Crown-D45A-pwr-sm 电路图 维修手册.pdf

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1、D-45 / D-75A Amplifier Service Manual 1 POWER AMPLIFIER SERVICE MANUAL D-45 / D-75A Exported to select countries as Amcron. 1995 by CROWN INTERNATIONAL, INC. P.O. Box 1000, Elkhart, IN 46515-1000 Telephone: 219-294-8000 Shipping Address: 57620 C.R. 105 Elkhart, IN U.S.A. 46517 Amcron, Crown, and IOC

2、 are registered trademarks of Crown International, Inc. K-SD4575A 11-95 RadioFans.CN 收音机爱 好者资料库 D-45 / D-75A Amplifier Service Manual 2 The information furnished in this manual does not include all of the details of design, production, or variations of the equipment. Nor does it cover every possible

3、 situation which may arise during installation, operation or maintenance. If you need special assistance beyond the scope of this manual, please contact the Crown Technical Support Group. Mail: P.O. Box 1000 Elkhart IN 46515-1000 Shipping: 57620 C.R. 105 Elkhart IN 46517 Phone: (800) 342-6939/(219)

4、294-8200 Facsimile: (219) 294-8301 WARNING TO REDUCE THE RISK OF ELECTRIC SHOCK, DO NOT EXPOSE THIS EQUIPMENT TO RAIN OR MOISTURE! CAUTION TO PREVENT SHOCK DO NOT USE THE POLARIZED AC PLUG OF THIS UNIT WITH AN UNPOLARIZED EXTENTION CORD, RECEPTACLE OR OTHER OUTLET WHERE THE BLADES CANNOT BE FULLY IN

5、SERTED. ATTENTION POUR PREVENIR LES CHOCS ELECTRIQUES NE PAS UTILISER CETTE FICHE POLARISEE AVEC UN PROLONGATEUR. UNE PRISE DE COURANT OU UNE AUTRIE SORTIE DE COURANT, SAUF SI LES LAMES PEUVENT ETRE INSEREES A FOND SANS EN LAISSER AUCUNE PARTIE A DECOUVERT. RadioFans.CN 收音机爱 好者资料库 D-45 / D-75A Ampli

6、fier Service Manual 3 Table of Contents Introduction . 4 General Parts Information. 5 Specifications . 6 Circuit Theory . 7 Voltage Conversion . 10 Internal Settings. 11 Electrical Checkout Procedures . 12 Exploded View Parts List, Front. 14 Exploded View Parts List, Rear . 16 Q43308-8 Main Module C

7、omponent Layout. 18 Q43308-8 Main Module Parts List . 19 Q43156-1 Output Module Component Layout. 21 Q43156-1 and Q43309-6 Module Parts List . 22 RadioFans.CN 收音机爱 好者资料库 D-45 / D-75A Amplifier Service Manual 4 Introduction This manual contains service information on Crown power amplifiers. It is des

8、igned to be used in con- junction with the applicable Owners Manual. However, some important information is duplicated in this Ser- vice Manual in case the Owners Manual is not readily available. NOTE: THE INFORMATION IN THIS MANUAL IS INTENDED FOR USE BY AN EXPERIENCED TECHNICIAN ONLY. Scope This S

9、ervice Manual comes in several sections. The contents of each section apply to all models listed on the front cover except the Electrical Checkout Proce- dure sections which are model specific. The informa- tion in this manual will cover each version of the mod- els covered with an emphasis on the U

10、.S. (120VAC 60 Hz) version. The sections covered include General Parts Information, Circuit Theory, Specifications, Volt- age Conversion, Electrical Checkout Procedures, Ex- ploded Views (mechanical art with parts list), Printed Circuit Board Art (tracework drawings), Module Parts Lists, and Schemat

11、ics. Note that component parts with circuit board comprise a complete module. Module part numbers are always associated with a specific circuit board, although an unpopulated circuit board may be built up with different parts to create different modules. Note that Crown does not sell blank (unpopula

12、ted) circuit boards. Each of the compact audio power amplifiers are de- signed for professional or commercial use. Providing power amplification from 20Hz-20KHz with minimum distortion, they feature balanced inputs with bridged monophonic capability. Specific features vary depend- ing on model famil

13、y. Warranty Each Owners Manual contains basic policies as re- lated to the customer. In addition it should be stated that this service documentation is meant to be used only by properly trained service personnel. Because most Crown products carry a 3 Year Full Warranty (in- cluding round trip shippi

14、ng within the United States), all warranty service should be referred to the Crown Factory or Authorized Warranty Service Center. See the applicable Owners Manual for warranty details. To find the location of the nearest Authorized Service Center or obtain instructions for receiving Crown Fac- tory

15、Service please contact the Crown Technical Sup- port Group (within North America) or your Crown/ Amcron Importer (outside North America). Crown Technical Support Group Factory Service Parts Department Mailing Address: P.O. Box 1000 Elkhart, IN USA 46515-1000 Shipping Address: 57620 C.R. 105 Elkhart,

