Stax-DA80-pwr-sm维修电路原理图.pdf

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1、This manual is a guide to adjustment methods, diagrams and parts list for DA-80 and DA-80M. OUTLINE OF CIRCUITRY 2 HANDLING INSTRUCTION 3 INTERNAL VIEW 4 ADJUSTMENT 5 POWER LAMP REPLACEMENT6 TROUBLESHOOTING GUIDE 7 DA-80 P.C.B. 8 DA-80 P.C.B. PARTS LIST 9 DA-80M P.C.B. 10 DA-80M P.C.B. PARTS LIST 11

2、 DA-80/DA-80M PARTS LIST 12 DA-80 SCHEMATIC DIAGRAM . . . 13 DA-80M SCHEMATIC DIAGRAM . . 15 SPECIFICATIONS 17 RadioFans.CN 收音机爱 好者资料库 (9 (2 5107 0201 0202 Q203 0204 110 010 Attenuafor (l ( Differential (3, Amp 08102 Bias (4) Constant Current Circuit Input Jack 0 Short Circuit P t t Overheat Protect

3、or DC Pr rector (8) NFB Circuit Output Tarminal 0205 0206 0207 0208 0109 PNP Darlington Power Amp SUMMARY OF CIRCUITRY The input is fed, via an attenuator, to the gate of the first stage dual FET differential amplifier (3). The diode connected between the two gates is the protective circuit for inpu

4、t overloads (1). The NFB signal (8) is applied to the gate shown. The dual FET differential amplifier functions under ideal condi- tions due to the connection of the constant current supply (4) to the common source. The current is reversed in the current mirror circuit (2), driving Q110 in the casca

5、de amplifier (5) and 0108, which DA-80 form the push-pull configuration, at constant current. A pair of transistors with common bases and symmetrical emitters are enclosed to the same can in the current mirror circuit. This en- sures that the current flowing in each transistor is the same, independe

6、nt of the ambient temperature. Q110 and Q108 are cascade connected, consisting of transistors with extremely good high frequency characteristics and equiva- lent characteristics. The bias circuit (6) gives the optimum bias as set by VR102, passes through the short-circuit protector (7), then through

7、 Q107, 0109, the drive-stage transistors for the Darlington power amplifier (9) (10), then to the power transistors Q201-Q204, and Q205 0208, of the Darlington-connected power output stage. The configuration adopted for the Darlington power am- plifier has NPN (9) and PNP (10) tran- sistors in a ful

8、ly complementary single- ended push-pull class A output stage. The circuitry has ample stability for class A DC amplifier operation, with all possible circuit elements that could cause degradation of sound quality eliminated. AID Current Mirror (2) Attenuator Overload Protector Input Jack Differenti

9、al Amp 0 NPN Darlington Power Amp (51(9 0107 0110 0201 0202 .0 fibs V 0108 Short Circuit Ef Protector Output Tarminal (7) 0 VRI020) Bias 0203 0209 Cir 0109 0 0 PNPDarlington Pow r Amp v_ Constant Current Circuit (8I Overheatt Protector Transformer DC Protector ,-0 0 G DC Power Supply +Vn ,308) Vcf1(

10、 30V) DC Power Supply C +V+40V)( Vr ( 40V) L/R INDEPENDENT POWER SUPPLY INDICATION SIGNAL CIRCUIT SINGLE CHANNEL DC Power Supply DC Power Supple +Vcc1(+30V) .- n( 30V) 4V,f(*4001 V ( 40V) DA-80M Current MirroCascade AmpNPN Darlington PowerPower Amp Voltage SelectorPo e rTransfor me o C +V (+37V) VI,

11、 37V) +VGAL-37V) Vf( 37V) DC Power Supply -. 0ec DC Power Supply 2 RadioFans.CN 收音机爱 好者资料库 240Vr r 117V IDLING INSTRUCTION (1)Location in use This amplifier features class-A opera- tion, and special care should be taken with respect to heat radiation. Avoid locations exposed to direct sunlight, and

