Yorkville-Audiopro3400-pwr-sm 维修电路原理图.pdf

SERVICE MANUAL3400HIGH EFFICIENCY STEREO POWER AMPLIFIERU.S.A.Yorkville Sound Inc.4625 Witmer Industrial EstateNiagara Falls, New York14305 USAVoice: (716) 297-2920Fax: (716) 297-3689WORLD HEADQUARTERSCANADAYorkville Sound550 Granite CourtPickering, OntarioL1W-3Y8 CANADAVoice: (905) 837-8481Fax: (905) 837-8746Quality and Innovation Since 1963Printed in CanadaRadioFans.CN 收音机爱 好者资料库Manual-Service-AP3400-00-1v6.pdf1AUDIOPRO AP-3400 SERVICE MANUALM1012A “THE INPUT BOARD”The input board processes the audio signal from the input jacks to the voltage amplifier board, (M1011A).Each channel consists of a balanced gain stage, defeatable bass boost filter, and a preemphasis filter network.The balanced input, (XLR Jack) and unbalanced input (phone jack) are wired in parallel to the input of a balancedoperational amplifier, (U1). The gain of this stage is 1.6 (4dB) balanced and 1.6 (4dB) unbalanced. Resistors R1, R5along with capacitors C1 and C2 form a radio interference elimination filter.Switch S1 selects a flat or bass boosted frequency response. The bass boost filter provides a 20Hz high pass, high Qfilter response with a +4dB peak at 55Hz. The filter consists of a tee network on the input of U1A along with R9, R10,R11, C5 and C6. The gain is 1 (0dB) in the passband, (above 100Hz).Operational amplifier U3B is a high pass shelving filter with a +2dB shelf above 20KHz. This filter provides the pre-emphasis required to obtain a flat frequency response (to 20KHz) on the power amplifier output at full power.M1011A VOLTAGE AMPLIFIERS AND SYSTEM CONTROLThis board contains:Voltage amplifiers to drive the current amplifiers on the M1002A boards.The front panel volume control circuitry.The EMS control system with its associated circuits: Pre clipping and line current sensing heater circuits.Clip and activity LEDs. Driver circuitry for the amplifier disable relay (used during amplifier turn on, turn off,thermal shutdown and current limiting).Circuit Explanation:Refer to the schematic of M1011A as the sections of the circuit are explained.The audio signal enters the board from M1012A through connector MS4. The two channels are marked L and Rfor left and right. The signals are to be considered as differential sources and therefore are marked as L+, L-,R+ andR-. Since the left channel has the same topology as the right channel we will only look at the left channel.The signal (L+) at the terminal block (MS4) passes through the front panel level control (P1) and the desired levelenters the inverting input of U1.Op amp U1 is an inverting amplifier with a set gain of 2.40 (7.6dB). Built around U1 is a dual purpose circuit controlledby a voltage divider consisting of R15, R16, R17, R18, R19, R20 and R21. The voltage divider sets two referencelevels, (HDRM & CLP). Reference voltage levels vary with the voltage levels on the +/-144VDC supply rails. As theamplifier?s output is loaded, the supply rails voltage decreases and so do the reference levels.Transistors Q1, Q3 the surrounding resistors provide a pre-clipping function that tracks the supply rails through theHDRM voltage reference and clips the audio signal at approximately 11.2V pk. The clip LED indicator circuit isconnected through D1 and D2 to the output of U1, The bases of Q2 and Q4 are connected to the “CLP” referencevoltage, and when the peak output voltage of U1 (+/-Vp) is enough to forward bias the transistor junctions, Q2 or Q4will trigger the clip led circuit (Q5), and illuminate the clip LED.The audio signal on the output of U1 enters U3 through R43 and RV1. Under normal operating conditions the gain ofU3 is 1(0dB). The signal then passes through U2 to the voltage amplifier.The exclamation point within an equilatereal triangle is intended to alert the user to the presence of important operating and maintenance (servicing) instructions in the literature accompanying the appliance.Le point dexclamation lintrieur dun triangle quilatral est prvu pour alerter lutilisateur de la prsence dinstructions importantes dans la littrature accompag-nant lappareil en ce qui concerne lopration et la maintenance de cet appareil. This lightning flash with arrowhead symbol, 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.Ce symbole dclair avec tte de flche dans un triangle quilatral est prvu pour alerter lutilisateur de la prsence dun voltage dangereux non-isol proximit de lenceinte du produit qui pourrait tre dampleur suffisante pour prsenter un risque de choque lectrique.IMPORTANT SAFETY INSTRUCTIONSsafety-4v5.eps April 3/2007CAUTION: TO REDUCE THE RISK OF ELECTRICSHOCK, DO NOT REMOVE COVER (OR BACK).NO USER SERVICEABLE PARTS INSIDE.REFER SERVICING TO QUALIFIEDSERVICE PERSONNEL.FOLLOW ALL INSTRUCTIONSSUIVEZ TOUTES LES INSTRUCTIONSInstructions pertaining to a risk of fire,electric shock, or injury to a personRead Instructions: The Owners Manual should be read and understood before operation of