Stax-DA80-pwr-sm 维修电路原理图.pdf

This manual is a guide to adjustmentmethods, diagrams and parts list forDA-80 and DA-80M.OUTLINE OF CIRCUITRY2HANDLING INSTRUCTION3INTERNAL VIEW4ADJUSTMENT5POWER LAMP REPLACEMENT6TROUBLESHOOTING GUIDE7DA-80 P.C.B.8DA-80 P.C.B. PARTS LIST9DA-80M P.C.B.10DA-80M P.C.B. PARTS LIST11DA-80/DA-80M PARTS LIST 12DA-80 SCHEMATIC DIAGRAM . . . 13DA-80M SCHEMATIC DIAGRAM . . 15SPECIFICATIONS 17RadioFans.CN 收音机爱 好者资料库(9(251070201 0202 Q203 0204110010Attenuafor(l (Differential (3, Amp08102Bias(4)Constant Current CircuitInput Jack0Short CircuitP ttOverheat ProtectorDC Pr rector(8)NFB CircuitOutput Tarminal0205 0206 0207 02080109PNP Darlington Power AmpSUMMARY OF CIRCUITRYThe input is fed, via an attenuator, tothe gate of the first stage dual FETdifferential amplifier (3). The diodeconnected between the two gates is theprotective circuit for input overloads(1).The NFB signal (8) is applied to thegate shown. The dual FET differentialamplifier functions under ideal condi-tions due to the connection of theconstant current supply (4) to thecommon source.The current is reversed in the currentmirror circuit (2), driving Q110 in thecascade amplifier (5) and 0108, whichDA-80form the push-pull configuration, atconstant current. A pair of transistorswith common bases and symmetricalemitters are enclosed to the same canin the current mirror circuit. This en-sures that the current flowing in eachtransistor is the same, independent ofthe ambient temperature. Q110 andQ108 are cascade connected, consistingof transistors with extremely good highfrequency characteristics and equiva-lent characteristics.The bias circuit (6) gives the optimumbias as set by VR102, passes throughthe short-circuit protector (7), thenthrough Q107, 0109, the drive-stagetransistors for the Darlington poweramplifier (9) (10), then to the powertransistors Q201-Q204, and Q2050208, of the Darlington-connectedpower output stage. The configurationadopted for the Darlington power am-plifier has NPN (9) and PNP (10) tran-sistors in a fully complementary single-ended push-pull class A output stage.The circuitry has ample stability forclass A DC amplifier operation, withall possible circuit elements that couldcause degradation of sound qualityeliminated.AIDCurrent Mirror(2)AttenuatorOverload ProtectorInput JackDifferentialAmp0NPN Darlington Power Amp(51(90107011002010202.0fibsV0108Short CircuitEfProtectorOutput Tarminal(7)0VRI020)Bias02030209Cir01090 0PNPDarlington Pow r Ampv_Constant Current Circuit(8IOverheatt ProtectorTransformerDC Protector,-00GDC Power Supply+Vn,308)Vcf1(30V)DC Power SupplyC+V+40V)(Vr(40V)L/R INDEPENDENTPOWER SUPPLYINDICATIONSIGNAL CIRCUITSINGLE CHANNELDC Power SupplyDC Power Supple+Vcc1(+30V).-n( 30V)4V,f(*4001V ( 40V)DA-80M Current MirroCascade AmpNPN Darlington PowerPower AmpVoltage SelectorPoe rTransfor me oC +V (+37V)VI,37V) +VGAL-37V)Vf( 37V) DC Power Supply -. 0ec DC Power Supply 2RadioFans.CN 收音机爱 好者资料库240Vr r 117VIDLING INSTRUCTION(1)Location in useThis amplifier features class-A opera-tion, and special care should be takenwith respect to heat radiation. Avoidlocations exposed to direct sunlight,and place the unit, as far as possible,where there is a good circulation of air.Leave a clearance of at least 5 cm (2)above the amplifier. Also you shouldavoid places where dust is liable to beattracted.