12、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 should avoid places where dust is liable to be attracted. (2)Protective circuits Four different kinds of protective cir- cuit are used to protect either

13、the am- plifier or the speakers from damage or loss. 1.Overload (input) protection: The input needed for maximum output is 0.89 V. Should this reach 50 V, a clip circuit operates to prevent the amp. from being driven to full output. 2.PC limiter: This circuit limits the current which flows through t

14、he output transistors to prevent them from being destroyed by the ex- tremely large current which would otherwise flow if the speaker terminals were short-circuited. 3.Temperature protection: This cir- cult was designed to cut off the electrical power supply to the amplifier as soon as exceptionally

15、 high temperatures are reached. It prevents the amp. from being damaged by rises in the ambient temperature. 4.Speaker protection: The speakers will be protected from direct current signals greater than 5 V appearing at the amplifier output terminals in the face of direct current signals from the pr

16、eam- plifier or from switching tran- sient noise. Protection is by cutting off the amp. electrical power sup- ply, and is effective even if the amp. itself is damaged. The above protective circuits built into the amplifier provide protec- tion against the most unlikely eventualities, but you should

17、take care to use the amp. so that the protective circuits are not caused to operate. If, for the causes detailed in 3 and 4, the protective circuits cut off the electrical power supply, switch the amplifier off, determine the cause, and remove it before switch- ing the electrical power on again. If

18、the protective circuit functions in the same way again, cutting off the power a second time, please read the TROUBLESHOOTING GUIDE on the 7 page. (3)When using condenser-type speak- ers Since condenser-type (or electrostatic) speakers only have a DC impedance of the order of one ohm, near-DC signals

19、 arising from eccentric or warped re- cords, or from external vibration, will cause the short-circuit protection to operate, which will be heard as a click- ing or popping noise. If this situation should arise, you should insert a one or two-ohm resistor (rated 30 Watts) between the speaker and the

20、amplifier output terminal as shown, and set the AC/DC switch to AC. (4)When using the DA-80/80M as the mid- or high-frequency amplifier in a multi-amplifier configuration When the DA-80/80M is used for the mid/high frequency amplifier, the channel divider cuts out the low fre- quency component of th

21、e signal, so that there is no possibility of DC or other very low frequency signal of very high amplitude being applied to the speakers. The possibility does remain, however, of the speakers being dam- aged by the switching noise from the channel divider or by mistakenly pull- ing out an input jack

22、plug. The AC/DC switch 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)Measurements This amplifier boasts extremely high quality circuitry, and if meaningful measurements are to be taken of its exceptionall

23、y good performance, only correspondingly high quality measur- ing instruments and sophisticated measuring techniques should be used. (6)Others DA-80 *The AC Outlets are not linked to the amplifier power switch. *There are two models of the DA-80, one intended for 100117V operation and the other for

24、200230 V opera- tion. In both models the switch for selection of the actual operating volt- age to be used is to be found on the underside of the amplifier. 100V-108V aria 109V-117V aria To comply with the voltage where this equipment is used, this plate has to be removed and re-set after switched t

25、o the required voltage. A 2 i oV 2 0 V aria DA-80M A choice of mains supply voltages for the DA-80M is given by the voltage selector under the chassis. This offers a choice of 100V, 117V, 220V, and 240V. If you need to change the oper- ating voltage, first remove the protec- tive metal device, and t

26、hen set the arrow so that it points to the voltage closest to that which you will use. O 200V-2 I uV aria 3 UU 0 0 0 0 ui 00 00o 0 o P.C.B.(0890/4300) Power transformer Off-set voltage adjustment (VR101) PB-100/iO4 (Assy No.6890/4100 1) Idle current adjustment (VR102) u U u ail 121 121 71 INTERNAL V

27、IEW DA-80 =LILJ 0 NVAtgl ic, 00 IIN I 1 IIIN II 0 : Itttx 0 rr.-rn77 U Off-set voltage adjustment (VR101) PB-100/i02 (Assy No.6890/2100 1) Idle current adjustment (VR102) P.C.B.(0890/2300) Power transformer El PB-200/i02 (Assy No.6890/2200) DA-80M PB-200/iO4 (Assy No.6890/4200) 4 no Idle Current Adj

