMATIC DIAGRAM 8-15 PCB LAYOUT 16-21 ELECTRICAL PARTS LIST 22-37 EXPLODED VIEW 38 EXPLODED VIEW PARTS LIST 39 PACKING DIAGRAM 40 SERVICE SAFETY PRECAUTIONS 1. Replacing the Fuses CAUTION: FOR CONTINUED PROTECTION AGAINST THE RISK OF FIRE REPLACE ONLY WITH SAME TYP
3、E OF FUSE. REFERENCE NO. PART NUMBER DESCRIPTION Rear Panel AH 20-11203-10 MDA T20AL/250V C 20-12103-20 MDA T10AL/250V AMP Board F101/F102 20-12632-00 T6.3AL/250V PSU Board F201-F204 20-12162-01 T1.6AL/250V NOTE: *AH : North American version only *C : European version only 2. Safety-check out (North
4、 American model only) 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 o
5、nly parts recommended by the manufacturer. - 2 - RadioFans.CN 收音机爱 好者资料库- 3 - - 4 - SPECIFICATIONS CONTINUOUS 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
6、 20 kHz) Clipping power 170 W(22.3 dBW) (maximum continuous power per channel). IHF dynamic power (Maximum short term power per channel) 8 ohms: 230 W (23.6 dBW) 4 ohms: 390 W (25.9 dBW) 2 ohms: 450 W (26.5 dBW) Time to go to Standby mode at no input signal 30 minutes Damping factor 300 (ref. 8 ohms
7、 50Hz) Input Impedance R = 1 Mohms C = 180 pF Input sensitivity (for rated output into 8 ohms) 1180mV+/-50mV Voltage gain 29 dB Frequency response 20 Hz 20 kHz 0.2 dB - 3dB at 3 Hz/100 kHz Signal / Noise ratio, A-weighted 96 dB ref. 1 W 125 dB ref. 140W DIMENSIONS AND WEIGHTS Net Weight 32.3 kg (71.
8、2 Ib) Shipping Weight 36.5 kg (80.5 Ib) Dimension (WHD) 435 194 476mm ALIGNMENT PROCEDURE (T977) A. THERMAL SENSE ADJUSTMENT This adjustment should be always done when the T977 is cool condition. (That means the temperature inside the unit should be almost same as the ambient temperature. Connector
9、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 the unit is just turned on (still in cool condition), adjust the pot RV103(as marked as “Thermal Sense ADJ” in below d
10、rawing) 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 difference. So at 20C degrees, the voltage should be 850mV+/-10mV; and at 30C degrees, the voltage should be 650mV+/-10m
11、V, 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 low offset voltage to meet the requirement. C. IDLING CURRENT The idling current in the output stage of the poweramp sho
12、uld 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 procedure is: At first, adjust RV102 (Marked as “Idling Current ADJ” in the drawing below) for a voltage of 17.6mV +/- 1mV between Test poi
13、nt 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 all modules are assembled into the unit. 2. Though the idling current is set as 17.6mV +/-1mV during the adjustment, due to the influ
14、ence 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 field, its acceptable as long as the voltage is in the range of 13.2mV22.0mV. D. ISC SENSITIVITY The ISC sensing voltage can allow 0mV
15、+/-50mV. But, for the alignment process in our factory, 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 when all mod
16、ules 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 Pot RV201 to the end clockwise and confirm TP2 of J201 is in negative voltage. Run the unit to heat it up and drive the fan to start tu
17、rning, - 5 - 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 off 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 Pot RV201.
18、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, monitor if the voltage at TP1 of Pot RV201 is negative, if not, adjust Pot RV201 just to the point that TP1 changes from positive to negative (to ge
19、t the fans just start turning). Finally, turn off the signal and monitor if fans stop turning within about 30s Max. - 6 - AGND+62V+62V-62V-62VAGNDAGNDAGNDISCTRIGAC OFFSENPROTECT-68V+68V-18V+18VSC PNPSC NPNAGND+62V+62V-62V-62VAGNDAGNDAGNDISCTRIGAC OFFSENPROTECT-68V+68V-18V+18VSC PNPSC NPNAGND+62V+62V
20、-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 NPNAGND+62V+62V-62V-62VAGNDAGNDAGNDISCTRIGAC OFFSENPROTECT-68V+68V
21、-18V+18VSC PNPSC NPNAGND+62V+62V-62V-62VAGNDAGNDAGNDISCTRIGAC OFFSENPROTECT-68V+68V-18V+18VSC PNPSC NPNSCN_4SCP_4+18V-18V+68V-68VPROT1SEN1ACOFF+62V_4A+62V_4A-62V_4A-62V_4AAGND4AAGND4AAGND4AISCTRIG_1STBYSTBY+8V+8VPROT4PROT3PROT5PROT2PROT6PROT1PROT7DGNDDGNDSCLEDSCLEDAGNDSEN1SEN2SEN7SEN3SEN6SEN4AGNDSEN
22、5ISCTRIG_1ISCTRIG_2ISCTRIG_3ISCTRIG_4ISCTRIG_5ISCTRIG_6ISCTRIG_7DGNDSCN_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+6
23、2V_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_4SCP_4+18V-18V+68V-68VPROT1SEN1ACOFF+62V_4A+62V_4A-62
24、V_4A-62V_4AAGND4AAGND4AAGND4AISCTRIG_1STBY+8VDGNDSCLEDSCN_3SCN_4SCP_3SCP_4+62V_3-62V_3+62V_4-62V_4DGND-18V+18VACOFF+70V-70VFAN3FAN2FAN1DGNDFAN1DGNDFAN2DGNDDGNDFAN3+12VDPROT1PROT2PROT3PROT4PROT5PROT6PROT7SCLEDDGND+5VDSTBYLED15V15VAGND164V64V38V38VAGND253V53VON/OFFSTBYDGND-18V+18VACOFF+70V-70VFAN3FAN2
25、FAN1DGNDSTBY+8VDGNDSCLEDSCN_3SCN_4SCP_3SCP_4+62V_3-62V_3+62V_4-62V_4PROT1STBYLEDPROT3+12VDPROT2PROT4+5VDPROT6PROT5SCLEDPROT7DGNDON/OFFSTBYSTBYSTBY+8V+8VPROT4PROT3PROT5PROT2PROT6PROT1PROT7DGNDDGNDSCLEDSCLEDAGNDSEN1SEN2SEN7SEN3SEN6SEN4AGNDSEN5ISCTRIG_1ISCTRIG_2ISCTRIG_3ISCTRIG_4ISCTRIG_5ISCTRIG_6ISCTR
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