Sony-STSA50ES-tun-sm 电路图 维修手册.pdf

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1、ST-SA50ES US ModelSERVICE MANUAL FM STEREO FM-AM TUNER MICROFILM SPECIFICATIONS FM tuner section Frequency range87.5 108.0 MHz Antenna terminals75 , unbalanced Intermediate frequency10.7 MHz Sensitivityat 26 dB quieting (mono) 10.3 dBf, 0.9 V/75 at 46 dB quieting (stereo) 38.5 dBf, 23 V/75 Usable se

2、nsitivity (IHF)10.3 dBf, 0.9 V/75 S/Nat 40 kHz deviation 95 dB (mono), 86 dB (stereo) Harmonic distortionWIDE 0.008 % (mono), 0.02 % (stereo) NARROW 0.04 % (mono), 0.07 % (stereo) Frequency response15 Hz 15 kHz (0.2 dB) Separation65 dB at 1 kHz Selectivityat 400 kHz WIDE 80 dB NARROW 90 dB at 300 kH

3、z WIDE 45 dB NARROW 70 dB Outputat 40 kHz deviation 600 mV AM tuner section Frequency rangeAM :530 1,710 kHz (10 kHz step) Intermediate frequency450 kHz Usable sensitivity(with AM loop antenna) 200 V/m Signal-to-noise ratioAM :54 dB (50 mV/m, 1,050 kHz) Harmonic distortion0.3% (50 mV/m, 400 Hz) Sele

4、ctivity50 dB General Power requirements120 V, AC 60 Hz Power consumption13 W Dimensions16 15/16 3 7/8 13 3/8 in. (430 98 340 mm) Weight9 lbs. 1 oz.(4.1 kg) Supplied accessoriesAudio cord (1) AM loop antenna (1) FM wire antenna (1) Antenna adapter (1) Design and specifications are subject to change w

5、ithout notice. RadioFans.CN 收音机爱 好者资料库 2 1. GENERAL. 3 2. DISASSEMBLY 2-1.Panel, Front Assembly. 4 2-2.Display Board, Encoder Board, AC SW Board. 4 2-3.Panel Front . 4 3. TEST MODE. 5 4. ELECTRICAL ADJUSTMENTS.7 5. DIAGRAMS 5-1.Circuit Boards Location . 11 5-2.Printed Wiring Board Display Section .

6、13 5-3.Schematic Diagram Display Section . 15 5-4.Printed Wiring Board Tuner Section . 17 5-5.Schematic Diagram Tuner Section (1/2) . 19 5-6.Schematic Diagram Tuner Section (2/2) . 21 5-7.IC Pin Function . 23 5-8.IC Block Diagrams. 24 6. EXPLODED VIEW 6-1.Front Panel and Case Section . 25 7. ELECTRI

7、CAL PARTS LIST. 26 TABLE OF CONTENTS SAFETY-RELATED COMPONENT WARNING! COMPONENTS IDENTIFIED BY MARK ! OR DOTTED LINE WITH MARK ! ON THE SCHEMATIC DIAGRAMS AND IN THE PARTS LIST ARE CRITICAL TO SAFE OPERATION. REPLACE THESE COMPONENTS WITH SONY PARTS WHOSE PART NUMBERS APPEAR AS SHOWN IN THIS MANUAL

8、 OR IN SUPPLEMENTS PUBLISHED BY SONY. SAFETY CHECK-OUT After correcting the original service problem, perform the following safety checks before releasing the set to the customer: Check the antenna terminals, metal trim, “metallized” knobs, screws, and all other exposed metal parts for AC leakage. C

9、heck leakage as described below. LEAKAGE The AC leakage from any exposed metal part to earth ground and from all exposed metal parts to any exposed metal part having a return to chassis, must not exceed 0.5 mA (500 microampers). Leakage current can be measured by any one of three methods. 1.A commer

10、cial leakage tester, such as the Simpson 229 or RCA WT-540A. Follow the manufacturers instructions to use these instruments. 2.A battery-operated AC milliammeter. The Data Precision 245 digital multimeter is suitable for this job. 3.Measuring the voltage drop across a resistor by means of a VOM or b

11、attery-operated AC voltmeter. The “limit” indication is 0.75 V, so analog meters must have an accurate low-voltage scale. The Simpson 250 and Sanwa SH-63Trd are examples of a passive VOM that is suitable. Nearly all battery operated digital multimeters that have a 2V AC range are suitable. (See Fig.

