Realistic-STA21-rec-sm 电路图 维修手册.pdf

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1、STA.21 AM /FM STEREO RECETVER Catalog Number : 31 -2071 cusT0M MANUFACTURED FOR RAD|0 SHACK ln DMS|0N 0F TANDY C0RP0RAT|0N J RadioFans.CN 收音机爱 好者资料库 (1 ELECTRICAL PERFORMANCE SPECIFICATIONS . 3 - (2 DISASSEMBLY INSTRUCTIONS . (3) BLOCK DIAGRAM (4) ALIGNMENT INSTRUCTIONS .,. 7 - (5) TROUBLE SHOOTING

2、. . , 12 - (6) DIAL STRINGING DIAGRAM (7) IC :; 55 7.1 70 45 6 30 1.0 0.8 t 500 + 500 300 - 800 30 0.1 750 + 2.5 dB : Frequency Response must meet the 75 1-usec.De-emphasis for UL and C.S.A. Approved Models (50 p sec.De-emphasis for European and Australian Models). -3- RadioFans.CN 收音机爱 好者资料库 FM MPX

3、 Stereo lndicator ON Point Separation at 1 mV 100 Hz 1 kHz 10 kHz Stereo Distortion 1 mV 1 kHz 38 kHz Rejection SCA Rejection AUDIO SECTION lnput lmpedance PHONO MAG. AUX Output Power at THD 1% 8 ohms Both Channels Driven at 1 kHz Power BandwiE oo I o ; o o o d o d o $ o ;o r 2 z z z z Zz F z- O-O 6

4、HH do OF E )z !d 1A OI ri OF -z zo ou = !2o rH r l =E o L = E u = o 2 2t U FF = !2 ?3 uF :5 =*L o9 _c -6- 4. ALIGNMENT INSTRUCTIONS MAIN AMPLIFIER AND RESET CIRCUIT ADJUSTMENT/CHECK NOTE o Maintain line voltage at 120 volts. (UL, C.S.A.) (Use 220/240 VAC For European stretch or squeeze) Adjust for m

5、aximum reading on meter. 9 Same as above106 MHz106 MHz Tune to Signal TC 101 (FM ANT Trimmer) TC 102 (FM RF Trimmer) 10Repeat STEPs (8) and (9) until no further improvement is noticed. 11 Same as STEP (8) ANT. input: 1 mV 98 MHz98 MHz Tune to Signal T110Adjust for maximum reading on meter. 12 Same a

6、s STEP (8) ANT. input: 100 mV VR1OlAdjust so the Meter Pointer on Receiver is full scale. -9- FM SIGNAL GENERATOR FM ALIGNMENT SET-UP 3OOO DUMMY FM ANT Sweep Gen- FM STEREO ALIGNMENT Equipment Required 1. Stereo Modulator . . . . 2. FM Signal Generator . . 3. Audio Generator 4. AC Voltmeter 5. Oscil

7、loscope 6. Distortion Meter 7. Frequency Counter Note: See P.C.B. illustration for alignment/test points. Preliminaries Set SELECTOR switch to FM STEREO. MULTIPLEX a (D3oe) I i tI OUT PUT Lor R MAIN AMP CIRCUIT - 11- 5. TROUBLE SHOOT!NG SymptomCause/Remedy 1) No output.1) Faulty AC power cord. Repla

8、ce the cord. 2) Defective power switch. x Replace the switch. 3) Broken wire in the power transformer. * Replace the transformer. 2) Pilot lamp does not light.1) Broken lamp. x Replace the lamp. 2) Open in the power transformer tertiary winding. Replace the power transformer. 3) Pilot lamp lights bu

9、t no speaker ouptut.1) Defective capacitor C326or C327. * Replace the defective capacitors). 2) Defective diode D 301, 302, 303 or 304. x Replace the defective diode(s). 3) Defect in the power transformer secondary winding. * Beplace the power transformer. 4) Blows fuse.1) Defective doide D 301-304

10、in the rectifier circuit. x Replace the defective diode(s). 2) Short-circuit in the rectifier circuit. x Remove the short. 3) Short-circuit in power transistor circuitry TR 311-314. * Repair circuit and,/or Replace the defective transistor. 5-1) No output one channel with VOLUME at maximum and BALAN

11、CE at center, when a test signal is applied to the terminal of non-operating channel of the BALANCE control R 249. 1) Defective transistor TR 205, 206 or TR 301-314. x Replace the defective transistor(s). 2) Defective resistor or capacitor of TONE or MAIN AMP circuit. * Replace the defective part(s)

12、. 5-2) No output when a test signal is applied to the input terminals. 1) Defective transistor, resistor or capacitor of PRE AMP circuit. * Replace the defective part(s). 2) Defective MONO/STEBEO or TAPE MONITOR switch. x Replace or repair the switch(es). 3) Defective Selector switch, * Replace the

