Realistic-STA78-rec-sm 电路图 维修手册.pdf

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1、ruLtsfiC Serulce STA.78 AM /FM STEREO Catalog Number : RECEIVER 31-2077 cusToM MANUFACTURED FoB RADIo sHACK In DMSIoN 0F TANDv conponAloN RadioFans.CN 收音机爱 好者资料库 (1) (21 (3) (4) (5) (6) (71 (B) (e) ( 10) (11) (121 ( 13) (141 ( 15) ( 16) (171 ( 1B) ( 1e) (20) (211 CONTENTS ELECTRICAL PERFORMANCE SPEC

2、I FICATIONS DISASSEMBLY INSTRUCTIONS . PAGE 3-5 BLOCK DIAGRAM DIAL STRINGING LEVEL DIAGRAM ALIGNMENT INSTRUCTIONS TROUBLESHOOTI NG BRIEF DESCRIPTION OF PROTECTOR CIRCUIT IC all units should be able to approximate these - some will exceed and some may drop slightly below these specs. Limit Specs repr

3、esent the absolute worst condition which still might be considered acceptable; in no case should a unit perform to less than within any Limit Spec. 2. DISASSEMBLY INSTRUCTIONS 1) To remove Chassis f rom wooden cabinet. Turn the cabinet upside down and re- move the six screws from the bottom cabinet.

4、 (Figure A) 2) Removal of Front Panel. a) Remove the chassis from wooden b) Pull out the Main Chassis. c) Remove the two screws from the top d) Remove knobs and pull off panel. FigureA cabinet as described in 1). and three screws from the bottom of (F igure B1 , B2l the Front Panel. 3)To remove Rear

5、 Panel from chassis. Remove the four screws from the Rear Panel. (F igure C) Figure B1Figure 82 -5- a E U Y U II a .I ri -;- 1 E 5 9 t! i -N I I O _.1 a u a Eo =o oi doo ll 9 3 e- d LF ,E;- o? 50 i ij* i :33 or;l -o EE i oo z ! E;I =Pg 66 =N =E =o EE = EF 3. BLOCK DIAGRAM -6- 4. DIAL STRINGING DIAGR

6、AM *START WITH CAPACITOR SET AT MINIMUM. PLATES FULLY OPEN (UNMESHED). *Pointer Position : HIGH END 5. LEVEL DIAGRAM F I AUDIO FREQIJENCY. lkHz -7- 6.ALIGNMENT INSTRUCTIONS AUDIO CIRCUIT ADJUSTMENT,/CHECK EOUIPMENT REOUIRED 1. DC Voltmeter 2. Audio Oscillator 3. Oscilloscope 4. AC Voltmeter Note: Ma

7、intain voltage at 12O volts AC, 60 Hz (UL, CSA) (240 volts, 50 Hz AC for Australian models). *Set SELECTOR Switch to AUX. *Set MODE Switch to STEREO. See P.C.B. illustration for alignment points/adjustments. For location of connection points and trimmer resistors, see P.C.B. view. (-25mV to+25mV) Fi

8、gure 6 Oscilloscoge (Shorled OutpuiCondition) (Normol Condiiion) Figure 5 MAIN AMP ADJUSTMENT STEPADJUSTMENTEOUIPMENT CONNECTIONAUDIO FBEO. LEVELADJUSTMENT 1 Check Balance by measuring DC voltage across Output Termi- nal of L and R chan- nel. DC Volt Meter See Figure 1No signalDC voltage should be l

9、ess than 25 mV 2 ldling current adjust- ment DC Volt Meter See Figure 2.No signalAdjust so voltage across Emitter resistors R633 anc R634 is 5 mV (8 ohm load). VR601 VR602 Figure CHECKING LIMITER CIRCUIT STEPADJUSTMENTEOUIPMENTCONNECTIONAUDIO FREOSETTING LEVEL 1 Audio Osc. V.T.V.M. Oscilloscope See

10、Figure 3.1000 HzVOLUME: Max. BASS, TREBLE BALANCE: center Adjust input to AUX to get out- put level at just the clipping point (4 ohm load) Figure 4. 2 Check the limiter ci rcu i t. Audio Osc. V.T.V.M. Oscilloscope See Figures 3, 5. 1000 HzSame as aboveCheck that output dropt to a square wave across

