Classe-CAV75-pwr-sm维修电路原理图.pdf

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1、PRO-SVR_LEGACY Page 1 of 13 Date:August 20, 2007 Model Number: CAV-75 Class Audio Inc.Subject:Service manual Class Audio, Inc. 5070 Franois Cusson Lachine, Qubec Canada H8T1B3, RadioFans.CN 收音机爱 好者资料库PRO-SVR_LEGACY Page 2 of 13 Table of ContentsIntroduction 3Important Notes on Servicing 3Ordering Re

2、placement Parts 3Block Diagrams 4Start up Procedure 5Protection Modes and Indicators 6Troubleshooting Guide 7Output Transistors Testing and Replacement 8Calibrations and Adjustments 9Parts List 10Updates 11Fuses 12Voltage Change 12Remote Interface Information 13Schematics 14The contents of this docu

3、ment as well as the files associated with it contain confidential information that is proprietary to Class Audio Incorporated and are intended solely for the purpose of servicing product. No part of its contents may be used, copied, disclosed, or conveyed to any party in any manner whatsoever withou

4、t prior written permission from Class Audio Incorporated. RadioFans.CN 收音机爱 好者资料库PRO-SVR_LEGACY Page 3 of 13 IntroductionPlease read this manual carefully before commencing servicing! Only qualified and authorized personnel should attempt to service this product. The lightning flash with arrowhead s

5、ymbol, within an equilateral triangle, is intended to alert the user to the presence of uninsulated dangerous voltage within the products enclosure that may be of sufficient magnitude to constitute a risk of electric shock to persons. The exclamation point within an equilateral triangle is intended

6、to alert the user to the presence of important operating and maintenance (servicing) instructions. Class has a global product support network. For product assistance or to order replacement parts please contact your nearest service center always quoting the unit serial number. North America Phone: (

7、978) 664-2870 E-mail: EuropePhone: 44 (0) 1903 221 700 E-mail: AsiaPhone: (852) 2790 8903 E-mail: classebwgroup.hkRest of the World Phone: (514) 636-6384 E-mail: Important Notes on Servicing 1.ALWAYS observe ESD precautions when handling electronic modules or PCBAs. 2.NEVER exchange boards with a di

8、fferent revision number, unless authorized by Class. 3.ALWAYS use Class original replacement parts. The use of generic parts may void the warranty of the unit. Ordering Replacement Parts There may be a delay in processing incomplete requests. Please be sure to include all required information. Remem

9、ber to quote the serial number of the unit on all replacement part orders and the Class order number when returning defective parts for credit. PRO-SVR_LEGACY Page 4 of 13 Block diagramsPRO-SVR_LEGACY Page 5 of 13 Start Up ProcedureWhen receiving a unit, an assiduous visual inspection must be perfor

10、med. Do not connect the unit without analysing the symptoms reported by the customer and the results of the inspection. Using the troubleshooting guide, find the problem and proceed to the repair. Once this step is done, follow these steps, known as the start-up procedure, to ensure that everything

11、in the unit is in working condition. 1. Proceed with a post repair visual inspection. Take the time to check if every wire is reconnected properly, every screw is bolted on, no soldering and/or metal residues lying in the unit, every fuse has been replaced, etc. 2. Turn the bias trimpots, counter cl

12、ockwise for channels 2, 4, 6 and clockwise for channels 1, 3, 5, until a click is heard. 3. Since there is no soft-start sequence of the CAV-75, it is impossible to us a bypass to perform a slow start up.4. Connect Main supply, and turn on the unit. 5. If one or more supply are not within specificat

13、ions, return to the troubleshooting guide. 6. If every supply is within specifications, report to calibration and adjusments to adjust bias and DC offset. Note that bias can be adjusted to 14mV, and the following tests can be performed before the unit is send to the burn-in bench for a 24 hours warm

14、-up. 7. Connect the unit to a load, and to a source using single ended inputs. 8. Perform a test with a 200Hz, a 2kHz and a 20kHz tone, both sinus wave and square wave. Check the output with a oscilloscope, on 4 ohms and 8 ohms loads. Take special cares about oscillation and phase correlation betwee

