crown_d-75_dual_channel_power_amplifier_sm电路图.pdf

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1、0-75 DUAL-CHANNEL POWER AMPLIFIER SERVICE MANUAL CROWN INTERNATIONAL, INC. 1718 W. MISHAWAKA RD. ELKHART, IN 465174095 C 1989 Crown International. Inc. K80186A6 389 RadioFans.CN 收音机爱 好者资料库 FULL THREE-YEAR WARRANTY SUMMARY OF WARRANTY We, CROWN INTERNATIONAL. INC., 1718 West Mishawalca Road. Elkhart,

2、 Indiana46517-4095 (Narrantor) warrant to you. the ORIGINAL PURCHASER AND ANY SUBSEQUENT OWNER of each NEW Crown product, for a period of three (3) yeaTS from the date of purchase by the original purchaser (warranty period) lhal1hc product is free of defects in materials or workmanship :md will mcet

3、 or exceed all advcniscd specifications for such a product. ITEMS EXCLUDED FROM WARRANTY Weare not responsible forproducl failure !;8uscd by misu$(l, accidcntornegieci. This warranydoc$ not extend 0 any produl:lon which the serial number has been defaced, altered. or removed. It does nol cover damag

4、e 0 loudspeakers or any other products resulting from Crown product failure. It does nOI cover defcclS ordamagccauscd by your use OfWl8Uthoril.oo modifications, parts, or service. It also e)(clude$ batteries and damage caused by leaky or defective batteries. WHAT WE WILL DO We will remedy any defect

5、 in materials or workmanship by repair, replacement. or refund. We may not elect refund unless you agree, or ooless we are unable to provide replacement, and repair is not practical or cannot be timely made. If a rcfood iselccted, men you must make me derective or malfunctioning component available

6、10 Crown free and clear of all liens or other encumbrances. The refund will be equal to me actual purchase price, not including interest, insurance, closing costs, and other finance charges less a reasonable depreciation on the product from the dateof original purchase. Warranty work can only be per

7、formed at our authorized service centers or at the Crown factory. We will remedy the defect and ship the product from the sCJvice center or Crown factory within a reasonable time aftef receipt of the defective product at the aumoriz.cd service center or Crown factory. All e)(pcnses in remedying the

8、defect. including sUrfaceshippingcoslS in the United States. will be bome by Crown. (Purchaser must bear thee)(pensc of shipping (he product between any foreign country and the port of entry in the United States and all tues, duties. and other customs fee for such foreign shipments.) HOW TO OBTAIN W

9、ARRANTY SERVICE YOli must notify us of your need for warranty service not later than ninety (90) days after expiration of the warranty period. We will give you written ootice ofthcdcaler scrvice center. 10 whom you may dclivcrthe product. or we will give you an authorization 10 return it for factory

10、 service. All components must be shipped in a factory pack, which, if needed, may beobtained from Crown frec of charge. Corrcctive action will be taken within a reasonable time of the date of roceiptofthe defective product by us or our scrvicecentcr. If the repairs made by Crown or the authori7.cd s

11、erviceecnter arc not satisfactory, notify Crown or the authorized service center immediately. DISCLAIMER OF CONSEQUENTIAL AND INCIDENTAL DAMAGES YOU ARE NOT EmTTLED TO RECOVER FROM US ANY CONSEQUENTIAL OR INCIDENTAL DAMAGES RESULTING FROM ANY DEFECT IN OUR PRODUCT. THIS INCLUDES ANY DAMAGE TO ANOTHE

12、R PRODUCT OR PRODUcrS RESULTING FROM SUCH A DEFECT. SOME STATES 00 NOT ALLOW THE EXCLUSION OR LIMITATIONS OF INCroENTAL OR CONSEQUENTIAL OAMAGES,SOTHE ABOVE LIMITATION OR EXCLUSION MAY NOT APPLY TO YOU, WARRANTY ALTERATIONS NO PERSON HAS THE AUTHORITY TO ENLARGE, AMEND, OR MODIFY THIS WARRANTY. THE

13、WARRANTY IS NOT EXTENDED BY THE LENGTH OF TIME WHICH YOU ARE DEPRIVED OF THE USE OF THE PRODUCT. REP AIRS AND REPLACEMENT PARTS PROVlDEDUNDER THE TERMS OFTHIS WARRANTY SHALL CARRY ONLY THE UNEXPIRED PORTION OFTHIS WARRANTY. DESIGN CHANGES We reserve the right to change the design of any prodUCI from

14、 time to time without notice and with no obligation 0 make corrcsponding changes in products previously manufactured. LEGAL REMEDIES OF PURCHASER THIS WARRRANTY GIVES YOU SPECJFIC LEGAL RIGHTS, AND YOU MAY HA VEOTHER R1GHTS WHICH VAR Y FROM STATE TO STATE. No action to enforce this Warranty shal1 be

