Realistic-STA115-rec-sm 维修电路原理图.pdf

:EALrstCSerulceSTA-115SOLID STATEI J INT LAM IFM STEREO RECETVERCatalog Number : 31-2098CUSTOM MANUFACTUBED FOR RADIO SHACK, A DIVISION tF TANDY CORPORATIONRadioFans.CN 收音机爱 好者资料库PAGEELECTRICAL PERFORMIANCE SPECIFICATIONS ,. 3-7DISASSEMBLYINSTRUCTIONS. B-9BLOCKDIAGRAM. .10LEVEL DIAGRAM. ,.,.11DIALSTRINGING DIAGRAM. ,.,.,.11CTRCU|TDESCRIPTION :. .12-13OPERATIONAL CHECK FOR CIRCUITS 14 - 26ALIGNME NT I NSTRUCTIONS27 -32TROUBLESHOOTING. 33-35TUNER AUDIO P.C.B, (TOP & BOTTOM VIEWS) 36 - 37LEDP.C.B.(TOP&BOTTOMVIEWS). . .38SPEAKERSWTTCH P.C.B. (TOP&BOTTOM VIEWS). .39DIAL POINTER P.C,B. (TOP & BOTTOM VIEWS) . . . ,39WIRINGDIAGRAM .40EXPLODED VIEW 41 _- 42ELECTRICALPARTSLIST. .43-55EXPLODED VIEW PARTS LIST . 56 -_ 57TRANSISTOR LEAD IDENTIFICATION. .58IC LEAD IDENTIFICATION & INTERNAL DIAGRAM. 59 - 62SCHEMATIC DIAGRAM , .64- 65PRODUCT,SAFETY NOrteE , ,ManV.eiectric-al,and, rnech,anlcal par.ts,in ,this ihassii have specia|Ahaiaetefisties:,:,f,heCe,e harActef,.;r iiiiei,oitenlpiii1,unn,aiisld, ain6,.15e proiection,r61iqp6s6. by them cannot necessarily be obtained.brVr,Using.iepiacement, e:ompOnentsr, rated, toi:hi$her:,rvoltaggr,wattager,etc;, .Fle-pJater:nent,pails,thal:, ,conipronents,naving, sueS,isa,1u1s!,:6ie ioentitiea,bV er,A ,!n the sche.matic diagram.,ahd,the.nartiilist.,.Beteieali+Oiaiing.,a,n17.oftnese,ionrpoaenti.reid:16s parts list.in,this,ma-u;l,Careinjilfhitte ,.,sJnSiiiuta:repljcrrnen,ttpiiii.,ihai.Ao noi:traie,iflesarne,safety chaqacterlstics as specified in the.)RadioFans.CN 收音机爱 好者资料库ELECTRICAL PERFORMANCE SPECIFICATIONSWhole Specs are measured under the following conditions:1. The supply voltage is 120volts (U.S.A., Canada), (240voltsAC,50 Hzfor Australian models) froma regulated power supply.2. All measurements shall be taken under IHF measurement method unless otherwise specified.3. The power source must be insulated from other equipment, connected to antenna or output.4. The room temperature is 25C l77Fl.AM SectionNotes: 1. Output readings are taken across a non-reactive 47 k ohm load termination.2. Output is measured at TAPE OUT terminals.3. The generator output shall terminate in an IRE loop antenna.4. Standard modulation: 4OO H2,30% modulation.ITEMMeasuredat (kHz)UNITNOMINALLIMITFrequency coveragekHz510 - 1650520 - 1620I ntermediate FrequencykHz45520 dB Ouieting sensitivit.y60010001400pV lmpV lmpY lm250250250500500500Sensitivity at antenna terminal1 000pV20S/N Ratio at 5 mV/m input1 000dB4337Selectivity at S/N 20 dB input, r 10 kHz1 000dB2722Band width at 6 dB down1 000kHz64.5-9A.G.C. Figure of merit1 000dB5042I F rejection ratio600dB3227lmaqe Reiection ratio1400dB4538T.H.D. at 5mV/m input,30% mod.1 000o/o0.82.OOverload Distortion at 100mV/m input 80% mod.1 000o/o35Overload capacity at 80% mod.at 30% mod.1 0001 000mV/mmV/m200200100100Electrical audio f idelityRef .freq. = 1 kHz, -O dB down, 5mV/m input1 000Hz50-3k80 - 2.5kWhistle modulation (2nd) at SmV/mat 100mV/m(3rd) at 1mV/mat 5mV/mat 