15、n channels. 9. Connect the unit to a small speaker, and short the input. Check for any noise. 10. Put the unit on a burn-in bench, and let it sit for 24 hours, then readjust bias. Let the unit on the burn-in bench for another 72 hours. 11. Redo steps 7 to 11 before shipping to the customer. PRO-SVR_

16、LEGACY Page 6 of 13 Protection Modes and IndicatorsThe front LED shows the status of the amplifier (ON or OFF). Unlike other Class amplifiers, when starting up a CAV75, the front LED will not show a flashing pattern, since there is no soft start sequence. The only protection available on a CAV75 con

17、sists of rail and mosfet fuses. If there is a fault, one or more fuses will blow, showing a faulty component. The technician will first need to identify and cure the cause of failure (please report to troubleshooting guide). When the cause has been identified, disconnect the unit from the system inc

18、luding the AC power. Remove the top cover and look for damaged or burned components. If no other components than the fuses appear to be damaged, the technician can then replace the broken fuses with the same value and rating (please report to fuses section). The fuses are located on the capacitor bo

19、ard. When replacing fuses, please make sure that the fuse holder are holding the fuses very tightly. A loose fuse holder can translate into distortion on top of the signal. PRO-SVR_LEGACY Page 7 of 13 Troubleshooting GuideSymptom Possible cause Unit won t turn on Check connections; Check fuses; Chec

20、k relays; Check power supply circuits (positive rail, negative rail, Mosfet supply). Smoked and/or burned components Check for short between components and ground; Check output transistors; Check output relays; Check power supply circuits (positive rail, negative rail, Mosfet supply). Blown fuses Ch

21、eck for short between fuse and ground; Check power supply circuits (positive rail, negative rail, Mosfet supply). No output Check connexions; Check output relays; Check power supply circuits (positive rail, negative rail, Mosfet supply);Check output transistors. Unit turn into protection Check for s

22、moked and/or burned components; Check power supply circuits (positive rail, negative rail, Mosfet supply);Check source and load; Check protection circuit; Check sensor wires between sensor PCB and control PCB; Check outputs transistors and Mosfet drivers. Excessive buzz and/or hum Check electrical l

23、ines; Check for a ground loop in the system. Oscillation Check source; Check capacitors on main board; Check 4.7? resistor. Intermittent signal Check connections; Replace shield wires. PRO-SVR_LEGACY Page 8 of 13 Output Transistors Testing and ReplacementPLEASE NOTE THAT THESE TESTS ARE ONLY EFFECTI

24、VE ON BIPOLAR TRANSISTORS. DO NOT PERFORM THESE TESTS ON MOSFET DEVICES, AS THEY ARE LIKELY TO BECOME SHORT DURING THE TEST.You should check all pin combinaisons, as there is a chance that only one side of the transistor is short. When replacing outputs transistors, the technician should first disco

25、nnect both outputs and main board to check if the blown outputs were caused by a faulty component on the amplifier s base. Blown output transistors should be replaced by kits, not individually. These kits contains matched transistors for both rails of one channel. When replacing blown output transis

26、tors, you must also replace positive and negative Mosfet drivers and bias transistor. Carefully inspect 4.7? resistor and replace if necessary. Replace any burnt component or board. Pins : 1 Base 2 Collector 3 Emitter You should have these results, if the transistor is good. 2SC3263 (NPN) Positive l

27、ead Negative lead Result B C Conductive B E Conductive C B Infinite C E Infinite E B Infinite E C Infinite 2SA1294 (PNP) Positive lead Negative lead Result B C Infinite B E Infinite C B Conductive C E Infinite E B Conductive E C Infinite PRO-SVR_LEGACY Page 9 of 13 Calibrations and AdjustmentsBias a

28、djustment: Note: Bias adjustment should be made without any load connected to the amplifier s output, and no signal connected to the amplifier s input. 1. Since it is impossible to connect a multimeter to both emitter s resistors in order to measure and adjust bias without disassembling the heatsink

29、 from the chassis, we provided a test point to ease the bias procedure. It is located near the bias trimpot. 2. Connect the positive probe of a millivoltmeter to the test point and the negative probe to the positive speaker post of the channel to be adjusted. 3. Turn channel 2, 4, 6 trimpots counter