11、 R633 (R634) when out- put speaker termi- nals are shorted. See Figure 6. 4ohm L.od ,A-. -(yo c - +) AUDIO Osc. AUX SrA-79 ( rooHz) Figure 3 Oscilloscope 1J -8- AM RF I ti6 6d De , - | 6G_=_j r2or STEP SIGNAL GENERATOR COUPLING SIGNAL GENERATOR FREOUENCY DIAL SETTlNG INDICATORADJUSTMENTREMARKS 1 Con

12、nect standard loop ANTENNA to Signal Generator and radiate signal into the AM Fer- rite Antenna. See Figure 8. 455 kHz (400 H2,30% mod.) Point of non-inter- ference (near 600 kHz) Scope and, AC Volt- meter to TAPE OUT Jack. r202 T203 (AM IFT) Adjust for maxi- mum reading on meter. 2 Same as STEP 1.5

13、10 kHz (400 H2,30% mod.) Tuning Gang fully closed. Same as STEP 1. L2O3 (AM OSC Coil) Adjust for maxi- mum reading on meter. Refer to Figures 7 and 8. 3 Same as STEP 11650 kHz l4OO H2,30% mod.) Tuning Gang fully opened. Same as STEP 1. TC105 (AM OSC Trimmer) Adjust for maxi- mum reading on meter. Re

14、fer to Figures 7 and 8. 4 Same as STEP 1600 kHz (400 H2,30% mod.) 600 kHzSame as STEP 1. L8O2 (AM ANT. Coil) Adjust for maxi- mum reading on meter. Refer to Figures 7 and 8. 5 Same as STEP 11400 kHz (400 Hz, 30% mod.) 14OO kH,zSame as STEP 1. TC104 (AM ANT. Trimmer) Adjust for maxi- mum reading on m

15、eter. Refer to Figures 7 and 8. 6Repeat STEPs 4 and 5 until no further change is noticed. 7 Same as STEP 11000 kHz (400 kHz,30% mod.) Output level to 100 mV/m 1000 kHzAM Signal Meter on Set. VR201Adjust so the Meter Pointer on Receiver is at about 85% of full scale. 2 -_.4 AM BAR ANTENNA (6ocm) L/ l

16、/_ /ffi wfl FM RF L, !. i6 E )L( R655 (R636 ) -Fr 6 rn6rs + :rR6r4) I ) oo rl (06ro)J F B D6t3(D6t4) -16- 8. IC Bef. No. Value (F) illin Tolerance %l Material c247 c248 c249 c250 c251 c252 c253 c254 c255 c268 c269 c270 czl1 c272 c273 c274 c256 c257 c258 c259 c260 c261 c262 c263 c264 c265 c266 c267 c

17、275 c276 czt7 c301 c302 c303 c304 c305 1p I z.zp I 33oP I rop I 0.47 1t I I 220P I 0.47 p I 0.01 p I 220 rt I lop 680 P 0.047 p 0.0018 p 0.0018 p 1500 P 4.47 p 0.22 p 0.1 p 0.02 p 0.47 p 0.47 p 0.0018 p | 0.0018 p I 0.47 p 10.47 p l rro, I zzop I o.+z u I o.o, u I 1470 u lrrou I l+zop l+zop I o.zzp

18、I o.zzu lMp 50 25 50 16 50 50 50 50 16 16 50 50 50 50 50 25 25 50 50 50 50 50 50 50 50 50 50 50 50 16 t6 50 50 25 25 25 +75 -10 +75 -10 r5 +50 -10 +75 -10 t5 +75 -10 110 +50 -10 +50 -10 rb +10 tl0 *10 +5 *-2A r20 *10 +80 -20 +75 -10 +75 -10 r10 *10 +75 -10 +75 -10 +5 r5 +75 -10 +75 -10 +50 -10 +50 -

19、10 rb +5 r.20 *.20 +50 -10 Electrolytic Electrolytic Ceramic Electrolytic Electrolytic Ceramic Electrolytic Mylar Electrolytic Electrolytic Polystylene Mylar Mylar Mylar Polystylene Aluminum Aluminum Mylar Ceramic Electrolytic Electrolytic Mylar Mylar Electrolytic Electrolytic Ceramic Ceramic Electr

