Realistic-STA115-rec-sm 电路图 维修手册.pdf

:EALrstC Serulce STA-115 SOLID STATEI J INT L AM IFM STEREO RECETVER Catalog Number : 31-2098 CUSTOM MANUFACTUBED FOR RADIO SHACK, A DIVISION tF TANDY CORPORATION RadioFans.CN 收音机爱 好者资料库 PAGE ELECTRICAL PERFORMIANCE SPECIFICATIONS ,. 3-7 DISASSEMBLYINSTRUCTIONS. B-9 BLOCKDIAGRAM. .10 LEVEL DIAGRAM. ,.,.11 DIALSTRINGING DIAGRAM. ,.,.,.11 CTRCU|TDESCRIPTION :. .12-13 OPERATIONAL CHECK FOR CIRCUITS 14 - 26 ALIGNME NT I NSTRUCTIONS27 -32 TROUBLESHOOTING. 33-35 TUNER AUDIO P.C.B, (TOP 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.nartii list. ,.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 SPECIFICATIONS Whole Specs are measured under the following conditions: 1. The supply voltage is 120volts (U.S.A., Canada), (240voltsAC,50 Hzfor Australian models) from a 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 Section Notes: 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. ITEM Measured at (kHz) UNITNOMINALLIMIT Frequency coveragekHz510 - 1650520 - 1620 I ntermediate FrequencykHz455 20 dB Ouieting sensitivit.y600 1000 1400 pV lm pV lm pY lm 250 250 250 500 500 500 Sensitivity at antenna terminal 1 000pV20 S/N Ratio at 5 mV/m input1 000dB4337 Selectivity at S/N 20 dB input, r 10 kHz1 000dB2722 Band width at 6 dB down1 000kHz64.5-9 A.G.C. Figure of merit1 000dB5042 I F rejection ratio600dB32 27 lmaqe Reiection ratio1400dB4538 T.H.D. at 5mV/m input,30% mod.1 000 o/ /o0.82.O Overload Distortion at 100mV/m input 80% mod.1 000 o/ /o35 Overload capacity at 80% mod. at 30% mod. 1 000 1 000 mV/m mV/m 200 200 100 100 Electrical audio f idelity Ref .freq. = 1 kHz, -O dB down, 5mV/m input 1 000Hz50-3k80 - 2.5k Whistle modulation (2nd) at SmV/m at 100mV/m (3rd) at 1mV/m at 5mV/m at 100mV/m 910 910 o/ /o o,/ /o 5.0 10.0 10.0 15.0 1 365 1 365 isos o/ /o o/ /o o/ /o 5.0 10.0 10.0 10.0 15.0 Frequency calibration600 1 000 1400 kHz kHz kHz 0 0 x25 x40 r50 -3 RadioFans.CN 收音机爱 好者资料库 ITEM Measured at (kHz) UNITNOMINALLIMIT Spurious response from 1650 - 30000 Hz1 000dB5044 Tape out level, at 1 kHz SmV/m, RCA Jack *5mV/m, DIN Jack (3.3kC terminated) 1 000 1 000 mV mV 200 3.3 200 r2.5 dB 3.3 t2.5 63 The oscillator shall not drift more than 10 kHz starting at25C (77Fand thfough range up to 50C (122F, at 1000 kHz. Meter Sensitivity at 1st LED at 3rd LED at sth LED 1000 1 000 1000 mV/m mV/m mV/m o.4 1.0 5.0 * For Australian models only. FM Section Notes: 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. I l -/ i I i i I i,l jl i I ( 1 T I t i ) 1 ll 1t N I I l -/ t l i t I I I IL tl il l1 il il rj i I t.l I t1 rl I I il dt $l -/ tl tl 1 t t t _l ITEM Measured at (MHz) UNITNOMINALLIMIT Frequency coverage (U.S.A., Canada, Australia)MHz87 .4 - 108.387.4 tO.5 - 108 + 0.9 -0 ntermediate frequencyMHz10.7 HF (Useable) sensitivity90/98/1 06 90/98/106 pV dBf 1.9 10.8 3.8 16.8 50 dB Ouieting sensitivity90/98/106 90/98/106 pV dBf 3.54 16.21 4.5 18.29 Limiting sensitivity (-3 dB)98pV1.83.5 S/N Ratio at 1mV input98dB7466 S/Hum noise ratio at 1mV98dB7064 Muting threShold98dB7.O4-10 Frequency response t2.5 dB range, at 1mV input98Hz30 - 12k40 - 10k Distortion at quieting sens. at 100 Hz at 1000 Hz at 6000 Hz 98 98 98 % o/ /o o/ /o o.4 o.4 0.8 Distortion at 1mV input at 100 Hz at 1000 Hz at 6000 Hz 98 98 98 o/ /o o/ lo o/ /o o.25 0.065 0.3 0.5 Capture ratio98dB1.23.0 Alternate channel selectivity at input 100pV98dB6045 Spurious response ratio98dB7265 lmage response ratio106dB6548 lF response ratio90dB9070 -4- I FM Stereo Section Notes: 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 terminals flHF). 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 Hz ITEM Measured at (MHz) UNITNOMINALLIMIT AM suppression at 1mV inPut 9BdB65 52 AFC holding range at 100prV input98kHzx250t330 Calibration accuracy90/98/1 06kHzt25O Tape out level, 1 mV input at RCA, 75 k dev. *at Dl N, 22.5 k dev. 98 98 mV mV 660 3.3 660 t2.5 dB 3.3 t2.5 dB Meter sensitivity at 1st LE D at 3rd LED at Sth LED 9B 98 9B pV pV pV 4.5 25.O 150 Temperature range for satisfactory operation c0-45 OF 32 - 113 Max. signal handling capacity 9B pV 200k Auto-M Range at 1mV inPut98MHztB00t600 * * For Australian models only. ITEM Measured at (MHz) UNITNOMINALLIMIT Stereo beacon switching and muting threshold 98 9B pV dBf 7 22.13 5 - 15 19.21 -28.75 Stereo 50 dB quieting sensitivity90/98/106 e0i98l1 06 pV dBf 39.8 37.2 S/N Ratio at 1mV input (W/Low pass filter)9BdB 7155 Freq. response at 1mV input (50 - 10000 Hz) 98dBt0t2.5 Stereo distortion at 100 Hz at 1mV input at 1 kHz (WlLow pass filter) at 6 kHz 98 98 9B % o/ /o o/ /o 0.8 0.2 0.8 1.5 Stereo separation at 1mV at 100 Hz input at 1 kHz at 10 kHz 9B 9B 98 dB dB dB 38 45 32 28 33 25 Sub-carrier product rejection98dB 3932 SCA rejection98 dB5045 Tape out level at 1 kHz, RCA Jack 1mV input 98mV60060012.5 dB -5- Audio Section Notes: All units are measured at SPEAKER terminals with non-reactive rated load (B ohms) unless -l otherwise indicated. Rated Power: 22W (RMS) Rated THD: 0.08% ITEMUNITNOMINALLIMIT Power output from 20 Hz to 20 kHz under rated THD. Both channels driven 8Sl load (RMS). W2422 lnput impedance at 1 kHz PHONO AUX/TV TAPE IN ke, ko ko 50 50 50 Sensitivity for rated power PHONO AUX/TV TAPE IN mV mV mV 2.2 160 160 2.2 x2.5 dB 160 r2.5 dB 16012.5 dB Total harmonic distortion from 20 Hzto at20 Hz 2OkHz at rated power at 1 kHz at 20 kHz o/ /o o/ /o o/ /o 0.03 0.0s 0.03 0.08 0.08 0.08 Max. input signal at rated THD (0.08%) PHONO (measured at Tape out) AUX/TV TAPE mV mV mV 120 lnfinitive I nf initive 90 Frequency response from 20 Hz to 20 kHzdB0t2 S/N Ratio PHONO A-weighted 1W reference (lHF) AUX/TV TAPE A-weighted rated power reference PHONO (1OmV input !l;i i :. _ :.:a :. 4: :;t:l:ttt:i:.ffi Figure B 2) 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 $Ni;rl s$.