16、 IN USA 46517 Phone: (219) 294-8200 T T T T Toll Froll Froll Froll Froll Free: (800) 342-6939ee: (800) 342-6939ee: (800) 342-6939ee: (800) 342-6939ee: (800) 342-6939 Facsimile: (219) 294-8301 D-45 / D-75A Amplifier Service Manual 5 General Parts Information General Information Later sections include

17、 both mechanical and electrical parts lists for this product. The parts listed are current as of the date printed. Crown reserves the right to modify and improve its products for the benefit of its customers. Part Numbering Systems As of the printing of this manual, Crown is using two numbering syst

18、ems. The elder system always uses eight characters. The first character is a letter. Com- mon letters used are C, D, H, M, P, and Q. The second through sixth characters are numbers. The numbers build sequentially (for each prefix letter) as new parts are added to our parts inventory system. (In some

19、 cases there will be a space then a four character number after the prefix letter; the space is considered a character.) The seventh character is usually a hy- phen, though it may be a letter to indicate a revision or special note. The last character is called a check-digit, and is useful to Crown f

20、or internal tracking. Crown is in the process of converting to a new part number system. Length may vary from eight to twelve characters. There is still a letter prefix, then five num- bers. These five numbers identify a type of part. The seventh character is a hyphen. Remaining characters identify

21、the details of the type of part identified by the first part of the number. Standard and Special Parts Many smaller electrical and electronic parts used by Crown are stocked by and available from electronic supply houses. However, some electronic parts that appear to be standard are actually special

22、. A part ordered from Crown will assure an acceptable re- placement. Structural items such as modules and panels are available from Crown only. Ordering Parts When ordering parts, be sure to give the product model, and include a description and part number (CPN/DPN) from the parts listing. Price quo

23、tes are available on request. Shipment Shipment will be normally made by UPS or best other method unless you specify otherwise. Shipments are made to and from Elkhart, Indiana USA, only. Estab- lished accounts with Crown will receive shipment freight prepaid and will be billed. All others will recei

24、ve ship- ment on a C.O.D. or pre-payment (check or credit card) basis. Terms Normal terms are pre-paid. Net-30 Days applies to only those firms having pre-established accounts with Crown. If pre-paying, the order must be packed and weighed before a total bill can be established, after which an amoun

25、t due will be issued and shipment made upon receipt of pre-payment. New parts re- turned for credit are subject to a 10% re-stocking fee, and authorization from the Crown Parts Department must be obtained before returning parts for credit. Crown is not a general parts warehouse. Parts sold by the Cr

26、own Parts Department are solely for servicing Crown/Amcron products. Part prices and availability are subject to change without notice. Crown Parts Department Mailing Address: P.O. Box 1000 Elkhart, IN USA 46515-1000 Shipping Address: 57620 C.R. 105 Elkhart, IN USA 46517 Phone: (219) 294-8200 T T T

27、T Toll Froll Froll Froll Froll Free: (800) 342-6939ee: (800) 342-6939ee: (800) 342-6939ee: (800) 342-6939ee: (800) 342-6939 Facsimile: (219) 294-8301 D-45 / D-75A Amplifier Service Manual 6 Specifications Unless noted otherwise, all specifications are based on driving an 8 ohm load per channel, both

28、 channels driven. The AC supply is 120VAC 60Hz. Crown speci- fications are guaranteed through the warranty period (normally 3 years). Because our testing methods are more stringent than our published specifications, ev- ery Crown amplifier will exceed its published specifi- cations. Power Output Pow

29、er Note: Maximum average power at 1 KHz with less than 0.1% THD. D-75A 16 Ohm Stereo25W/Ch 8 Ohm Stereo40W/Ch 4 Ohm Stereo55W/Ch 16 Ohm Bridge Mono80W 8 Ohm Bridge Mono110W D-45 16 Ohm Stereo20W/Ch 8 Ohm Stereo25W/Ch 4 Ohm Stereo35W/Ch 16 Ohm Bridge Mono50W 8 Ohm Bridge Mono70W Load Impedance: Safe

30、with all types of loads. Rated for 4 to 16 ohms in Dual, and 8 to 16 ohms in Bridged Mono mode. AC Mains: 100, 120, 200, 220, and 240 VAC units are available (all voltage requirements are 10%). 50 to 400 Hz AC mains can be used with international units depending on the transformer configuration. Nor

31、th American 120 VAC, 60 Hz units are not convertible and can only be used at the specified voltage and frequency. Both units draw 15 watts or less when idle. Maximum AC power consumption is 150 watts. Performance Frequency Response: 0.1dB from 20 Hz to 20 KHz at 1 watt. Phase Response: +10 to -15 fr

32、om 20 Hz to 20 KHz at 1 watt. Signal-to-Noise Ratio: 106dB below full rated output from 20 Hz to 20 KHz at 1 watt. Total Harmonic Distortion (THD): Less than 0.001% at full rated output from 20 Hz to 400 Hz increasing lin- early to 0.05% at 20 KHz. Intermodulation Distortion (IMD): Less than 0.05% f