20、olytic Electrolytic Electrolytic Electrolytic Ceramic Ceramic Tantalum Tantalum Electrolytic Bef. No. Value (F) if Tolerance t%t Material c306 c307 c308 c309 c310 c31 1 c312 c313 c314 c31 5 c401 c402 c403 c404 c501 c502 c503 c504 c505 c506 c507 c508 c509 c510 c51 1 c512 c513 c514 c51 5 c51 6 c517 G5

21、1 I c519 c520 c521 c522 c523 c524 c525 47 tt l0p 10p 2000 P 2000 P 0.0068 p 0.0068 p 1tt ltt 330 p 330 P 330 P 0.01 p 0.01 p 0.068 p 0.068 p 1tt 1tt 220P 220P 47 tt 47 tt 10p lop 3.3,.t 3.3 p I()() P 100 P 0.001 2 p 0.0012 p 0.033 p 0.033 p 0.033 p 0.033 p 1p 1 p 25P 25P 1p 25 25 25 50 50 50 50 25 2

22、5 35 50 50 50 50 50 50 35 35 50 50 25 25 16 16 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 +50 -10 +50 -10 +50 -10 t5 r5 110 110 +20 *20 +50 -10 *.b *b r10 r10 r10 110 *-20 x20 *.5 r5 +50 -10 +50 -10 +50 -10 +50 -10 +75 -10 +75 -10 r5 rb tl0 110 tl0 +10 +10 *.10 +15 -10 +75 -10 *5 r5 +75 -10 Electr

23、olytic Electrolytic Electrolytic Polystylene Polystylene Mylar Mylar Tantalum Tantalum Electrolytic Polystylene Polystylene Mylar Mylar Mylar Mylar Tantalum Tantalum Ceramic Ceramic Electrolytic Electrolytic Electrolytic Electrolytic Electrolytic Electrolytic Ceramic Ceramic Mylar Mylar Mylar Mylar

24、Mylar Mylar Electrolytic Electrolytic Ceramic Ceramic Electrolytic F -25- Hef. No. Value (F) Voltage (v) Tolerance t%l Material c526 c527 c528 c529 c601 c602 c603 c604 c605 c606 c607 c608 c609 c61 0 c61 1 c612 c61 3 c61 4 c61 5 c61 6 c61 7 c61 I c61 I c620 c621 c622 c623 c624 c625 c626 c701 c702 c70

25、3 tp 220 p 0.02 p 220 p 0.0022 p 0.0022 p 2.2 p 2.2 p 56P 56P 5P 5P 47p 47p 224 p 220 p 100 p 100 p 0.022 p 0.422 p 0.022 p 4.022 p 0.0047 p 0.0047 p 0.0047 p 0.0047 p 0.047 p 0.047 p 0.022 p 0.022 p 0.04 p 0.04 p 0.04 p 50 35 50 35 50 50 50 50 50 50 50 50 10 10 35 35 35 35 50 50 50 50 50 50 50 50 5

26、0 50 50 50 50 50 r00 +75 -10 +50 -10 +80 -20 +50 -10 +.10 *.10 +75 -10 +75 -10 r5 r5 r5 a5 +50 *10 +50 -10 +50 -10 +50 -10 +50 -10 +50 -10 +80 -20 +90 -20 +80 -20 +80 -20 r10 i10 i.l0 n10 +80 -20 +80 -20 *10 r10 +80 -20 +80 -20 +80 -20 Electrolytic Electrolytic Ceramic Electrolytic Mylar Mylar Elect

27、rolytic Electrolytic Ceramic Ceramic Ceramic Ceramic Electrolytic Electrolytic Electrolytic Electrolytic Electrolytic Electrolytic Ceramic Ceramic Ceramic Ceramic Ceramic Ceramic Ceramic Ceramic Ceramic Ceramic Mylar Mylar Ceramic Ceramic Ceramic Hef . No. Value (F) Voltage (v) Tolerance (%) Materia

28、l c704 c705 c706 c707 c708 c709 c710 c7 11 c712 c713 c714 c80 1 c802 c803 c804 c805 c901 c902 0.04 p 0.04 p 0.04 p 1000 p 1000 p 470 p 220 p 470 p 470 p 220 tt 220 p 0.01 p 6800 p 6800 p 0.01 p (UK or M 0.01 p (MS Typt 0.01 p 1p 22p 100 100 100 50 16 16 16 50 35 16 35 50 35 35 125 R Type) 125 r) 50