28、ustment Idle current adjustment (VR102) 11 Volt meter Off-set Voltage Adjustment Volt meter off-set adjustment (VR101) ADJUSTMENT DA-80 *Idle Current Adjustment 1.Switch the voltmeter range over to DC 0.5V. 2.Switch the power on and exem- plifyingly measure the voltage of R201 at the both ends. Then

29、 adjust VR102 to make this voltage 400mV40mV. 3.30 minutes later, measure the voltage of R201 at the both ends and readjust VR102 to make this voltage 350mV35mV. *Off-set Voltage Adjustment (To be performed after completing the idle current adjustment) 1.Leave the voltmeter range at 0.5V. 2.Connect

30、the voltmeter to the out- put terminals, and adjust VR101 to reduce the voltage to OV. Then switch the voltmeter over to the 0.25V range, and fine adjust until a OV reading is obtained. 3.Measure again 30 minutes later, fine adjusting to OV if necessary. The above procedure refers to the adjustment

31、of the one channel only. The other channel is also adjusted by the same procedure. DA-80M *Idle Current Adjustment 1.Switch the voltmeter range over to 0.5V. 2.Switch the power on and exem- plifyingly measure the voltage of R201 at the both ends. Then adjust VR102 to make this voltage 250mV25mV. 3.3

32、0 minutes later, measure the voltage of R201 at the both ends and readjust VR102 to make this voltage 230mV23mV. *Off-set Voltage Adjustment (To be performed after completing the idle current adjustment) 1.Leave the voltmeter range at 0.5V. 2.Connect the voltmeter to the out- put terminals, and adju

33、st VR101 to reduce the voltage to OV. Then switch the voltmeter over to the 0.25V range, and fine adjust until a OV reading is obtained. 3.Measure again 30 minutes later, fine adjusting to OV if necessary. 5 This will be better to cover with rubber tube. POWER LAMP REPLACEMENT 1. Hold concave part o

34、f the white plastic cover firmly with nails leaving the power switch off and pull inside to detach the cover. 2. Hold the lamp lightly with a plier or any else and pull inside to remove. 3.Push-into a fresh lamp with fingers. 4.Place the cover back as was before. 6 TROUBLESHOOTING GUIDE Problem 1 So

35、on after the power switch is turned on, illumination lamp and the pilot lamp fail to light. Problem 4 When the temparature dif- ference of heat sink for power transistor is remark- ably different. Problem 2 Problem 3 The pilot lamp lights on The pilot lamp lights on for 2 3 seconds after for a few m

36、inutes after turning the power switch turning on the power switch on but the illumination lamp while the illumination lamp of the power switch goes out goes out immediately. If the connector connecting Has the fuse blown? Check the idling current. power transistor to mother board (P8200) is not off?

37、 YES NO YES NO Replace with a fresh fuse. Does the voltage across the output terminals exceed -5V? Are the Q101 Q109 transistors (PB-100) operating normally? Plug-in the connector correctly. Are the power transistor (0201 0204) not in order? NO YES NO YES NO YES Replace with a new rectifier bridge d

38、iode. NO Is the rectifier bridge diode normal? Replace defective transistor/s (0101 0109) if any. is the Q205 of DA-80 or 0209 of DA-80M normally operating? Is the emitter resistor not in order? Replace the power transistor. YES NO YES Are the 0101 0109 transistors on PB-100 operating normally? Repl

39、ace transistor 0205 of DA-80 or Q209 of DA-80M. Are the Q301 Q303 transistors on PB-300 operating normally? Replace the emitter resistor, NO YES NO YES Replace defective Are the Q201 Q204 of Replace defective If PR-201 of DA-80 or transistor/s DA-80 or Q201 Q208 transistor/s PR-301 of DA-80M was (01

40、01 0109) of DA-80M power transis (Q301 0303) found defective, it must if any. tors operating normally? if any. be replaced, NO IYES Replace defective power transistors (0201 0204 of DA-80 or 0201 0208 of DA-80M) Defective circuit component was found in the power supply circuit (transformer, electrol