100mV/m910910o/oo,/o5.010.010.015.01 3651 365isoso/oo/oo/o5.010.010.010.015.0Frequency calibration6001 0001400kHzkHzkHz00 x25x40r50-3ITEMMeasuredat (kHz)UNITNOMINALLIMITSpurious response from 1650 - 30000 Hz1 000dB5044Tape out level, at 1 kHz SmV/m, RCA Jack*5mV/m, DIN Jack(3.3kC terminated)1 0001 000mVmV2003.3200 r2.5 dB3.3 t2.5 63The oscillator shall not drift more than 10 kHz starting at25C (77Fand thfough range up to50C (122F, at 1000 kHz.Meter Sensitivity at 1st LEDat 3rd LEDat sth LED10001 0001000mV/mmV/mmV/mo.41.05.0* For Australian models only.FM SectionNotes: 1. Output readings are taken across a non-reactive 47 k ohm load termination.2. Output is measured at TAPE OUT terminals.3. The signal voltage in this specification is the voltage appearing across the tuner input ter-minals (lHF).4. Standard modulation: 1000 H2,75 kHz deviation.Il-/ iIiiIi,ljliI(1TIti)1ll1tNIIl-/ tlitIIIILtlill1ililrjiIt.lIt1rlIIildt$l-/ tltl1ttt_lITEMMeasuredat (MHz)UNITNOMINALLIMITFrequency coverage (U.S.A., Canada, Australia)MHz87 .4 - 108.387.4 tO.5 -108 + 0.9 -0ntermediate frequencyMHz10.7HF (Useable) sensitivity90/98/1 0690/98/106pVdBf1.910.83.816.850 dB Ouieting sensitivity90/98/10690/98/106pVdBf3.5416.214.518.29Limiting sensitivity (-3 dB)98pV1.83.5S/N Ratio at 1mV input98dB7466S/Hum noise ratio at 1mV98dB7064Muting threShold98dB7.O4-10Frequency response t2.5 dB range, at 1mV input98Hz30 - 12k40 - 10kDistortion at quieting sens. at 100 Hzat 1000 Hzat 6000 Hz989898%o/oo/oo.4o.40.8Distortion at 1mV input at 100 Hzat 1000 Hzat 6000 Hz989898o/oo/loo/oo.250.0650.30.5Capture ratio98dB1.23.0Alternate channel selectivity at input 100pV98dB6045Spurious response ratio98dB7265lmage response ratio106dB6548lF response ratio90dB9070-4-IFM Stereo SectionNotes: l.Outputreadingsaretakenacrossanon-reactive4T kohmloadtermination.2. Output is measured at TAPE OUT terminals.3. Signal voltage in this specification is the voltage appearing across the tuner input terminalsflHF).4. Standard modulation: Main carrier (L+ R) -33.75 kHz (45%) dev.Sub carrier (L - R) - 33.75 kHz (45%) dev.Pitot (19 kHz) - 6.75 kHz (9%) dev.Modulation frequency - 1000 HzITEMMeasuredat (MHz)UNITNOMINALLIMITAM suppression at 1mV inPut9BdB6552AFC holding range at 100prV input98kHzx250t330Calibration accuracy90/98/1 06kHzt25OTape out level, 1 mV input at RCA, 75 k dev.*at Dl N, 22.5 k dev.9898mVmV6603.3660 t2.5 dB3.3 t2.5 dBMeter sensitivity at 1st LE Dat 3rd LEDat Sth LED9B989BpVpVpV4.525.O150Temperature range for satisfactory operationc0-45OF32 - 113Max. signal handling capacity9BpV200kAuto-M Range at 1mV inPut98MHztB00t600* * For Australian models only.ITEMMeasuredat (MHz)UNITNOMINALLIMITStereo beacon switching and muting threshold989BpVdBf722.135 - 1519.21 -28.75Stereo 50 dB quieting sensitivity90/98/106e0i98l1 06pVdBf39.837.2S/N Ratio at 1mV input (W/Low pass filter)9BdB7155Freq. response at 1mV input (50 - 10000 Hz)98dBt0t2.5Stereo distortion at 100 Hzat 1mV input at 1 kHz(WlLow pass filter) at 6 kHz98989B%o/oo/o0.80.20.81.5Stereo