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 front selector (c), tuning (d) and volume (e) Figure E panel which is: Power (a), bass, treble, balance (b), (Figure F). -_Y_-_J (b) Figure F 9- :ariee4g$Ae- .$ta-lr* tlrrrM:qtqae:e*rvrn G_ P; 6 J LlJ z z - o F Lr lrJ J o o o, E o a J td z z - o F I (, (ts 2H F- -o =R =Euts E u Eo! Iu - :9cVo ,ou=o z)o - 5=9i- za<) i o F E UU Sf. 3trXo =x =9L- )Ei g6; uo n dE3 Hze F3, 3E3 c = Ze 9o s8 ! oF H=5 FiN U J= o = o : E luu !e =l J< E ro =lLO J <E zo ) 0Fo 6*s u=o tao ix ZY =< oo oE UZ J* o - uI -drr OU; 6b; = G P_ a*o sx= 6-3 tIo o< JF z -z a .f o 1 ts -= o r r E- EE =F Io E9 Etr IF 5? Eg 2E o L J zz oo la L Eo 0 E UIL F 5Ia uo 5 BLOCK DIAGRAM I I I I I I L I I _l i*LdrHM ia I I - I- -l-1 ig + + : + + + ig -s* *ExI tgJ i ooJ I Go; I I a I i _J | =ao I I I I iE Lx;- L=-.1 I Fo Fr = l6o uz FO l- =l:= Za =fLL - z o J 6 o = z s ) c F z o J 6 a * z 9r LO bF =ia F z E E POWER TRANSFORMER E o_ ts JN lo u E g 9o ko JF fo 0- U 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 and hence pin 4 goes high. After the delay time set by the time constant R607 and C608, pin 10 of 1C601 becomes high and signals from the tone amp are fed to main amp. This time constant R607 and 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 is discharged by D602, and pin 10 goes low. lo TONE AMP (L) lo MAIN AMP ( L) A ! I I lo B+ to B- D6O6 D6O2 Figure 1 2. 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 short circuit to ground. This low level is applied to pin 12 of 1C601. Pin 11 goes low, pin 10 goes low through the time constant circuit C607, D603 and R608. The time constant is required so the cut- off condition lasts for about 0.3 to 0.6 seconds. ,o MAIN 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 of TR511/TR512, and a voltage appears across R533/R534. This voltage is applied to gate of the SCR601 via D505/D506. When this voltage exceeds 0.7V, SCR conductsand pin 13of 1C601 goes low, C607 is discharged by D603, and pin 10 goes low. to TONE AMP (R) Abnormal Temperature Rise Protection (Figure 4) The STA-1 15 has two thermal protectors lf the temperature of the main amp heat sink rises to 1O5C1221 F (or power transformertemperature rises to 95C/20,3F) the thermal protector switch makes an open circuit and the power supply will be cut off. This protects the main amp and power transformer. ln this case, the amplifier automatically shuts 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. AC l2OV 6OHz Figure 4 -13- Y zE 6r9 tsEE IU; iIE qE 2t9 E=H rGts cuo EE -;,t lul oo ; Eol 6l il - I s# I atl ftq I a-i I or I o I _l I z a I, z F d ) I i 38 I EFs t l*E t- i i I : rt Rch /o Rch loRch Figure 3 OF UU IJ 9F El =o 2e OPERATIONAL CHECK FOR CIRCUITS Power 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 on TUNER AUDIO P.C.B., fuses, and power transformer. (2) See TROUBLESHOOTING on Page 33. DC voltages are not correct. DC voltages are correct. START CONNECTION REPAIR -B+ + ! ro TONE CONTROL .