30、clockwise and channel 1, 3, 5 trimpots clockwise until it reaches 0?. A click should be heard. 4. Turn on amplifier, and let it warm up for 15 minutes on idle. 5. Adjust trimpot to get a 14mV reading. 6. Let the amplifier warm up for a 24 hours period with signal and load. 7. Remove signal and load,

31、 and reconnect the multimeter. 8. Readjust to 20mV. DC offset: Note: DC offset adjustment should be made without any load connected to the amplifier s output, and no signal connected to the amplifier s input. On these units, DC offset can t be adjusted. Measure DC offset using a voltmeter connected

32、to the output posts, scale setted to mV. DC offset should be less than 10mV. PRO-SVR_LEGACY Page 10 of 13 Parts ListThis is not a detailed part list. It is a list of major chassis parts and PCBs. If you need to order a specific part, please contact Classe Audio with the part location, PCB number, an

33、d model and serial number of the unit. If you need a complete PCB, please replace the (x) in the Classe part number with the revision number printed on the board. Parts Description Classe part number B01CX Complete PCB, power switch B01CXR(x) B01GX Complete PCB, filter B01GXR(x) B0D3X Complete PCB,

34、capacitor B0D3XR(x) B0D1X Complete PCB, heatsink B0D1XR(x) B0D4X Complete PCB, supply B0D4XR(x) B0D2X Complete PCB, amplifier B0D2XR(x) B01DX Complete PCB, remote B01DXR(x) PRO-SVR_LEGACY Page 11 of 13 Updates1. On board B0D1X (3 PCBs), replace R110 and R210 with Classe part number A211-1308. PRO-SV

35、R_LEGACY Page 12 of 13 FusesEXTRA PRECAUTIONS SHOULD BE TAKEN WHEN REPAIRING, MODIFYING, ORTROUBLESHOOTING IN THE POWER SUPPLY AREA. UNIT MUST BE DISCONNECTFROM MAIN SOURCE AND CAPACITORS MUST BE DISCHARGED USING A 100W INCANDESCENT BULB. WHEN REPLACING FUSES, PLEASE MAKE SURE THAT THE FUSE HOLDERS

36、ARE HOLDING THE FUSES VERY TIGHTLY. A LOOSE FUSE HOLDER CAN TRANSLATE INTO DISTORTION ON TOP OF THE SIGNAL. Main fuses: For 100 120v units: 6A slo-blo, Classe part number MDL-6A For 220 240v units: 4A slo-blo, Classe part number MDL-4A The main fuse is located at the back of the unit, on the rear pa

37、nel. Control board fuse: 0.50A, Classe part number 225.500 The control board fuse is located on top of the supply board (B0D4X) Mosfet fuses: 0.75A, Classe part number 225.750 The Mosfet fuses are located on top of the capacitors board (B0D3X) Rail fuses: 3.15A, Classe part number GDB-3.15A The rail

38、 fuses are located on top of the capacitors board (B0D3X) Voltage ChangeEXTRA PRECAUTIONS SHOULD BE TAKEN WHEN REPAIRING, MODIFYING,ORTROUBLESHOOTING IN THE POWER SUPPLY AREA. UNIT MUST BE DISCONNECTFROM MAIN SOURCE AND CAPACITORS MUST BE DISCHARGED USING A 100W INCANDESCENT BULB. 1. Set the jumper

39、position according to the table below. 2. Replace the varistor, according to new line voltage, following Classe s recommendations. If varistor is not available, remove old varistor and leave it empty. Jumper positions, main transformer Mains Jumper 1 Jumper 2 Jumper 3 Varistor 100VAC A E F 221 120VA

40、C A C D 221 220VAC B E - 391 / 441 240VAC B D - 391 / 441 Jumpers, auxiliary transformer Mains Position 1 Position 2 Position 3 Position 4 Position 5 100/120VAC In Out Out Out In 220/240VAC Out Out In Out Out PRO-SVR_LEGACY Page 13 of 13 Remote Interface InformationThe CAV75 can be turned on or off using an simple interface connected to the Remote jack, located at the back of the unit.