StageAccompany-Bluebox-spk-sm 维修电路原理图.pdf

This manual contains confidential information.An farm of du lication is rohibited!RadioFans.CN 收音机爱 好者资料库BLUE BOXSERVICE MANUAL1 Safety and warranty1.1 Safety-Warninglnside the PMS 5000 amplifier module, AC voltages up to 240 V maybe present!-Connection to the mains voltageThe PMS 5000 amplifier module chassis is connected to ground bythe grounding conductor in the power cord. To avoid electricalshock, plug the power cord into a properly wired receptacle. Whenthis ground connection is not present or interrupted, allaccessible parts of the amplifier can cause an electrical shock.-FusesTo avoid fire hazard, only replace fuses by the same type andvalue.-MaintainanceDo not perform internal maintainance or adjustments unless thereis someone present, capable of rendering first aid andreanimation.Try to perform all service works with mains power off. Removemains connector to be sure that no internal voltages are present.1.2 WarrantySUMMARYStage Accompany warrants to the original commercial purchaser ofeach new Stage Accompany product, from the date of purchase by theoriginal purchaser until the end of the warranty period, that theproduct is free of defects in materials or workmanship.WARRANTY PERIODwarranty period on all Stage Accompany products is five yearsthe date of the first consumer purchase. with the exception of:all electrical products: three years trom the date of thefirst consumer purchase;cone assemblies in the loudspeaker and diaphragms in theCompact Drivers: one year trom the date of the first consumerpurchase;Thetrom-page:date:issue:03-05-19891RadioFans.CN 收音机爱 好者资料库BLUE BOXSERVICE MANUALmovable parts, such as castors, locks, handles, hinges, fans,etc: oe year trom the date of the first consumer purchase:computers and associated peripherals: six months trom thedate of the first consumer purchase.-HOW TO VALIDATE THE WARRANTYTo validate warranty, fill out the enclosed warranty card andreturn it to Stage Accompany within ten days of the purchase date.The purchaser must always keep the original billof sale toestablish the date of purchase.ITEMS EXCLUDED FROM WARRANTYAppeal on warranty will be voided in case:- of defects caused by influence from the outside, accident,misuse, neglect or influence of water;- the serial number on the warranty and/or product has beendefaced, altered or removed;- of damage due to shipment;- of damage resulting from neglection of instructions listed inthe user manual;- of damage caused by incorrect, abnormal or abuse duringdelivery;- the unit has been repaired (or shows signs of repair) bysomeone not authorised by Stage Accompany;- if the warranty registration card has not been returned toStage Accompany within 10 days of purchase;- the original billof sale can not be presented wheneverwarranty service is required;WHAT WE WILL DOShipment of the product to a Stage Accompany dealer is at the riskand responsibility of the customer.Stage Accompany will par all labour and material expenses for allrepairs covered by this warranty. Stage Accompany will not par theoost of shipment to the Stage Accompany dealer or to the factory.However Stage Accompany will par the return shipping charges ifrepairs are covered by the warranty.page: 3date: 03-05-1989issue: 1BLUE BOXSERVICE MANUALCAUTIONWarranty work can only be performed at our authorised servicecenters or at our factory. Every repair or attempted repair by a nonauthorised party will void the warranty.Stage Accompany reserves the right to alter specifications withoutprior notice.page: 4date: 03-05-1989issue: 1BLUE BOXSERVICE MANtJAL2 Description of the Blue BoxThe Blue Box is a microprocessor controlled, activ4system, consisting of:SA 4525 enclosure,SA 8525 high frequency driver,SA 2527 horn,SA 1503 low frequency driver andPMS 5000 amplifier module.The system comprises the following features:All the electronic functions are monitored and controlled by themicroprocessor. External control is possible through SAnet.&.11-tuil rangeThe blue box contains 2 loudspea.bandwidth. Extra tweeters or subwo-nlgn OUtpUtThe Blue Box is ca120 dB continuousamplifiers are applautomatic levelier- - .-A DU1!t 1n m1croprocessoutput within the safeVCAs are involved!Ihe Input is electronically balanced (switchable totor excellent hum and noise rejection and optimalPhase is switchable to inverted.-date:L iSSUE03-05-19891issue.loudspeakerspeakers, covering the entire audiosubwoofers are not needed.orisa sound pressure level1 meter. Seperate pokeeps the avelloudspeakers. BLUE BOXSERVICE MANUAL3 Taking the Blue Box apartThe Blue Box can be taken apart in two wars.- Access to the electronics can be obtained by removingthe amplifier module- The loudspeakers can be taken outIn bath cases, be sure that the mains plug is removed from thereceptacle.The best war to dismount the amplifier module is shown in figure 1.Place the Blue Box on its wheels and open the flightcase. Remove thelid and place the blue box on its speaker panel. Be sure the surfaceis flat!Remove the balts that attache the actual Blue Box to its flightcase;one in every horizontally mounted handle.Next remove the flightcase trom the box just by pulling it off theBlue Box enclosure.Fig 1The module is attached to the chassis with 8 bolts, 4 on each side.Remove these bolts and use the handles of the module to lift themodule approx. 