12、 A) Earth Ground AC voltmeter (0.75V) 1.5k0.15F Fig. A. Using an AC voltmeter to check AC leakage. To Exposed Metal Parts on Set RadioFans.CN 收音机爱 好者资料库 3 SECTION 1 GENERAL 1POWER swtich (U) 2DISPLAY button 3ANTENNA button 4ASM button 5ANT ATT button 6IF BAND button 7FM MODE button 8BAND button 9MEM

13、ORY button Location of Controls 0CHARACTER button !MENU button !RETURN button !TUNE MODE button !TUNING/SELECT knob !ENTER button !NUMBER buttons !SHIFT button RadioFans.CN 收音机爱 好者资料库 4 SECTION 2 DISASSEMBLY Note : Follow the disassembly procedure in the numerical order given. 2-1. PANEL, FRONT ASSE

14、MBLY 2-2. DISPLAY BOARD, ENCODER BOARD, AC SW BOARD 2-3. PANEL, FRONT 3 Panel, front 2 Remove the two lower claws in the direction of the arrow. 1 While pressing the three claws in the direction of the arrow, pull the top of the panel slightly. 5 Three screws (BV3 8) 7 Panel, front assembly 2 Connec

15、tor (CNP701:TUNER board) 3 Connector (CNP702:TUNER board) 1 Connector (CNP951:TUNER board) 4 Lead with connector 6 Remove the two claws by pressing them in the direction of the arrow. 2 Knob (T) 4 Four screws (BV3 8) 8 Two screws (BV3 8) 6 DISPLAY board 9 AC SW board 1 Loosen the screw. 7 ENCODER bo

16、ard 3 Nut supplied with RV701 5 Remove the five claws. 5 SECTION 3 TEST MODE 1. Circuit Check Mode 1.Turn OFF the power. 2.While pressing 4 and MENU together, turn ON POWER . The items in the following table will be checked automatically in order every 2 seconds. Display Tuned IF Frq Sig Level Stere

17、o Items AST signal = LOW IF COUNT OK SI LEVEL 70dB ST signal = LOW FM RDS OK or NG OK or NG OK or NG AM OK or NG OK or NG NG IC251 NG, RV251 adjustments FE101, IC251 NG, or IF count buffer amp (Q251, Q401) NG IC221 NG, RV221 adjustments IC301 NG, RV301 adjustments DISPLAY 6 NOTE : The preset data wi

18、ll be erased when this test mode is used. Therefore, take down the data before setting this mode and preset the data again after completing operations in this mode. 2. Display Tube Check and KEY Check mode NOTE : Do not perform this check mode when replacing display tubes or excepting when replacing

19、 a microcomputer. 1.Turn OFF the power. 2.While pressing 1 and MENU together, turn ON POWER . 3.While continuously pressing 1 and MENU together, check the following. Indication test pattern * The indication test patterns from 2 to 5 are indicated on only even grids. The display changes every 1 sec.

20、4.Release 1 and MENU . The KEY CHECK mode will be set. 5.All key numbers will be displayed. Key Number : 24 6.Each time the key is pressed, the key number will be counted down. Each key will be counted only once, at the first time. 7.When all keys have been pressed, the process will end. NOTE : As c

21、ontents of the Factory Preset will be written into memory after completing this check mode, delete contents of memory according to 4. Forced RESET. 3. Entering the Factory Preset (In case perform just to write memory of the Factory Preset.) 1.Turn OFF the power. 2.While pressing 3 and MENU together,

22、 turn ON POWER . 4. Forced RESET (Used to delete the contents of Factory Preset when it is written into the preset memory.) Clears all the RAMs and sets the initial state 1.Turn OFF the power. 2.While pressing 5 and MENU together, turn ON POWER . 5. How to select the frequency steps of the AM band 1

23、.9kHz step : while pressing 9 , turn ON POWER . 2.10kHz step : while pressing 0 , turn ON POWER . Microcomputer version indication (1 sec)All light up “7F”Dot area only “60”Dot area only “7E” Dot area only “3D”Dot area only “5F” 1 7F2 603 7E4 3D5 5F 7 SECTION 4 ELECTRICAL ADJUSTMENTS Precautions in