your unit. Please, save these instruc-tions for future reference and heed all warnings. Clean only with dry cloth.Packaging: Keep the box and packaging materials, in case the unit needs to be returned for service.Warning: To reduce the risk or fire or electric shock, do not expose this apparatus to rain or moisture. Do not use this apparatus near water!Warning: When using electric products, basic precautions should always be followed, including the following:Power SourcesYour unit should be connected to a power source only of the voltage specified in the owners manual or as marked on the unit. This unit has a polarized plug. Do not use with an extension cord or receptacle unless the plug can be fully inserted. Precau-tions should be taken so that the grounding scheme on the unit is not defeated.HazardsDo not place this product on an unstable cart, stand, tripod, bracket or table. The product may fall, causing serious personal injury and serious damage to the product. Use only with cart, stand, tripod, bracket, or table recommended by the manufacturer or sold with the product. Follow the manufacturers instructions when installing the product and use mounting accessories recommended by the manufacturer.The apparatus should not be exposed to dripping or splashing water; no objects filled with liquids should be placed on the apparatus.Terminals marked with the “lightning bolt” are hazardous live; the external wiring connected to these terminals require installation by an instructed person or the use of ready made leads or cords.Ensure that proper ventilation is provided around the appliance. Do not install near any heat sources such as radiators, heat registers, stoves, or other apparatus (including amplifiers) that produce heat.No naked flame sources, such as lighted candles, should be placed on the apparatus.Power CordDo not defeat the safety purpose of the polarized or grounding-type plug. A polarized plug has two blades with one wider than the other. A grounding type plug has two blades and a third grounding prong. The wide blade or the third prong are provided for your safety. If the provided plug does not fit into your outlet, consult an electrician for replacement of the obsolete outlet. The AC supply cord should be routed so that it is unlikely that it will be damaged. If the AC supply cord is damaged DO NOT OPERATE THE UNIT.Unplug this apparatus during lightning storms or when unused for long periods of time.ServiceThe unit should be serviced only by qualified service personnel.AVIS: AFIN DE REDUIRE LES RISQUE DE CHOCELECTRIQUE, NENLEVEZ PAS LE COUVERT (OU LEPANNEAU ARRIERE) NE CONTIENT AUCUNE PIECEREPARABLE PAR LUTILISATEUR.CONSULTEZ UN TECHNICIEN QUALIFIEPOUR LENTRETIENTInstructions relatives au risque de feu,choc lectrique, ou blessures aux personnesVeuillez Lire le Manuel: Il contient des informations qui devraient tres comprises avant lopration de votre appareil. Conservez. Gardez S.V.P. ces instructions pour consultations ultrieures et observez tous les avertissements. Nettoyez seulement avec le tissu sec.Emballage: Conservez la boite au cas ou lappareil devait tre retourner pour rparation.Avertissement: Pour rduire le risque de feu ou la dcharge lectrique, nexposez pas cet appareil la pluie ou lhumidit. Nutilisez pas cet appareil prs de leau!Attention: Lors de lutilisation de produits lectrique, assurez-vous dadhrer des prcautions de bases incluant celle qui suivent:AlimentationLappareil ne doit tre branch qu une source dalimentation correspondant au voltage spcifi dans le manuel ou tel quindiqu sur lappareil. Cet appareil est quip dune prise dalimentation polarise. Ne pas utiliser cet appareil avec un cordon de raccordement moins quil soit possible dinsrer compltement les trois lames. Des prcautions doivent tres prises afin deviter que le systme de mise la terre de lappareil ne soit dsengag.RisqueNe pas placer cet appareil sur un chariot, un support, un trpied ou une table instables. Lappareil pourrait tomber et blesser quelquun ou subir des dommages importants. Utiliser seulement un chariot, un support, un trpied ou une table recommands par le fabricant ou vendus avec le produit. Suivre les instructions du fabricant pour installer lappareil et utiliser les accessoires recommands par le fabricant.Il convient de ne pas placer sur lappareil de sources de flammes nues, telles que des bougies allumes.Lappeil ne doit pas tre expos des gouttements deau ou des claboussures et quaucun objet rempli de liquide tel que des vases ne doit tre plac sur lappareil.Assurez que lappareil est fourni de la propre ventilation. Ne procdez pas linstallation prs de source de chaleur tels que radiateurs, registre de chaleur, fours ou autres appareils (incluant les amplificateurs) qui produisent de la chaleur.Les dispositifs marqus dune symbole “dclair” sont des parties dangereuses au toucher et que les cblages extrieurs connects ces dispositifs de connection extrieure doivent