20 cm out of the enclosure. Disconnect theloudspeaker connectors and the flat cable.Now the module is free of connections and can be fully pulled out ofthe enclosure.date: 03-05-1989issue: 1Removing the amplifier moduleBLUE BOXSERVICE MANUALTo remove the loudspeakers (fig 2), place the Blue Box on its back.Remove the lid of the flightcase,remove the foam front (by pulling it of gently) andremove the mounting bolts of the speaker or driver rou want toreplace.Now the loudspeaker can be pulled out. In case the speaker isjammed, use a lever (a screwdriver for example).Disconnect the wires from the loudspeakers terminals.Do not use the Blue Box tor sound reinforcement purposes if one ofthe loudspeakers is removed!Before re-assembling, connect the red and yellow wires to the redterminal and the black and white wires to the black terminal.IFig. 2 Frontal viewdate: 03-05-1989issue: 1BLUE BOXSERVICE MANUAL5 Basic operation of the electronicsThis chapter describes some of the key circuits of the PMS 5000. Thecomplete circuit drawings can be found on page 16 to 29.5.1 The analog boardThe analog board contains the electronics for the input amplifier, arumble filter, the crossover, the amplifier attenuators and theRMS/peak to DC converters.The inputamplifier.The amplifiertrimmed with TR1. SeeThe input impedance isFig 3The input is equiped with two relays. Rell reverses the inputpolarity while Rel2 switches to the unbalanced input configuration.Af ter debalancing the input, low frequency rumble is removed with a24 dB/oct bessel filter at 23 Hz (IC2).IC3 and IC4 split the input signal into high and low frequencies.The circuit around IC3 is a 24 dB/oct high pass Bessel filter andthe circuit around IC4 a 24 dB/act low pass Bessel filter.The amplitude of each of the two signals are controlled by IC7 andIC8. These are digitally controlled attenuators (fig 4).page:date:issue:1003-05-19891differentialstraightforwardisopampaamplifierprovides3 dB gain. Common mode rejection can be36 tor the exact adjustment procedure.over both input legs.tor apage30 kaInput amplifierBLUE BOXSERVICE MANUALFig 4The digital code presented to D7.DOattenuation and given by the formula:where n is the decimal value of the digital code.The analog board also contains 6 electronic rectifiers. Four ofthese are peak to DC converters, the other two RMS to DC converters.The pur pose of these rectifiers is to pass the amplitude informationon the input and output voltages to the microprocessor.The basic configurations of the two convertersare shown in fig. 5.In each converter the input signal is double-sided rectified.The peak rectifier (upper circuit) stores the information through adiode in a capacitor (instant attack, slow decay).The RMS rectifier (lower circuit) slowly charges and discharges acapacitor in the negative feedback loop of an opamp.1103-05-19891page:date:issue:Digital attenuatordetermines the level ofA - 20 * log 256BLUE BOXSERVICE MANUALHAJ1a.rrPJrFig 5 electronic rectifiers5.2 The digital boardThe digital board contains a microprocessor circuit, a multiplexer,an AD converter, the SAnet driver and interface electronics fordisplays and buttons.The processor circuit (see page 20) contains an Intel 8344 uP, anaddress bus decoder (IC20), a 256K EPROM (IC21) and a 8K RAM (IC22).IC25 is a watchdog that disables the write procedure tor the RAMin case the power supply is running down.The remaining part of the digital circuit is found at page 21.The AD converter is built around IC15, IC16, IC17 and IC18.IC17-C and IC17-D are buffers tor the temperature sensors.IC15 is an analog multiplexer which selects the source that has tobe converted. Possible sources are:hot input voltage (dc in 1)cold input voltage (dc in 2)high frequency peak output level (dc hf peak)low frequency peak output level (dc lf peak)high frequency rms output level (dc hf rms)low frequency rms output level (dc lf rms)high frequency amplifier temperature (hf temp)low frequency amplifier temperature (lf temp)high frequency amplifier dc (dc high)low frequency amplifier dc (dc low)-page: 12date: 03-05-1989issue: 1ICI-fPEAKI;11-8BLUE BOXSERV I CE MANUALThe derived values are used to calculate output power, temperature,signal present etc.The actual convers ion takes place in IC16. In conjunction with IC17-B it produces a DC voltage which is compared to the DC value of thesource (selected by IC15). Comparator IC18 telIs the processorwhich voltage is higher.In 8 steps the microprocessor tries to make the output voltage ofIC17-B as close as possible to that of IC17-A (successiveapproximation) and at that time the bit value of IC16 represents thedigital value of the source voltage.ICl2 is the SAnet interface. This is a single chip RS422 driver.ICl. .IC3 are the display drivers, IC4.IC7 drive LEDs andrelays. IC9 transfers the button information to the data bus.5.3 The preamp boardThe preamp board contains the electronics to drive and correct thepower amplifier. The basic electronics of the poweramp driver areshown in figure 6.Fig 6page:date:issue:1303-05-19891drivercircuitBLUE BOXSERVICE MANUALT14 forms a current source together with R17 and ZDl. The collectorcurrent is ! 