(2)Protective circuitsFour different kinds of protective cir-cuit are used to protect either the am-plifier or the speakers from damage orloss.1.Overload (input) protection: Theinput needed for maximum outputis 0.89 V. Should this reach 50 V,a clip circuit operates to preventthe amp. from being driven to fulloutput.2.PC limiter: This circuit limits thecurrent which flows through theoutput transistors to prevent themfrom being destroyed by the ex-tremely large current which wouldotherwise flow if the speakerterminals were short-circuited.3.Temperature protection: This cir-cult was designed to cut off theelectrical power supply to theamplifier as soon as exceptionallyhigh temperatures are reached. Itprevents the amp. from beingdamaged by rises in the ambienttemperature.4.Speaker protection: The speakerswill be protected from directcurrent signals greater than 5 Vappearing at the amplifier outputterminals in the face of directcurrent signals from the pream-plifier or from switching tran-sient noise. Protection is by cuttingoff the amp. electrical power sup-ply, and is effective even if theamp. itself is damaged.The above protective circuits builtinto the amplifier provide protec-tion against the most unlikelyeventualities, but you should takecare to use the amp. so that theprotective circuits are not causedto operate.If, for the causes detailed in 3 and4, the protective circuits cut offthe electrical power supply, switchthe amplifier off, determine thecause, and remove it before switch-ing the electrical power on again.If the protective circuit functionsin the same way again, cuttingoff the power a second time, pleaseread the TROUBLESHOOTINGGUIDE on the 7 page.(3)When using condenser-type speak-ersSince condenser-type (or electrostatic)speakers only have a DC impedance ofthe order of one ohm, near-DC signalsarising from eccentric or warped re-cords, or from external vibration, willcause the short-circuit protection tooperate, which will be heard as a click-ing or popping noise. If this situationshould arise, you should insert a oneor two-ohm resistor (rated 30 Watts)between the speaker and the amplifieroutput terminal as shown, and set theAC/DC switch to AC.(4)When using the DA-80/80M as themid- or high-frequency amplifier ina multi-amplifier configurationWhen the DA-80/80M is used for themid/high frequency amplifier, thechannel divider cuts out the low fre-quency component of the signal, sothat there is no possibility of DC orother very low frequency signal of veryhigh amplitude being applied to thespeakers. The possibility does remain,however, of the speakers being dam-aged by the switching noise from thechannel divider or by mistakenly pull-ing out an input jack plug. The AC/DCswitch should therefore be set to AC,and a non-polar capacitor of 10F in-serted in the case of driving a tweeter,and of 100 tF for a squawker.(5)MeasurementsThis amplifier boasts extremely highquality circuitry, and if meaningfulmeasurements are to be taken of itsexceptionally good performance, onlycorrespondingly high quality measur-ing instruments and sophisticatedmeasuring techniques should be used.(6)OthersDA-80*The AC Outlets are not linked to theamplifier power switch.*There are two models of the DA-80,one intended for 100117V operationand the other for 200230 V opera-tion. In both models the switch forselection of the actual operating volt-age to be used is to be found on theunderside of the amplifier.100V-108V aria109V-117V ariaTo comply with the voltage wherethis equipment is used, this platehas to be removed and re-set afterswitched to the required voltage.A2 i oV 2 0 V ariaDA-80MA choice of mains supply voltages forthe DA-80M is given by the voltageselector under the chassis. This offersa choice of 100V, 117V, 220V, and240V. If you need to change the oper-ating voltage, first remove the protec-tive metal device, and then set thearrow so that it points to the voltageclosest to that which you will use.O200V-2 I uV aria3UU0 0 0 0ui0000o0oP.C.B.(0890/4300)Power transformerOff-set voltage adjustment(VR101)PB-100/iO4(Assy No.6890/4100 1)Idle current adjustment(VR102)uU uail121 12171INTERNAL VIEWDA-80=LILJ0NVAtglic,00IINI1IIINII0:Itttx0rr.