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1. 100 Qd p mH R29 33 40 55 VR5 VCO ADJ 05 05009 100k o ah 68k S2 DUPLICATE ASX 134 TN S3 ADAPTOR ASX 130 4 MODE ASK 152 4 ADAPTOR IN ADAPTOR OUT rT 4 TUNER Assy GWE I32 aser 1Sv69 25 530 j 2 y 1 u SWITCH Ass y 1 2 AMP Ass z NETTO E E cas K Ni Q6 7 1201 y TONE AMP Ass y R SPEAKER TERMINAL x J VR2 TREBLE 1 50 OFF _ _ ot a GWG 140 24 ACT 134 am Assy GWS 222 A A INDICATOR 008 19 A 14 SPEAKER A NDICA EN Qi TA7318P A BRIGHTNESS i Pa gie SPEAKER M 1 Olen H rt r cias ca i ASX 137 Ol a HN wx 8 1 4 7 50 220 6 RSS 1 E r BAL 300n 9 ss i Sma uod Wo 1 10 BRIGHT DIMMER T3 BASS Hee SS 750 T o Y 1 GND s9 AM mi ho 19 S7 Qa 251906 H I 12 1 BLU Q s a 2 EEE e C34 c35 NR RATIO ON OFF YEL E 150p 150p er amp 5G SWITCH Ass y 8 i ORGO GWS 220 P R36 8 2k _ IWI x S8 TONE R133 6 LOUDNESS 1 c303 ms R49 750p ASK 152 3990 R303 47k 47k ASG 230 150p 8303 1 I 1 734 L16 j I D amp 2 MZ 061 0 29 512 1 T D3 151555 200 047 5602 fea Vz3 123 eama hea fied 2 E ON OFF f 2 3 4 5 6 7 8 9 10 4 TT t s R62 i 011
2. TE CHATEOT07 0 Fig 4 13 Signal Indicator Circuit abruptly decay and Q5 will conduct owing to the residual component of B As a result C4 will rapidly discharge Q6 will cease to conduct where upon the relay will become de energized and restore muting DC Voltage Detector The output circuit is connected to the Q3 emit ter and Q4 base via a low pass filter R5 C2 Any DC voltages appearing the output circuit of the power amplifier it will be applied to the Q3 emitter and Q4 base If the voltage is positive Q4 turns on C4 will rapidly discharge If the voltage is negative Q3 turns on C4 will rapidly discharge As consequence Q6 will turn off and the relay will become de energized thus causing the output circuit to open Fig 4 14 Protection Circuit 14 Overload Detection The overload detector circuit incorporates the load RL in one side of a Wheatstone bridge see Fig 4 15 The base and emitter of a sensing transistor Q2 are connected to the opposite comers of the bridge so if RL decreases Q2 will become forward biased If RL falls below a pre scribed value Q2 will turn on C4 will rapidly discharge As consequence Q6 will tum off and the relay will become de energized thus causing the output circuit to open Fig 4 15 Overload Detector 5 DISASSEMBLY Wooden Cover Remove the two screws on each
3. PLA 8 BV 50mA PL6 AUX INDICATOR Ass y AWN 008 Erne uae SWITCH Assy GWS 221 LN uk in painin cina cost LXI AM Jf STEREO 29 e The JP14 and JP15 jumper wires in the equalizer assembly AWM 226 constitute the program circuits em BY 300mA SWITCH Ass y GWS 223 19mA POWER SUPPLY Assy AWR 210 aa ployed to match the counter IC PD5009 located in the indicator assembly with the FM IF offset value These jumpe
4. 42 34 35 8iV50mA Am ARS PL12 mp Signal route M d Q14 16 21 sig 5 A EL 069 Xx noce God 2 Adjusting point Y M CM AF 065 2SC2575 The mark found on some component parts indicates the im STEREO Q22 23 28 35 5 Wu portance of the safety factor of the part Therefore when replacing p 2SA1100 L B08 oF be sure to use parts of identical designation pu sve 01 2 2SK34 aio Q5 2SA912 2 H Bis K Q3 25 25C2575 Q6 25B682 bt the na AEL 069 0101106 due to improvements in design E MZ 061 0109410 STV2H SWITCHES 51 TAPE MONITOR 1 SOURCE 2 S2 DUPLICATE ON OFF 114 412 117 118 S3 ADAPTOR ON ger 36 38 39 40 41 VRM2 OFF SET EN er 16 4 MODE STEREO MONO VOLTAGE ADJ v v AD aus 5 MUTING 20dB ON OFF FUNCTION D129 130 132 133 56 LOUDNESS ON OFF 1567226 152471 67 1 FUNCTION ON OFF 0131 MZ 150 57 2 FUNCTION AM ON QFF 57 5 FUNCTION AUX ON OFF 57 4 FUNCTION PHONO2 ON OFF 57 5 FUNCTION PHONO 1 ON OFF Q8 254905 i FUSE Ass y 2 2 9 F G HiJ RECTIFIER Assy 9911 25015 awn 226 L 9 TURNOVER Hz 20
5. E E sc P n Mo r P F wa CPREOUTZ MAN ING 28 aco Masten Eine een d tea IA teasing ta ER ENT Es RUBRO d Jie ATEM E NUN SIR MEE asas raisa SAE GAR MEER F ee ee PHONON PLA KPHONO2 PL8 FM banner PL7 AM isn STEREO n MR dl