15、 commenced latcrthan ninety 9O)days after e)(piration of the warranty period. CROWN INTERNATIONAL, INC. 1718 West Mishawaka Road, Elkhart, Indiana 465174095. THIS STATEMENT OF WARRANTY SUPERSEDES ALL OTHERS CONTAINED IN THIS MANUAL 3/88 RadioFans.CN 收音机爱 好者资料库 The infonnation furnished in this manua

16、l does nO( include all of the details of design. production, or variations of theequipmenl. Nor does it cover every possible situation which may arise during installation, operation or maintenance. If you need special assistance., beyond the scope of (his manual, please contaCt the Cro . Tl Interr.a

17、tional Customer Services Dcpanment. Crown International, Inc. 1716 West Mishawaka Road Elkhart, Indiana 46517-4095 Phone: (219) 294-8000 Fax: (219) 294-6FAX Twx; (610) 294-2160 WARNING TO PREVENT SHOCK OR FIRE HAZARD, DO NOT EXPOSE TO RAIN OR MOISTURE! CAUTION TO PREVENT SHOCK DO NOT USE THE POLARIZ

18、ED AC PLUG OF THIS UNIT WITH AN llliPOLARIZED EXTENSION CORD, RECEPTACLE OR OTHER OUTLET WHERE THE BLADES CANNOT BE FULLY INSERTED. ATTENTION POUR PREVENIR LES CHOCS ELECTRIQUES NE PAS UTILISER cenE FICHE POLARISEE AVEC UN PROLONGATEUR. UNE PRISE DE COURANT OU UNE AUTRIE SORTIE DE COURANT, SAUF 51 L

19、ES LAMES PEUVENT ETRE INSEREES A FOND SANS EN LAISSER AUCUNE PARTIE A DECOUVERT. RadioFans.CN 收音机爱 好者资料库 9 (jllilllOll _ -o-,-z-, -PO:WE=Rc:.AM-PLIFc:IER-_ -REV-. 0 Table of Contents 1 Introduction _ . _ . _ . _ ._ ._ . _ . _ ._ . _ . _ . _ I-I 7 Specifications _ . _. _ ._._._._._._. _ ._. _ 7-1 1.1

20、 TheD-75 . 1-1 7.1 General . 7-1 1.2 Warramy . ,1-,1 7.2 Monaural, . 7-1 7.3 Stecoo . 7-2 2 Facilities. _ . _ . _._._ . _ . _._ . _._ 2-1 7.4 PcrfonnanceGraphs . 7-4 3 Required Test EquipmenL . _ . _ . 3-1 8 Schematics._ . _._ . _ . _ . _ . _ . _ ._ . _ . 8-1 4 Maintenance . 41 4.1 Safety First . 4-

21、1 4.2 Inspection . 4-1 4.3 Disassembly . 4- 4.4 Reassembly . 4-2 4.5 Troubleshooting . 4-2 9 Parts._ . _ . _ . _._._._ . _ ._._._ . _ . _ . 9-1 9.1 General Infonnat.ion . 9-1 9.2 Standard and Special Parts . 9- 9.3 Ordering PaIlS . 9-1 9.4 Shipment . 9- 9.5 Tenns . 9- 9.6 lIluSUatcd Parts Lists . 9-

22、2 5 Voltage Conversion _ ._._._._._._ . _. _ . _ 5-1 Appendics A: Installallon. _ ._ . _. A-I A.I Mounting . AI 6 Circuit Theory_ . _._._._. _ . _._._._._._ 6-1 A.2 Wiring . AI 6.1 Block Diagram Circuil Theory . 6 6.2 Balanced/Unbalanced Input Stage . 6-2 6.3 Input Operational Amplifier . 6-2 6.4 Si

23、gnal Translator . _ . 6-2 6.5 Final Voltage Amplifier . 6-3 A.2.1 SLCrco . A-I A.2.2 Monaural . A-I A.3 Input . AI A.4 OutpUI. . A-2 A.S Load Potcction . A3 6.6 Bias . 6-3 6.7 Output Stage . 63 Appendics B: Operation . _ . _ ._._ . 8-1 6.8 Protection Circuitry . 6-3 B.I Precautions . B-1 6.9 I)Cn.I

24、(InputlOutpu(Comparator) . 6-4 B.2 Controls . B-1 6.10 Signal Prcscnce Indicator . 6-4 B.3 PrOLCction . BI B.4 Fuse Rcplacemcnl . B-2 ill ustration 1.1 075 . . 2.1 Front Facilities (0.75) . . 2.2 Rear Facilities (075) . . 4.1 2 Ohm Load Wavefonn . . 4.2 10KHz Square Wave . . 4.3 20KHz Sine Wave . .