29、50 10 +80 -20 +80 -20 +80 -20 +50 -10 +50 -10 +50 -i0 +50 -10 +50 -10 +50 -10 +50 -10 +50 -10 +80 -20 +50 -10 +50 -10 +80 -20 +80 -20 +80 -20 +75 -10 +50 -10 Ceramic Ceramic Ceramic Electrolytic Electrolytic Electrolytic Electrolytic Electrolytic Electrolytic Electrolytic Electrolytic Ceramic Electr

30、olytic Electrolytic Ceramic (U L) Ceramic (c.s.A.) Ceramic Electrolytic Electrolytic CERAMIC FILTERS Ref. No.Description B/S Part No. Mfrs Part No. cF201 cF202 FM Ceramic Filter (sEF-10.7MA-8) FM Ceramic Filter (sEF-10.7MA-8) cA-7536 cA-7536 P-140030 P-140030 cotLs 1 -AM, 2- FM, 3-PHONO,4-AUx, C-COM

31、MON. (2) Ps-1 - Ps-2: POWER SWITCH (3) Sp-l - Sp-4: SPEAKER SELECTOR SWITCH. POSITION: 1 -OUT, 2- A,3-A, REV. 4 -8,5-A+ B (4) ALL RESISTANCE VALUES ARE INDICATED IN ,OHM,. (K_ 103 OHM, M _ 106 OHM)i ToNE AMP P, c, B (5) ALL CAPACITANCE VALUES ARE INDICATED lN pF. (P - 1O-6pF) (6) ( VALUES IN MAIN AM

32、P STAGE ARE USED FOR C,S,A. MODELS ONLY. (7 ALL VOLTAGES ARE MEASURED TO CHASSIS GROUND WITH A VOLTMETER (10 K OHM/V (8) VOLTAGES ARE MEASURED UNDER TWO CONDITIONS: WITH NO INPUT AND AT 22W 11 kHz) OUTPUT POWER (INSIDE PARETHESIS). -36- *9 ;i ;q TF5O2 2$15il n60? txl; EIE I C 20 HAil 2ll IRrcJ.T8204

33、 2SC929,2 ufl ezz.loo ;?92_.,1293_ F32t 6A0 c309 c3 2000P.0068 , R529 B B,s R505 J0h htlsEl-l#;IJJ I I f Sf-T- i : l+10./25 560 calo cal2 I - | ,llulBf 2oooP oo58 I L_ r*.orrr.r_l 5a :H 1 EEi W!, I FRONT END AM,ry_ _ ./ l,i It ti I T R?6 :f202 c .U _U L .l I Rl L- I I Rl a + E LU u I +l RI I c237 L

34、.o4 * METER LAMP l2v 0_15a 5s- l l2v 0.15a ,4 PROTECTOR - t- l 250V 3A swci P5-l AC OUT LEI UNSWIIHEO I I IC 201 HA112t1 l: Tl t; /hD R213 ; CH P.C.B iiolr*-fFr. o- - * ;,Giliilili-_l I rFoog 2sB56o TF613 zsBsog TF 6.7 2sAE59 | I 0611 r, Irt73N I FP tDC POWER SUPPLY li+:+* IBJJ-J ,l n ,l Yl I ttr l,

35、r.*,* I neoz csol iil 5a PEI I I I ! nszo a7t -37 - | _ rR6ro 2sBE6o TR614 zsBsog rR6lE ?sAE59 21. EXPLODED VIEW I E-u G : -oG i /t Y/ F -39- T RADro sHAcr( EI DrvrsroN oF rANDy coRpoRAroN U.S.A.: FORT WORTH, TEXAS 76102 CANADA: BARRIE, ONTARIO L4M 4W5 AUSTRALIA TANDY CORPORATION BELGIUMUK 280 316 VICTORIA ROAD RYDALMERE, NSW.2116 PARC INDUSTRIEL OE NANINNE 5140 NANINNE BILSTON ROAI, WEONESBURY WEST MIDLANDS WSlt 7JN 11 A7Printed in Japan