- - tCheck the DC voltage across emitter resistor R529 (R531) (L ch) and lnsso (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. i I I I I I I ADJUSTMENT REPAIR - 15 - CONNECTION REPAIR ADJUSTMENT R EPAIR CHECK (. l. l. t Connect oscilloscope and V.T.V.M. to speaker terminal. l Connect 8O load to speaker output. Connect audio osc. to input of main amp circuit: C501s plus (+) side (L),1 and/or C502s plus (+) side (R) | lnput should be 500mV and output should be 13.3V (at 1 kHz) ) OSCILLOSCOPE VIV.M auDro osc. TUNER,AUDTO PC.3 en LoAo Figure 9 t-l l-c_ry 9 L ll 1yll.l rl.3 l_c I i p p i n_s _o f 9 lt! lt :,! 1u L y1: $i q g _i * * lnput level should be about 600mV to 1.0V.* (1) Check TR501, 503, 505, 509 (L) and TR502, 504, 506, 510 (R), (2) Check STEP 2 and STEP 3. (3) Check main amp. circuits. Output signal wave is not clipping symmetrically. NOT GOOD v Figure 10 Symmetrical clipping (balanced) of output signal iAJ;rit riprtlA, *oio oiC.IItnri SYMMETRICAL (jusi bcginninO to clip) WAVC. to produce 22 watts rated output iQn* t,f .1i .*n_Sq.q, * should be about 28.4 dB.* OUTPUT voltaqe (dB = 2u ros rNpurr *rtE-) (1) Check main amp circuits. (2) CheckSTEPs 1,2,3 and4. lnput level is not 500mV l2 dB. lnput level is at least 500mV t2dB for rated output power. Proceed to next section. -16 (+) Preamp Operation Check Connect audio osc. to PHONO input. connect oscilloscope and V.T.V.M. with decibel scale to TApE oUT jack. Set SE LECTOR switch to pHONO. Figure 11 (. l. . * RIAA Curve * loo n, - + 12.9 dB ( t r.Hr-odB ) r o rHz - -13.7 dB ) (1) (21 (3) Figure 12 2o , Auoo I x Check 1C301. Check C309, C31 1, R309, R31 1 ( L ch) and C310, C512, R310, R31 2 (R ch). Check PRE amp circuits. Equalization response at 100 Hz does not fallwithin + 12.g (RIAA) !2dB and 10 kHz does not fall within -13.7 (RtAA) t2 dB. Equalization response falls within + 12.9 (RIAA) 12 dB at 100 Hz and -13.7 (RIAA) !2dB at 10 kHz. OSCILLOSCOPE DtroooD!trtrtro o T- L 9 !15 _tl_P_lolo_ :. g,_u !.3! gy9T9 11.: REPAIR Proceed to next section. -11 - CONNECTION Tone Control Operation Check Connect audio osc. to AUX/TV input jack. Connect oscilloscope and V.T.V.M. to speaker terminal. Connect BO load to speaker output. Set SELECTOR switch to AUX/TV position. TAPE MONITOR: OFF MONO switch: STEREO LOUDNESS: OF F a a a a o a a oscrlloscoPE v_ T- v. M. auDr o osc. f- - iCfreck BASS action at 100 Hz. i t_ _ _ - _ _ _ _t * TONE CONTROL Curve* Figure 14 roo rk * AUDIO FREQUENCY (Hz) (1) Check bass control circuit on TUNER AUDIO P.C.B. (2) See TROUBLESHOOTING on page 35. Frequency response does not fall within 11012.5 dB. Frequency response falls within t 10 t2.5 dB. G +ro 3 l! 2o I Ia u -to E. t trtroooDtrUtrCo O sTA - ll5 Figure TONE CONTROL CURVE .lOO Hz EASS t ro kH, tneeLe ) R EPAIR -18- REPAIR REPAIR p!e+ r*Eii1t,et 1,tq tal * TONE CONTROL Curve (Figure 14)* (1) Check treble control circuit on TUNER AUDIO P.C.B. (2) See TROUBLESHOOTING on page 35. Frequency response does not