25、4.4 1M Distortion Test Se(up . . 4.5 Signal to Noise Test Setup . . 5.1 AC Mains Voltage Conversion . _ . . 6.1 0-75 Block Diagr$l . . 6.2 Balanced Input Stae . . 6.3 Input Operational Amplifier. . . 6.4 Signal Translator . . 6.5 Final Voltage.Amplifier . . ,., 2 22 4) 4-3 4) 44 44 51 6-1 6-2 62 62

26、6-3 6.6 Bias, Output and Protection Stages. 63 6.7 IOC . 64 6.8 Signal Presence Indicator . . 7.1 Power Matrix . . 7.2 Nominal Frequency Responce . . 7.3 Nominal Output Impzdance. . . 7.4 Nominal Phase Responce . . 7.5 Nominal Power Efficiency . . 7.6 Nominal Damping Factor . . 7.7 Nominal Output Ph

27、ase Angle . . 7.8 Nominal Crosstalk. . . 7.9 Nominal Noise Spectrum . . 8.1 0-75 Schematic Diagrams . . 9.1 0-75 Main Modules . . 9.2 Output Moduleoard illf is faulty and needs replacing. If this is the case, refer to the disais.embly instructions listed below. All other components on or around the

28、Output Module may be replaced without actual removal of the boa:d. This procedure is also listedbclow, after the disassembly instru:tions. I. Replacement a. Remove the Main Board (See Main Board Removal). b. Unsolder and remove the four Ourput transistors (25) by unscrewing the 8 mounting screws (tw

29、o on each). Note: In order to case replacement of spacers located beneath each screw!nut combination, leave the 0-75 in its normal/ying position-flat! c. Removc the four driver transistors (24) screws. d. Gently lift ooard upward, being careful not 10 jar the position of spacers located beTICath. c.

30、 Remove all external wiring to Output Module and note location for future ie-connection. f. Replace board. Maintenance 4-1 2. Repair 3 . All component parts localcd on the Output Module may be removed by applying standard soldering! desoldering methods (See Section 7) from the lOp of the board. Use

31、extra care when working with a pan localed near the front panel so as not to mar the finish. b. Front panel controls and LEDs may be replaced without removing the OutpUt Module Board (Sec the following section). 3. Output transistor replacement-Output transistor (25) can be replaced by removing two

32、mounting screws (per output) and unsoldering the twO main connecting pins. Note as per eploded view drawing insulating wafer (TO- 3,21), and its position in assembly. 4.3.4. Front Panel Pans Replacement As previously stated, all front panel componcm pans can be replaced without Output Module removal

33、. Generally. this operation is performed by unsoldering all or pan of obsuucting components. A detailed inslruCtion format is listed below. I. Input level control removal is accomplished by removing the aluminum knobs (28) and related hardware (20). Channel one pot can be pulled back and slid out th

34、e left-hand side when the headphone jack (15) and associaLed hardware is removed (10, 14) (rack ear (93) should be removed). Channel tWO input level pOlentiometer can be remove after the right lead of R232 is disconnected and the grounding bus strip is moved away from the working area. The potentiom

35、eler may need considerable, but gentle pressure in order for it to come free. 2. 10C. Signal LED Replacement. When handling any one of the four panel LEDs (22, 23), etrcme care is necessary in order 10 achieve a successful repair. Unsolder leads of LED 10 be replaced. With a pair of needle-nose plie

36、rs, remove the black suppon ring located behind the LED. Next carefully extract the faulty LED by pulling straight back and removing from the reat. Replace the LED and reverse of above. Note: When installing an LED always observe correct polariIY! It may be helpful when inserting the rear black supp

37、ort ring to apply pressure with a 1/4ft nut driver allowing the leads to move up the middle of the driver (See Fig. 7.17). 3. On/Off Switch Replacement To replace the front panel OfI/off switch (35) remove aluminum knob and related hardware (27. 2,10, II). With a small Oat-head screwdriver, slowly p

38、ry orr fuse bkx:k holder from adhesive. Push switch back until solder lugs are exposed. Remove wire. and slide the switch to the right and out the end. Replacement is the reverse of above. Note: It may be necessary to replace the adhesive strip located beneath the 4-2 Maintenanc9 fuse block. 4. Neon

39、 Orr-On Indicator Replacement. Because of the special mounting procedure used with the front panel power indicator (42), Crown recommends factory replacement only. 4.3.5. Back Panel Parts Replacement All component parts located on the back panel of the 0- 75 can be replaced with relatively littJe ef

40、fort (see exploded view drawing, rear panel assembly). Should quc. . tions arise eontact the Crown Technical Service Department. 4.4 Reassembly Reassembly is essentially the reverse of disassembly. If in doubt about types and sizes of attaching pans, refer 10 the appropriate illusuation in Section 9 4.5.Troubleshooting The three steps to effective troubleshOOl.ing and repair were mentioned earlier. They ean be summarized in the three following questions: What is the problem (effec!)? What