13、Selector switch. 6) Speaker works normally but headphone does not work. 1) Defective R zl01 (left) or R 4O2 (right). x Change it. 7) All the inputs work normally except AUX input. 1) Poor contact in AUX input jack. x Replace or repair it. 2) Defective resistor R 501, 502, 503 or 5(X. * Replace it. 3

14、) Poor contact in selector switch. * Repair or replace the switch. 8) PHONO input no operative.1) Poor contact in PHONO input jack. x Repair or replace it. 2) Faulty selector switch. x Repair or replace the switch. - 12- Symptom Cause/Remedy 9) TAPE OUT inoperative. 1) Poor contact in TAPE OUT ouput

15、 jack. *. Repair or replace it. 10) No AM or FM. (TUNER B + voltage is not l1-12 V). 1) Broken tertiary winding in the power transformer. * Replace the transformer. 2) Defective diode D 305,306 or D314. * Change the defective diode(s). 3) Faulty capacitor C 3n,324, or 325. x Change it. 4) Defective

16、resistor R 337. * Replace the resistor. 5l Zener diode D 314 defective. * Replace the diode. 6) Short circuit in TUNER B + circuit. * Remove the short. 7) Poor contact in selector switch. * Repair or replace it. 11) No FM. 1) Poor contact in selector switch. x Repair or replace it. 2) Defective resi

17、stor or capacitor of FM Tuner circuit. * Replace the defective part(s). 3) Transistor, diode, lFT, resistor or capacitor of FM Tuner l BCE 2SD 330 2SC 288 2SC 790 GDS l: (rooor) =r./ 2SK 19 m ilil GDS e 2SK 41 ffiffi LA 3350 ilil ECB ( ooo ) _/ 2SC 945 2SC 1047 2SC 900 2SC 1359 2SC 923 2SA 539 2SC 6

18、44 2SA 561 2SC 815 2SA 495 25C734 2SC828 2SC 829 2SC 930 m ililil GAK e M 21C 2SF 657 -15- 8. AM/FM TUNER, IF I ,t: ,: :ii LN Ia 9:llt iillt ,.=7Y4 .4tiiiarrr:u:r.rt1f , t: II -_l F *1:i .i $* 1q ,P :1 :! ; l. * , i; ry , rffi :?.* -17- 10. MAIN AMP ;t t- I _- rrneo,.lF - 3 2: o.o. f r.Bx 3 I t- or

19、25C1571 Its ll IL rR206 2SC900 TR204 2SC823 L_ :i,;3,?9f _ _ i ) SA -SA.6 FUNCION SWI: 2) SB I,SB2 SPEAKER SEL: 3 ) ALL RESISTANCE VALUES A r ) ALL CAPAC TANCE VALUES 5I * VA|UE MAY VARY FRC! _1_- -32- E3 lr+ a .l+ ,fr ;) 2SC930( 0.E ) 2SC93O(0.E) TR305 rR30? TR3ll, TR3l3 2SA539 25C8r5 2SD238 or 25A

20、a95 or 2SC734 or 25C790, 250330 rR303 25C8t5 _l 250288 TR3l0 25A539 or 2Sa790,250330 N OTE 5A.-5A 6 FUNCIION SWIICH 1-AM, 2.FM, 3.PHONOJ 4-AUX 2) SB,SB-2 SPEAKER SELECTOR SWIICH .OFF, 2-A, 3-8, 4 A+B 3) ALL RESSTANCE VALUES ARE INOLATED IN OHM(K=IO3OHM, M=106OHM) 4) ALL CAPACIANCE VALUES ARE NDICATE

21、D IN UF ( P=IO 6 ). 5) * VA|UE MAY VARY FROM UN TO UNI FOR OPTMUM PERFORMANCE. AD PHONE JACK ! a?29 t./25 0 307 c3r9 224/ 25 AC OUTLET 2.2M LED -l Lch REMOTE SPEAKER Rch REMOTE SPEAKER MA N SPEAKEA sw A. -_ -_ )LCn ONI Y u -l I MAIN SPEAKER .-l rF I . I ,-.l h )Rcn5) n.n 0.02 T I t232 i 0-0012 Lczzt

22、 rTliBi c234 0.0r -33- 16. EXPLODED VIEW 4 ffi_ 666 ru g /ro / r/ _/_ /t / i _ *-v-/ MO V/it /:H - 34- 1 -n.*.: ) . / /i=X: _ t,/ x )K/ /rr U, -35- ! V RADro sHAcK EI DrvrsroN oF rANDy coRpoRArroN U.S.A.: FORT WORTH, CANADA: BARRIE, ONTARIO, I I i I I i 1l tl I I I I i I I I I Ji i .i I :, TEXAS 76102 CANADA L4M 4W5 AUSTRALIA TANDY CORPORATION BELGIUMU-K 280 316 VICTI)RIA ROAD RYDALMERE, N.S.W. 2116 PARC INDUSTRIEL DE NANINNE 5140 NANINNE BITSTON ROAD WEONESBURY, STAFFS WS1O 7JN 746 Printed in Japan