-rn77UOff-set voltage adjustment(VR101)PB-100/i02(Assy No.6890/2100 1)Idle current adjustment(VR102)P.C.B.(0890/2300)Power transformerElPB-200/i02(Assy No.6890/2200)DA-80MPB-200/iO4(Assy No.6890/4200)4noIdle Current AdjustmentIdlecurrentadjustment(VR102)11 Volt meterOff-set Voltage AdjustmentVolt meteroff-setadjustment(VR101)ADJUSTMENTDA-80*Idle Current Adjustment1.Switch the voltmeter range over toDC 0.5V.2.Switch the power on and exem-plifyingly measure the voltage ofR201 at the both ends. Thenadjust VR102 to make this voltage400mV40mV.3.30 minutes later, measure thevoltage of R201 at the both endsand readjust VR102 to make thisvoltage 350mV35mV.*Off-set Voltage Adjustment(To be performed after completingthe idle current adjustment)1.Leave the voltmeter range at 0.5V.2.Connect the voltmeter to the out-put terminals, and adjust VR101 toreduce the voltage to OV. Thenswitch the voltmeter over to the0.25V range, and fine adjust untila OV reading is obtained.3.Measure again 30 minutes later, fineadjusting to OV if necessary.The above procedure refers to theadjustment of the one channel only.The other channel is also adjusted bythe same procedure.DA-80M*Idle Current Adjustment1.Switch the voltmeter range over to0.5V.2.Switch the power on and exem-plifyingly measure the voltage ofR201 at the both ends. Thenadjust VR102 to make this voltage250mV25mV.3.30 minutes later, measure thevoltage of R201 at the both endsand readjust VR102 to makethis voltage 230mV23mV.*Off-set Voltage Adjustment(To be performed after completingthe idle current adjustment)1.Leave the voltmeter range at 0.5V.2.Connect the voltmeter to the out-put terminals, and adjust VR101 toreduce the voltage to OV. Thenswitch the voltmeter over to the0.25V range, and fine adjust untila OV reading is obtained.3.Measure again 30 minutes later, fineadjusting to OV if necessary.5This will be better to cover withrubber tube.POWER LAMP REPLACEMENT1. Hold concave part of the whiteplastic cover firmly with nailsleaving the power switch off andpull inside to detach the cover.2. Hold the lamp lightly with aplier or any else and pull inside toremove.3.Push-into a fresh lamp with fingers.4.Place the cover back as was before.6TROUBLESHOOTING GUIDEProblem 1Soon after the powerswitch is turned on,illumination lamp and thepilot lamp fail to light.Problem 4When the temparature dif-ference of heat sink forpower transistor is remark-ably different.Problem 2Problem 3The pilot lamp lights onThe pilot lamp lights onfor 2 3 seconds afterfor a few minutes afterturning the power switchturning on the power switchon but the illumination lampwhile the illumination lampof the power switch goes outgoes out immediately.If the connector connectingHas the fuse blown?Check the idling current.power transistor to motherboard (P8200) is not off?YESNOYESNOReplace with a freshfuse.Does the voltage across theoutput terminals exceed-5V?Are the Q101 Q109transistors (PB-100)operating normally?Plug-in the connectorcorrectly.Are the power transistor(0201 0204) not inorder?NOYESNOYESNOYESReplace with a newrectifier bridge diode.NOIs the rectifier bridgediode normal?Replace defectivetransistor/s(0101 0109)if any.is the Q205 of DA-80 or0209 of DA-80M normallyoperating?Is the emitter resistornot in order?Replace the powertransistor.YESNOYESAre the 0101 0109transistors on PB-100operating normally?Replace transistor 0205 ofDA-80 or Q209 of DA-80M.Are the Q301 Q303transistors on PB-300operating normally?Replace the emitterresistor,NOYESNOYESReplace defectiveAre the Q201 Q204 ofReplace defectiveIf PR-201 of DA-80 ortransistor/sDA-80 or Q201 Q208transistor/sPR-301 of DA-80M was(0101 0109)of DA-80M power transis(Q301 0303)found defective, it mustif any.tors operating