24、Repairing If the front end unit fails, it is difficult to repair the inner circuits, so replace the entire front end unit. Standard Setting of FM Stereo RF Signal Generator. FM SECTION0dB = 1V STEREO STANDARD SIGNAL MONAURAL STANDARD SIGNAL Carrier frequency: 98MHz Modulation: Audio 1kHz Main channe

25、l (L+R) : 33.75kHz deviation Sub channel (LR): 33.75kHz deviation Pilot: 7.5kHz Deviation Carrier frequency:98MHz Modulation:Audio 1kHz 75kHz deviation FM Discriminator ADJUSTMENT (NULL and MONO Distortion Adjustment) Setting: IF BAND : WIDE Procedure: 1.Tune the set to 98 MHz. 2.Adjust T252 for 0V

26、reading on the VTVM. . NULL 3.Adjust T253 for a minimum reading on the distortion meter. . MONO Distortion (THD) 4.Repeat the adjustments of 2 and 3 several times. Note : When replacing the ceramic filter, perform this alignment. set FM RF Stereo signal generator 1kHz highpass filter distortion mete

27、r FM ANTENNA (75)LINE OUT set FM RF Stereo signal generator 1kHz highpass filter distortion meter FM ANTENNA (75) (at 75 open) Modulation : Monaural Standard signal Output level : 6mV (76dB) LINE OUT VTVM (DC range)TP251 NULL terminal 8 Stereo Level Adjustment Setting: IF BAND : WIDE Procedure: 1.Tu

28、ne the set to 98 MHz. 2.Adjust RV251 so that the “STEREO” indicator goes on. Narrow Gain Adjustment Setting: IF BAND : NARROW Procedure: 1.Tune the set to 98 MHz. 2.Set IF BAND switch to the NARROW position. 3.Adjust RV231 so that the “STEREO” indicator goes on. FM Meter Level Adjustment Setting: IF

29、 BAND : WIDE Procedure: 1.Tune the set to 98 MHz. 2.Press DISPLAY key to display the digital signal, then adjust RV221 to be displayed as “SIG 70dB”. set FM RF Stereo signal generator FM ANTENNA (75) Modulation : Stereo Standard signal Output level : 32V (30dB) (at 75 open) Front End IFT/STEREO Dist

30、ortion Rate Adjustment Setting: IF BAND : WIDE Procedure: 1.Tune the set to 98 MHz. 2.Remove the top cover of the front end (FE101). 3.Adjust IFT1 of the front end (FE101) to put the noise up-and- down and symmetrically on the waveform of the oscilloscope. 4.Adjust the front end (FE101) IFT1 to mini

31、mize the STEREO distortion rate. 5.Attach the removed top cover of the front end (FE101) as it was. Note : Do not turn more than a half turn from the core position which is adjusted on the front end IFT adjustment. Narrow THD Adjustment Setting: IF BAND : NARROW Procedure: 1.Tune the set to 98 MHz.

32、2.Set IF BAND switch to the NARROW position. 3.Set SSG output level to 80dB. 4.Adjust RV232 for a minimum reading on the distortion meter. set FM RF Stereo signal generator FM ANTENNA (75)LINE OUT Modulation : Monaural Standard signal Output level : 2.2V (7dB) (at 75 open) + Oscilloscope set FM RF S

33、tereo signal generator FM ANTENNA (75)LINE OUT Modulation : Stereo Standard signal Output level : 6mV (76dB) (at 75 open) distortion meter 1kHz highpass filter set FM RF Stereo signal generator FM ANTENNA (75)LINE OUT Modulation : Stereo Standard signal Output level :6mV (76dB) (at 75 open) distorti

34、on meter 1kHz highpass filter set FM RF Stereo signal generator FM ANTENNA (75) Modulation : Stereo Standard signal Output level : 3mV (76dB) (at 75 open) set FM RF Stereo signal generator FM ANTENNA (75) Modulation : Stereo Standard signal Output level : 32V (30dB) (at 75 open) 9 Stereo Separation

35、Adjustment Setting: IF BAND :NARROW(NARROW SEPARATION) WIDE (WIDE SEPARATION) Procedure: 1.Set IF BAND switch to the NARROW position. L-CH Stereo separation : A B R-CH Stereo separation : C D The separations of both channels should be equal. set FM RF Stereo signal generator FM ANTENNA (75)LINE OUT