separation at 1mV at 100 Hzinput at 1 kHzat 10 kHz9B9B98dBdBdB384532283325Sub-carrier product rejection98dB3932SCA rejection98dB5045Tape out level at 1 kHz, RCA Jack1mV input98mV60060012.5 dB-5-Audio SectionNotes: All units are measured at SPEAKER terminals with non-reactive rated load (B ohms) unless -lotherwise indicated.Rated Power: 22W (RMS) Rated THD: 0.08%ITEMUNITNOMINALLIMITPower output from 20 Hz to 20 kHz under rated THD.Both channels driven 8Sl load (RMS).W2422lnput impedance at 1 kHz PHONOAUX/TVTAPE INke,koko505050Sensitivity for rated power PHONOAUX/TVTAPE INmVmVmV2.21601602.2 x2.5 dB160 r2.5 dB16012.5 dBTotal harmonic distortion from 20 Hzto at20 Hz2OkHz at rated power at 1 kHzat 20 kHzo/oo/oo/o0.030.0s0.030.080.080.08Max. input signal at rated THD (0.08%) PHONO(measured at Tape out) AUX/TVTAPEmVmVmV120lnfinitiveI nf initive90Frequency response from 20 Hz to 20 kHzdB0t2S/N Ratio PHONOA-weighted 1W reference (lHF) AUX/TVTAPEA-weighted rated power referencePHONO (1OmV input & shorted)AUX/TV (input shorted )TAPE (input shorted)dBdBdBdBdBdB72757585BB8B748080Dynamic headroomdB1.1Clipping headroomdB1.0Damping factor70Loudness contour ch. at 100 Hzat 10 kHzdBdB+6+ 4.5+ 6 12.5+4.5 !2.5Tone control responseBass control action at 100 HzTreble control action at 10 kHzdBdBt10t10t1O x2.5t 10 t2.5Filter cutoff freq. 30 Hz Cut Filter(-3 dB point) High FilterHzSee Filter curve on page 20.7KFilter slope 30 Hz Cut FilterHioh FilterdB/octdB/oct18.06.0Crosstalk at AUX/TV at 100 Hzat 1 kHzat 10 kHzdBdBdB706043454535A-weighted crosstalk at AUX/TV at 100 Hzat 1 kHzat 10 kHzdBdBdB856045-6-ITEMUNITNOMINALLIMITlM Distortion (SMPTE)o/o0.08o.2Transient overload recovery timepsec15Slew factor3.5Channel balance at V R maxdB0t 1.5DC Balance at no signal and outputmV0t50Tape out Level at RCA PHONO (input = 2.5mV)Jacks (47kQ terminated) AUX/TV (lnput = 160mV)mVmV140140140 13 dB140 t3 dBat DIN Jacks PHONO (lnput = 3.0mV)(3.3kOterminated) AUX/TV (lnput=Z2OmYlmVmV3.33.33.3 t2.5 dB3.3 t2.5 dBHum and noise at VR min.mV0.82.OPhono Eq. H IAA ch. from 2A Hz to 20 k Hz(measured at Tape out)dB10.5t2.O* Australian models only.-7 -DISASSEM BLY I NSTRUCTIONS1) To remove the cabinet(A) Remove two screws from each side of cabinet (Figure A).Be careful not to lose the screw inserts when the screws are removed.Figure ARemove three screws from upper back panel (Figure B).(B)lt:i t:t:L:l l,t:t:t 1 i ! :t:t:i;!l;i i :. _ :.:a :. 4:;t:l:ttt:i:.ffiFigure B2) To remove the bottom cover(A) Turn the receiver upside down and remove twelve screws from the bottom (Figure C).(B) Lift the bottom cover off .i,.,.Nir.Nil,.ia.1.,l,il$Ni;rls$.4r.3) To remove the front panel (aluminum panel)(A) Remove the cabinet and bottom cover as described in 1. and 2.(B) Remove three screltrs from top of front panel (Figure D).Figure D(C) Remove three screws from bottom of front panel (Figure E).(D) Remove seven knobs from the frontselector (c), tuning (d) and volume (e)Figure Epanel which is: Power (a), bass, treble, balance (b),(Figure F).