41、ytic capacitor, or wiring) then replace it with a new component. Service Information A method how to find out a defect in the circuit board PB 100: Remove the circuit board PB100 from the mother board (PB 200) and turn on the current. Then, if the protection circuit does not operate, there is much p

42、ossibility that the circuit board is unusual. When the protection circuit operates, some trouble by short circuit of power transistor and unusual circuit board PB 100 are supposed to be. When the circuit board PB100 is re-plugged in the mother board (PB 200), it is advisable to perform after dischar

43、ging the electric charge of power balancing electrolytic condenser with some dummy resistors etc. 7 *00) P305 VH 0 C308 +VH o tVQ T o SK 303 (0) K 303 r SK 304 els 0 100V0 IN 0 SW 0 OUT0 SW IN R302 C302 Z 0 e, 0 0 P:0 P306 P3010301R303 (:)*303 K301 Q302 P304 0 VH 0 400 VL 0 CR304 C303 ,1 * 111 * 030

44、6 SK 301 -10 Oo o M cc cc cc (0)- SK305 0 VH 0 K302 C318 -I- T .1FG.313 CR303 C3I1 N * .L C312 77- T 0314 C3I6 T P302 0VL 0+VL 0Vs 0+VH CR305 C317 -I I- 0890/2300 (Assy No. 6890/2300) R110 ._NL.zioi I R 104 - VR 101 flcr:I20 u_. 0101 R102 0110 R103 .0101.4/or. *-4 0101 R/06 Q102 1 Q103 r I 1-.-0 1 P

45、301 VL C3/5 (0)- SK306 VR102 Qiii. RI/8 1 0104 108 RII2 _AA.A.,. 0107 Q109 RII3 DA-80 P.C.B. 0890/2100 (Assy No. 6890/2100) 0890/2200 (Assy No. 6890/2200) 8 DA-80 P.C.B. PARTS LIST 6890/2100 P.C.B. Assy Driver Ref. NO.Part NO.Description PB-100/i020890210020P.C.B. Driver R-1010681225410Resistor 2.2M

46、2 lAW Carbon R-1020673332229Resistor 3.3K52 /W Metal Film R-103R1050683101216Resistor 100E2 YeiW Metal Film R-1060683471215Resistor 470E2 Y4W Metal Film R-1070683820210Resistor 82E2 /4W Metal Film R-1080683151217Resistor 1500 Y4W Metal Film R-1090683303218Resistor 30KE2 Y4W Metal Film R-110067351121

47、8Resistor 5102 IAW Metal Film R-111, 1120683123210Resistor 12KE2 Y.M Metal Film 8-113-1160683122216Resistor 1.2K2 4W Metal Film R-117, 1180683104217Resistor 100K2 14W Metal Film R-1190673103223Resistor 10KEZIAW Metal Film R-121, 1220673519217Resistor 5.1E2 1/2W Metal Film VR-101, 1022273202205Variab

48、le Resistor 21“2-B C-1010121031016Capacitor 0.01pF/630V M.F. C-1020142412010Capacitor 250PF Styrol C-1030143002019Capacitor 30PF Styrol C-104, 1050112271014Capacitor 220pF/6.3V Electrolytic 0-1011868000109F ET 2N3922 or IT-503 0-1021857000107pPA49A Q-103,11118530008302SC1279 0-10418510001202SA640 (F

49、) Q106,10718530004472SC484 (Y) Q-108,10918510004442SC484 (Y) 0-11018510001202SA640 (F) CR-101-10819300005041S1553 Z-101195000060002Z12A 6890/2200 P.C.B. Assy Mother Ref. NO.Part NO.Description PB-200/i020890220028P.C.B. Mother PB-250/i02,iO40890225026P.C.B. Sub R-201-2040655059310Resistor 0.47E2 2W Cement Q-201,20218530007092SC1116A Q-203,20418510008002SA747A 0-20518530005412SC496 (Y) 6890/2300 P.C.B. Assy Protection 0109QI