normally?if any.be replaced, NO IYES Replace defective powertransistors (0201 0204of DA-80 or 0201 0208of DA-80M) Defective circuit componentwas found in the powersupply circuit (transformer,electrolytic capacitor, orwiring) then replace it witha new component.Service InformationA method how to find out a defect in the circuit board PB100:Remove the circuit board PB100 from the mother board(PB 200) and turn on the current. Then, if the protectioncircuit does not operate, there is much possibility that thecircuit board is unusual. When the protection circuit operates,some trouble by short circuit of power transistor and unusualcircuit board PB 100 are supposed to be.When the circuit board PB100 is re-plugged in the motherboard (PB 200), it is advisable to perform after dischargingthe electric charge of power balancing electrolytic condenserwith some dummy resistors etc.7*00)P305VH 0C308 +VH otVQT oSK 303(0)K 303rSK 304els0100V0IN 0SW 0 OUT0SW INR302 C302Z 0e, 0 0P:0P306P3010301R303(:)*303K301Q302P3040VH 0400VL 0CR304C303 ,1 * 111*0306SK 301-10Oo oMcc cc cc(0)-SK3050VH 0K302C318 -I-T.1FG.313CR303C3I1N* .L C31277-T0314C3I6T P3020VL0+VL0Vs0+VHCR305C317-I I-0890/2300(Assy No. 6890/2300)R110._NL.zioiI R 104-VR 101flcr:I20u_.0101R1020110R103 .0101.4/or.*-40101 R/06Q1021Q103r I 1-.-0 1P301VLC3/5(0)-SK306VR102 Qiii.RI/8 1 0104108RII2_AA.A.,. 0107Q109RII3DA-80 P.C.B.0890/2100(Assy No. 6890/2100)0890/2200(Assy No. 6890/2200)8DA-80 P.C.B. PARTS LIST6890/2100P.C.B. Assy DriverRef. NO.Part NO.DescriptionPB-100/i020890210020P.C.B. DriverR-1010681225410Resistor 2.2M2 lAW CarbonR-1020673332229Resistor 3.3K52 /W Metal FilmR-103R1050683101216Resistor 100E2 YeiW Metal FilmR-1060683471215Resistor 470E2 Y4W Metal FilmR-1070683820210Resistor 82E2 /4W Metal FilmR-1080683151217Resistor 1500 Y4W Metal FilmR-1090683303218Resistor 30KE2 Y4W Metal FilmR-1100673511218Resistor 5102 IAW Metal FilmR-111, 1120683123210Resistor 12KE2 Y.M Metal Film8-113-1160683122216Resistor 1.2K2 4W Metal FilmR-117, 1180683104217Resistor 100K2 14W Metal FilmR-1190673103223Resistor 10KEZIAW Metal FilmR-121, 1220673519217Resistor 5.1E2 1/2W Metal FilmVR-101, 1022273202205Variable Resistor 21“2-BC-1010121031016Capacitor 0.01pF/630V M.F.C-1020142412010Capacitor 250PF StyrolC-1030143002019Capacitor 30PF StyrolC-104, 1050112271014Capacitor 220pF/6.3V Electrolytic0-1011868000109F ET 2N3922 or IT-5030-1021857000107pPA49AQ-103,11118530008302SC12790-10418510001202SA640 (F)Q106,10718530004472SC484 (Y)Q-108,10918510004442SC484 (Y)0-11018510001202SA640 (F)CR-101-10819300005041S1553Z-101195000060002Z12A6890/2200P.C.B. Assy MotherRef. NO.Part NO.DescriptionPB-200/i020890220028P.C.B. MotherPB-250/i02,iO40890225026P.C.B. SubR-201-2040655059310Resistor 0.47E2 2W CementQ-201,20218530007092SC1116AQ-203,20418510008002SA747A0-20518530005412SC496 (Y)6890/2300P.C.B. Assy Protection & S.P.S.Ref. NO.Part NO.DescriptionPB-300-1/i020890230010P.C.B. Protection & S.P.S.R-3010681103315Resistor 10KE2 14W CarbonR-3020681123311Resistor 121(2 4W CarbonR-303, 3040681333314Resistor 331(2 14W CarbonR-305, 3060681202319Resistor 2K0 Y4W CarbonR-3070681224312Resistor 2201“214W CarbonR-3080674301316Resistor mon Y2W Metal FilmR-3090681104319Resistor 100KE2 Y4W Carbon(for 100V input)0681274313Resistor 270KE2Y4W Carbon(for 200V input)CR-301, 30219300005041S1553303CR304, 3051930000703S2HB20C-303-3180121031016Capacitor 0.01gF/630V M.F.C-301, 3020112271014Capacitor 220pF/6.3V ElectrolyticSK301-3071700110001Spark Killer (0.1pF+1202)Q-301,30218630001071A170-30318610001041A02K-3010401024121NF-2-24V-DC (AE1324)K-302-1,303-1, 304-10402100229HC-2-AC100V (AP-3324)K-302-2,303-2, 304-20402200226HC-2-AC200V (AP-3325)90206 RII4 0105CRI08- VR102 -7004QI07.0 0CRIO4F.1TcRI:R105CR10314-Q109 1l-LI