-_Y_-_J(b)Figure F9-:ariee4g$Ae- .$ta-lr* tlrrrM:qtqae:e*rvrnG_P;6JLlJzz-oFLrlrJJooo,EoaJtdzz-oFI(,(ts2HF-o=R=EutsEuEo!Iu -:9cVo,ou=oz)o -5=9i-za)i oFEUUSf.3trXo=x=9L-)Eig6;uo ndE3HzeF3,3E3c=Ze9os8! oFH=5FiNU J=o =o:Eluu!e=lJEro=lLOJEzo )0Fo6*su=otaoixZY=oooEUZJ*o- uI-drrOU;6b;=GP_a*osx=6-3tIooJFz-z a.f o1 ts -= orrE-EE=FIoE9EtrIF5?Eg2EoLJzzoolaLEo0EUILF5Iauo 5BLOCK DIAGRAMIIIIIILII_li*LdrHMia I I - I- -l-1ig + + : + + +ig -s* *ExI tgJi ooJ I Go; I I a Ii _J | =ao I I II iE Lx;- L=-.1I Fo Fr =l6ouzFOl-=l:=Za=fLL-zoJ6o=zs)cFzoJ6a*z9rLObF=iaFzEEPOWER TRANSFORMEREo_tsJNlouEg9okoJFfo0-U&e9oJNlo0-UE10rTAPE INIIFlL AUX,/ TVzTLpHottoWhen stringing dial1. Start with capacitor set at maximum.(plates fully closed)2. Pointer position should be at low end.3. Start at tension spring.4. Finish at eyelet.LEVEL DIAGRAMSPEAKERO UTPU T22w / AOc)3)UJUJ)70605028.4 dBto.odB3020too37.2 dBDIAL STRINGING DIAGRAMPHONOEQ AMPSWITCHTONECONTROLMAINAMPAUDIO FREQUENCY ( lkHz )- 11 *Ytr-u-CIRCUIT DESCRIPTIONPROTECTION CIRCUITSThe output from tone amp circuit to main amp circuit isswitched on/off with two FETsTR601 andTR602. When pin 10 of 1C601 is high, the FETs are on; when low, FETs are off.The switching will take place in the following three instances.1 . Tu rn ing the receiver on and off ( F igure 1 )When the power is switched on, both pins 1 and 2 of 1C601 are high, so pin 3 also becomes high andhence pin 4 goes high. After the delay time set by the time constant R607 and C608, pin 10 of1C601 becomes high and signals from the tone amp are fed to main amp. This time constant R607and C608 is required to keep the speakers off to protect them from the switching transients.At power off, DC voltage will not turn off immediately, so the AC portion is taken from the secon-dary of the power transformer via D606 to pin 1 and 2. When this goes low, pin 3 goes low, C608 isdischarged by D602, and pin 10 goes low.loTONE AMP(L)loMAIN AMP( L)A!IIlo B+to B-D6O6 D6O2Figure 12. Changing the selector switch position (Figure 2)This prevents the switching noise from going to the speakers. The selector switch is a shorting type;when it is turned from one position to another, the switch contact will make a momentary shortcircuit to ground. This low level is applied to pin 12 of 1C601. Pin 11 goes low, pin 10 goes lowthrough the time constant circuit C607, D603 and R608. The time constant is required so thecut- off condition lasts for about 0.3 to 0.6 seconds.,oMAIN AMP(R)-12-3. Speaker terminal is shorted/low impedance speakers are used (Figure 3)lf either of the above takes place, an excessively high current flows from emitter to collector ofTR511/TR512, and a voltage appears across R533/R534. This voltage is applied to gate of theSCR601 via D505/D506. When this voltage exceeds 0.7V, SCR conductsand pin 13of 1C601 goeslow, C607 is discharged by D603, and pin 10 goes low. toTONE AMP(R)Abnormal Temperature Rise Protection (Figure 4)The STA-1 15 has two thermal protectorslf