12 mA. This source provides drain current for the dualfet Tl.The input of the amplifier is connected to the gate of the leftfet, the feedback network to the gate of the right one. In a steadysituation both input and feedback voltages are CV so both the gate-drain voltages are equal. The current of T14 will be equallydivided over the two fets, so 11 - 12 - 6 mA.11 passes a current mirror composed with R8, D3 and T7.12 passes two current mirrors, one composed with D3, R9, and T6 andthe other with T11 and T12.In a steady situation 11 - 12 so all current pushed out of T7 ispulled into T12 and both the drive currents will be zero.With a rising input voltage, 11 becomes larger than 12, and not allthe current produced by T7 can be pulled into T12. The residualcurrent will be pushed into the power amplifier as drive current.With a negative input voltage, 12 is larger than 11 and drivecurrent will be pulled out of the power amplifier.DC stability is achieved by the circuit around IC1. To detect DCoffset, the power amplifiers output signal is integrated and fedinto the feedback loop.5.4 The poweramp boardFig. 7 shows the basic setup of the power amplifier.-BOV / .,.Figpage; .L6%date: 03-05-1989issue: 1power amplifierBLUE BOXSERV I CE MANUALThe driver circuit provides two signaIs, drive + and drive -. Thepositive drive current is boosted by T6 and T7 and fed to the NPNpower transistors T12.T14. The negative drive current is boosted byT5 and T8 and fed to T9.T11.T2 is set as a constant voltage source and provides the biascurrent tor the amplifier.Current limiting is handled by T3 and T4. When the current drawntrom the amplifier rises, the voltage across R26 and R27 rises too.As soon as this voltage reaches a value of ! 0.65 V, T3 and T4 startto conduct and limit the drive current tor the power stage. Currentlimiting is depending on the output voltage. At 0 V output themaximum current is ! 3 A rising to ! 12 A at 50 V.The regulated power supply board5.5The regulated power supply provides 6 different low power voltagestor both the preamplifiers, all relays and the digital circuit.First there are two 80 V voltages to feed the power amplifiersdriver circuits.Fig 8 high voltage regulatorIn this circuit (fig 8) T5 is the regulating transistor. lts baseis fed by a current source built around Tl, R6, Dl and D2. The basecurrent is regulated by T8 which senses the output voltage throughVAl. With VRl the output voltage can be set. Current protection isarranged with T7. With increasing output current, the voltage dropacross R8 increases and T7 starts deflecting T5s base current.The negative 86 V supply is built in exactly the same war.The 18 V supplies are straightforward, consisting of two integratedcircuits.The 5 V digital supply is extended with transistor T14, allowinglarger currents. The unregulated voltage (10 V) is used as relaysupply.page:date:issue:1503-05-19891BLUE BOXSERV I CE MANUAL5.6 The high power supply boardBoth power amplifiers share a common power supply which delivers 4different voltages: two high power 85 V voltages tor the amplifierspower stage and two low power 90 V voltages tor the drivertransistors.The high power voltages are rectified by a high power rectifierbridge which, tor dissipation reasons, is mounted on the chassis.The energy is stored in two 22 mF / 100 V capacitors.The low power voltages are on board rectified and the filtercapacitors are placed on top of the high power voltages.All capacitors are discharged by resistors when the power has beenswitched off.The power supply board also contains a relay that connects the mainsvoltage to the primary windings of the transformer.1603-05-19891page:date:issue:analog boardDAc:.e11PAGG 22 preamp board!J d$ .cm I ti:) I 0+-CE - I tI)QW ( -*-1 l _I !J- -IIIm-man- () .cm) -(mD- I 9f:! I aD blbl IJ W -!J- I Sf:! .I 1n:J1=J- IJ -JJ-ill- ill -=J- j -=-Kj- -cm-.amJ. mij-I aT:! I .:E.r:mJ. r-;-1 I Ef:! I-cm- 0 I i i:) I I i:) -b -cm-CE :Em 0 I iN:) I 80$00 !J$-cmD- -CmJ- 1s:J) :R:J-r;1 -rm- I s:J I -CE- 0wrnH j w CE:J-w 0 0 0Q)OdP4rodOQ).Q.+ror-fr-fP4tQOP4Q)f/J-DrJui!.Cl.miII .I 6l!m!:.p,p,f/JHQ)0p,Ca.p11(,2:;jaa11MP.,iD,i,i,i,iD,i :J:JMId0,qMPtPt:J00 .Q) ,1) .!)0 Pta.:. ll .Q Di !.I I!I cdH110ot)Q)dQ)11o-i.! tII!I0wBLUE BOXSERV I CE MANUAL7 Basic operation of the softwarechapter explainsis touched or aThisbuttonDiSPlay selectlWith this button, the contents of the 7 segment displays can beselected. There are 4 possible selections:input level (attenuation in dB), i