33、rom 0.01 to 0.25 watts; less than 0.01% from 0.25 watts to full rated output. Controlled Slew Rate: Greater than 6 volts per micro- second. (Slew rates are limited to useful levels for ul- trasonic/RF protection.) Damping Factor: Greater than 400 from DC to 400 Hz. Input Impedance: Nominally 20 K oh

34、ms balanced, and 10 K ohms unbalanced. Output Impedance: Less than 15 milliohms in series with less than 3 microhenries. Input Sensitivity: 26 dB voltage gain. Configurable for 0.775 volt sensitivity. Mechanical/Features Power Switch: A two-position front panel rotary switch. Level Controls: A deten

35、ted front panel rotary potenti- ometer for each channel used to control the output level. Dual-Mono: A dual-mono jumper located inside the amplifier. AC Line Connector: Standard three-wire grounded con- nector. Power Indicator: This orange indicator shows that the unit has been turned on. IOC Indica

36、tors: A red indicator for each channel flashes if the amplifier causes any distortion of 0.05% or more. Signal Presence Indicators (SPI): A green indicator for each channel flashes to show that there is amplifier output. Input Connectors: A balanced three-pin female Neutrik combination XLR and 1/4 i

37、nch phone connector for each channel. Output Connectors: A four-terminal barrier block (two ter- minals per channel) and stereo headphone jack. Head- phone output is unpadded and in parallel with the main outputs. Chassis Construction: Durable black finish on the steel chassis, and an aluminum front

38、 panel with Lexan over- lay specially designed to provide maximum heat con- duction and minimal weight. Cooling: Convection. Dimensions: 19 inches (48.3 cm) wide, 1.75 inches (4.45 cm) tall and 8.38 inches (21.27 cm) deep be- hind the front mounting surface. Approximate Weight: Net 10 lbs (4.53 Kg).

39、 Shipping 12 lbs (5.45 Kg). Mounting: Standard EIA 310 19-inch rack mounting. D-45 / D-75A Amplifier Service Manual 7 Circuit Theory Overview It should be noted from the start that the D-45 and the D-75A have identical circuitry except for the size of the power supply. The same schematic is used for

40、 both models. It is also important to realize that over time Crown can introduce improvements to its amplifiers. Though often changes are minor, and are made for a variety of reasons it is a good idea to see if any Tech- nical Notes have been issued on these models. This manual is up to date as of t

41、he time of writing, Novem- ber 1995. This section of the manual explains the general op- eration of the D-45 and D-75A amplifiers. Topics cov- ered include Power Supply, Balanced input stage, Er- ror amp, Signal Translator , Last Voltage Amplification stage, Bias, Output stage, Protection circuitry,

42、 IOC, and Signal Presence Indicators (SPI). Block Diagram The following discussion refers to the block diagram in figure 1. The balanced input signal is converted to an unbal- anced signal at the input stage. This unbalanced sig- nal is then routed through the volume control into the Error Amp which

43、 provides voltage amplification with extremely low distortion by means of several feedback paths, one of which is from the output stage providing distortion control from input to output. Any difference in the comparison between the input signal and out- put signal of .05% or greater will result in a

44、n Error sig- nal, and the IOC indicator will light. Next, the signal is feed into the Signal Translator. This transistor converts the signal reference from ground to the negative sup- ply, allowing greater voltage swing capabilities. The Last Voltage Amp (LVA) then recieves the signal and gives it m

45、ore voltage amplification. This is the main voltage amplification stage. The output of the LVA pro- vides the signal drive to the output stage which pro- vides the current necessary for the final output power. Figure 1: D-45, D-75A amplifier circuit block diagram (channel one only) Bal. InputSig. Tr

46、anslatorOutput Stage IOC 10V AC Line SPI Mono Switch To Ch 2 Input Op-Amp Power Supply Ch 1 Out Feed Back Loop Error Amp Last Voltage Amp Ch 1 In + - D-45 / D-75A Amplifier Service Manual 8 Circuit Theory Power Supply The power supply consists of a single power trans- former with two sets of seconda

47、ry windings which are paralled together. The AC power is then full wave rec- tified and filtered with capacitors C8 and C9. The re- sult is VCC voltages of 31VDC for the D-45, and 35VDC for the D-75A. The power supply is protected by the fuse F1 which is in series with the primary of the transformer

48、. The power indicator lamp is in series with a 27K ohm resistor and is across the primary of the transformer. The 10 volt supplies, which supply voltage to the in- tegrated circuits, are regulated by the 10 volt zener diodes D1 and D2. VCC supplies voltage to these zeners through R1 and R2. Balanced Input Stage In order to eliminate annoying noise and RF interfer- ence, a balanced input stage is incorporated into the design of the D-45 and D-75A. U100 is the b