tre effectivs par un oprateur form ou en utilisant des cordons dj prpars.Cordon dAlimentationNe pas enlever le dispositif de scurit sur la prise polarise ou la prise avec tige de mise la masse du cordon dalimentation. Une prise polarise dispose de deux lames dont une plus large que lautre. Une prise avec tige de mise la masse dispose de deux lames en plus dune troisime tige qui connecte la masse. La lame plus large ou la tige de mise la masse est prvu pour votre scurit. La prise murale est dsute si elle nest pas conue pour accepter ce type de prise avec dispositif de scurit. Dans ce cas, contactez un lectricien pour faire remplacer la prise murale. vitez dendommager le cordon dalimentation. NUTILISEZ PAS LAPPAREIL si le cordon dalimentation est endommag.Dbranchez cet appareil durant les orages ou si inutilis pendant de longues priodes.ServiceConsultez un technicien qualifi pour lentretien de votre appareil.S2125ARadioFans.CN 收音机爱 好者资料库2VOLTAGE AMPLIFIER:The voltage amplifier amplifies the audio signal?s voltage from 4.8 volts peak (at the output of U2) to approximently97v peak which is required to drive the current amplifier board M1002A. M1002A provides the current required for the97v peak signal to drive 1200 watts into 4 ohms out of the binding posts.Before the circuit is described in detail here is a quick rundown on the signal?s path through the voltage amplifierstage. Refer to the schematic of M1011A. Lets consider that a positive going AC signal is present test point 3. Thepositive going signal will turn on the positive side of the voltage amplifier. The signal at test point 3 turns on Q12(through R40, D14 and D13). The collector of Q12 pulls down on the base of Q14, turns this transistor on further andallows a greater current to flow out of Q14?s collector. This increase in current passes through Q15 and it?s collector toemitter voltage drop decreases. The collector of Q15 now being more positive in voltage turns the base of Q18 oncausing an increase in Q18?s collector current resulting in test point 5 going positive.As the positive side of the amplifier was turning on the negative side would have been turning off. This is how testpoint 5 was able to move positive following the input signal. The reverse would hold true if a negative going signal waspresent on the input of the voltage amplifier.CIRCUIT DESCRIPTION:The voltage amplifier is a mirrored image with circuitry connected to the positive power supply rail being identical (butopposite polarity) to the circuitry connected to the negative power supply rail.For this reason we will look in detail at the positive side of the amplifier.The audio signal enters the voltage amplifier at test point 3. The signal passes through R40, D14 and D13 to the baseof Q12. Diodes D13 and D14 set up the DC bias on Q12 to approximately 0.6 mA.The first voltage gain stage consists of Q12 along with the resistor chain on its collector and the emitter resistor (R44).Transistor Q12 drives the base of Q14 through the resistor chain. A DC current of approximately 6 mA should flowthrough the collector of Q14. The voltage drop across Q14 remains constant and is derived from the voltage dropacross the voltage reference Q20, resistor R58, and the base/emitter junction of Q15. This total voltage should equalapproximately 3 VDC. Transistor Q14 is the second gain stage and its output current flows through Q15. TransistorQ15 is a common base stage with the collector driving the base of output buffer Q18.Diode D17 is a clamping diode that prevents the maximum peak of the audio signal from coming within 4V of the 144VDC rail. This is to prevent the output current amplifier (board M1002A) from going into saturation during clipping andtherefore having storage delay problems.Transistor Q18 buffers the high impedance present on the collector of Q15. The output of the buffer provides a lowoutput impedance at test point 5 and is current limited to 25mA through the clamping action of D19, D20 and D23.The signal at TP-5 drives the current amp board M1002A.DC offset on the amplifier?s output is corrected by operational amplifier U2. The DC offset forms a current throughR54, R14 and is blocked by C5 giving a DC offset correction gain of -1.The activity L.E.D. function is a simple charge pump circuit with a transistor that redirects a constant current paththrough the activity L.E.D.3SHUTDOWN CIRCUIT:The last circuit on board M1011A is the shutdown relay and its associated drive circuitry. The relay circuit has twopossible operating states.1. Amplifier on under normal operating conditions.2. Amplifier power switch has just been turned OFF/ON or the amplfier is in current limit protecting the amplifier?soutput or the amplifier has overheated.CIRCUIT DESCRIPTIONHere is how the circuit accomplishes these functions. The relay?s normally closed contacts short the output of thevoltage amplifiers to ground when the power switch is off. When the power switch