the temperature of the main amp heat sink rises to 1O5C1221 F (or power transformertemperaturerises to 95C/20,3F) the thermal protector switch makes an open circuit and the power supply will becut off. This protects the main amp and power transformer. ln this case, the amplifier automaticallyshuts down and output will dropto 0V. lf this should occur,turn the receiveroff. When thetemper-ature of the main amp heat sink falls to within the operating limits of the receiver, the thermal protec-tor switch will reset itself. When the problem is corrected, turn the receiver on again.ACl2OV 6OHzFigure 4-13-YzE6r9tsEEIU;iIEqE2t9E=HrGtscuoEE-;,tluloo ;Eol6lil- Is# Iatlftq Ia-i Ior Io I_lIzaI,zFd)Ii 38I EFstl*Et-iiI:rt Rch /o RchloRchFigure 3OFUUIJ9FEl=o2eOPERATIONAL CHECK FOR CIRCUITSPower Supply Operation Check. aonn.t AC cord to standard AC power rorr.l(o Power switch ON and dial lamp should light. )(1) Check power supply circuit onTUNER AUDIO P.C.B., fuses,and power transformer.(2) See TROUBLESHOOTING onPage 33.DC voltages are not correct.DC voltages are correct.STARTCONNECTIONREPAIR-B+ +!ro TONE CONTROL& PROTECTORIB-L_Proceed to next sectionAudioSection Operation Check(. Conn.t BO load to speaker output.| . Connu.t DC voltmeters to C701 (minus -( to ground) of main amp circuits on TUNERi-i_c_e9(qo_ryeMp_p.!y_yot_ao_e_vyiLh_1qIPyt_r*Must be t30.5V IO.SV.*(1) Check D701, C701, C702.(2) Check for short-circuits.(3) See T RO UB LESHOOTI NG on page 33.DC voltage is not t31V t0.5VDC voltage is t31V t0.5VFigure 5702 (PC.B.c702DC VOLTMETER DC VOLTMETERFigure 6)andCC.B.ER AUDIOndP.TUI70tUNE)lolm t*fCONNECTIONSTEP 1:CKREPAIRCHtLJOK1to grAUD-14-iAdjust DC balance and idling current. rl_s9e_4!r_GryV_ENILsIEqqr_r9rys_gLqage_?B_._i. Conn., DC voltmeter to pin 11 (L) or pin 12 (R)l( and GROUND of TUNER AUDIO P. C. B. )DC VOLIMETERFigure 7i_.1.:f !iplqry:_t_r_._*lrgs: g, L_.1J n .r,rr,.ir.pr. ,_li1a .* within t50mV.*(1)CheckTR501 (L) orTR502 (R).DC voltage over t50mVDC voltage within t50mV(:. Conn.t DC voltmeter to R531 (L ch) or R532 (R ch)JFigure 8icrrect the idling urlniot *rr lrnp *i.1 ip;.- -tCheck the DC voltage across emitter resistor R529 (R531) (L ch) andlnsso (Rb32) (R ch).*should be 2.35mV +4.71-1.88mV. *(1) Check the value of R519 (L ch) and R520 (R ch).IFor Australian models, adjust VR 501(L ch) and VR 502 (R ch).(2) Check the bias circuit of D501, D503 (L ch) and/or D502, D504 (R ch).(3) Check TR503 (L ch) and TR504 (R ch).(4) Check TR501, (L ch) and TR502 (R ch).(5) Check for short-circuits on TUNER AUDIO P.C.B.DC voltage is above 7.05mV or below 0.47mV.DC voltage is 2.35mV +4.71-1.BBmV.iIIIIIIADJUSTMENTREPAIR- 15 -CONNECTIONREPAIRADJUSTMENTR EPAIRCHECK(.l.l.tConnect oscilloscope and V.T.V.M. to speaker terminal. lConnect 8O load to speaker output. Connect audio osc. to input of main amp circuit: C501s plus (+) side (L),1and/or C502s plus (+) side (R) |lnput should be 500mV and output should be 13.3V (at 1 kHz) )OSCILLOSCOPE VIV.MauDro osc. TUNER,AUDTO PC.3en LoA