36、VTVM Modulation : Stereo Standard signal Output level : 6mV (76dB) (at 75 open) FM stereo Signal generator Output channel L-CH R-CH R-CH L-CH Level meter connection L-CH L-CH R-CH R-CH Level meter reading (dB) A B IF BAND WIDE : Adjust RV301 for minimum reading on VTVM IF BAND NARROW : Adjust RV302

37、for minimum reading on VTVM C D IF BAND WIDE : Adjust RV301 for minimum reading on VTVM IF BAND NARROW : Adjust RV302 for minimum reading on VTVM 10 AM SECTION Setting: BAND : MW AM Meter Level Adjustment Setting: Carrier frequency : 1,050kHz Modulation: 400Hz, 30% modulation Procedure: 1.Set AM RF

38、signal generator so that the AM antenna input level becomes 74dB/m. 2.Adjust RV402 so that 1 to 10 indication bars light up on the signal meter. Adjustment Location : AM RF SSG loop antenna set loop antenna (Supplied accessories) 60 cm AM antenna terminal 30% amplitude modulation by 400 Hz signal Fi

39、eld strength dB (V/m) =SSG output level dB (V/m) 26 dB. FE101 RV402 AM Meter Level Adjustment RV232 Narrow THD Adjustment RV251 Stereo Level Adjustment T252 FM Discriminator Adjustment (Null and Mono Distortion Adjustment) RV221 FM Meter Level Adjustment IFT1 Front end IFT/ Stereo Distortion Rate Ad

40、justment RV231 Narrow Gain Adjustment IC221 IC251 IC401 TP251 RV301 wide Separation Adjustment RV302 Narrow Separation Adjustment IC301 T253 (Distortion) (Null) 11 12 SECTION 5 DIAGRAMS AC SW board DISPLAY board ENCODER board TUNER board 5-1. CIRCUIT BOARD LOCATION THIS NOTE IS COMMON FOR PRINTED WI

41、RING BOARDS AND SCHEMATIC DIAGRAMS. (In addition to this, the necessary note is printed in each block.) Note on Schematic Diagram: All capacitors are in F unless otherwise noted. pF: F 50 WV or less are not indicated except for electrolytics and tantalums. All resistors are in and 1/4 W or less unle

42、ss otherwise specified. : internal component. 2 : nonflammable resistor. C : panel designation. Note: The components identified by mark ! or dotted line with mark ! are critical for safety. Replace only with part number specified. U : B+ Line. V : B Line. H : adjustment for repair. Voltages and wave

43、forms are dc with respect to ground under no-signal (detuned) conditions. no mark : FM Voltages are taken with a VOM (Input impedance 10 M). Voltage variations may be noted due to normal produc- tion tolerances. Waveforms are taken with a oscilloscope. Voltage variations may be noted due to normal p

44、roduc- tion tolerances. Circled numbers refer to waveforms. Signal path. F: FM f: AM Note on Printed Wiring Boards: X : parts extracted from the component side. : internal component. b : Pattern of the rear side. Waveform 1 IC 701 ! XTAL 4.19MHz 4Vp-p ST-SA50ES 12 A B C D E F 34567891011121314 13 14

45、 5-2. PRINTED WIRING BOARD DISPLAY SECTION Refer to page 11 for Circuit Board Location. 16 ECP700 Ref. No.Location D701E-13 D702D-13 D703D-11 D705E-11 D707E-12 IC701D-8 IC702E-10 Q701E-11 Semiconductor Location ST-SA50ES 15 16 5-3. SCHEMATIC DIAGRAM DISPLAY SECTION Refer to page 12 for waveform. Ref

46、er to page 23 for IC Pin Function. 1 16 The components identified by mark ! or dotted line with mark ! are critical for safety. Replace only with part number specified. ST-SA50ES 12 A B C D E F G H 3456789101112131415 17 18 5-4. PRINTED WIRING BOARD TUNER SECTION Refer to page 11 for Circuit Board L

47、ocation. 16 R220 Semiconductor Location Ref. No.LocationRef. No.Location D221G-2 D251F-8 D301C-9 D401B-7 D402E-6 D901C-4 D902C-4 D903C-4 D904C-4 D905D-4 D906G-11 Ref. No.Location IC221G-2 IC251G-6 IC301C-10 IC401D-7 IC901D-5 Q200G-3 Q201G-3 Q202G-4 Q203G-4 Q204G-4 Q231G-4 Q232F-4 Q233F-4 Q234G-5 Q235F-5 Q236G-5 Q237G-5 Q251G-8