6. NE Dt tww 20000004 t E Fig 4 7 Power Indicator Circuit 11 BRIGHTNESS SELECTION DIGIT DRIVER SEGMENT DRIVER REF osc 17512 ose DIVIDER 1 1 wen eel ezine DECODER pe POINT SSION rei s wucriecexer counter e CONTROL CIRCUIT arcu Coad LATCH care BE COUNTER FROM PRESCALAR COUNTER PRESETABLE 5 DIGIT DECIMAL COUNTER I jeri 22 x 16 ROM GND Fig 4 10 Block Diagram of Counter IC PD5009 An outline of the composition of PD5009 is given in block diagram form in Fig 4 10 With the FL tube g segments anode for each digit con nected in parallel the D1 D5 time division pulse signals see Fig 4 11 applied to each grid inde pendent grid for each digit result in the digits being lit up in succession from the left hand side Each digit is lit up for Ims during each 5ms inter val Pin no 7 of PD5009 is the brightness selector terminal The time division pulse width is set to 800us for H level input signals and to 200us for L level signals thereby varying the degree of FL tube brightness by varying the segment lighting period
7. The mark found on some component parts indicates the importance of the safety factor of the part Therefore when replacing be sure to use parts of identical designation Key No Part No Description 1 VBZ30PO60FMC 2 Holder 3 VMH30P120F Mc 4 Socket stopper 5 28C2526 6 2SA1076 7 AEC 488 Insulator wafer 8 AKH 010 Transistor socket 9 Heat sink 10 PA holder A 11 BBT30POSOFZK 12 PA holder B 13 AWH 097 Power amplifier assembly 14 VBZ30POSOFMC 18 STV2H 16 WA33F100M100 45 13 PACKING Parts List Key No Part No Description ARB 354 ADH 002 AHA 247 AHC 042 AHD 756 KERN e AHA 251 46 Operating instructions T type FM antenna Side pad Inside packing Packing case Rear pad PIONEER 1 1 No SI A84016 INFORMATION Date November 1983 MopEL SX 3900 KU 5 6 SUBJECT Addition of resistors into Power Amp Assembly REASON For easier Idle current adjustment R200 R201 Added 1000 RD1 4PM101JNL Service MANUAL Pace SX 3900 series ART 457 APPLICABLE SERIAL No SX 3900 KU 3603601 SX 3900 S G 2904551 POST OFFICE BOX 1760 LONG BEACH CALIFORNIA 90801 J W C PHONE 213 420 5700 FAX 2131420 5902 PIONEER ELECTRONICS USA INC TECHNICIAL INFORMATION CENTER ADDITIONAL Service 7 X 3900 The basic performance of the S G type is the same as the KU type This additional service
8. 400Hz 75kHz deviation and tune the SX 3900 to this position fine adjust the tuning knob to ensure a DC OV reading between no 8 and no 7 terminals 12 Then rotate the B core of T2 to reduce distor tion in the demodulator output TAPE REC terminal to minimum 13 Repeat steps 9 to 12 above until both specifica tions are satisfactorily met 14 Set the FM SG output to 98MHz and 60dB and tune the SX 3900 to this position 15 Adjust VR2 so that the SIGNAL indicator 5 point display reads 5 20 16 Turn the MUTING OFF switch to the ON position and set the FM SG output level to 20dB 17 Adjust VR1 to bring the input level to the starting point of the muting operation Multiplex Decoder Connect the MPX SG FM multiplex generator to the FM SG external modulator terminal e Set the FM MUTING OFF switch to the OFF position 18 Set the FM SG output to 98MHz and 60dB unmodulated and tune the SX 3900 to this position fine adjust the tuning knob to ensure a DC OV reading between no 8 and no 7 ter minals 19 Adjust VR5 to obtain a 76kHz signal at termi nal no 6 20 Set the FM SG output level to 60dB and the modulation mode to external Then with the MPX SG set Main off and pilot signal to 7 5kHz deviation 21 Adjust VR4 to reduce leakage of the 19kHz pilot signal in both channels to a minimum at TAPE REC terminals 22 Set the FM SG output level to 80dB the MPX SG Main to
9. 40dB Aan Ferrite loopstick antenna Audio Section Output Level Impedance FM 100 Mod 650mV 24 kilohms AM 30 Mod 200mV 2 4 kilohms Semiconductors e vac 15 FETs 5 6 Transistors 89 Diodes 62 Miscellaneous Power Requirements AC 120V 60Hz Power Consumption 350W UL Dimensions 526 W x 176 H x 452 D mm 20 11 16 W x6 15 16 H 17 14 16 D in Weight without package 20kg 4416 202 Furnished Parts Operating instructions 21 T type antenna Measured pursuant to the Federal Trade Commission s Trade Regulation rule on Power Output Claims for Amplifiers NOTE Specifications and the design subject to possible modifications without notice due to improvements 2 FRONT PANEL FACILITIES D POWER SWITCH Set this switch to ON to supply power to the receiver There will be a short delay when it is set to ON because the muting circuit has been actuated to suppress the unpleasant noise that is sometimes generated when the power is switched on and off BASS TURNOVER SWITCH Use this switch to change over the frequency in which the sound adjustment with the bass control is starting to take effect Select 200Hz or 400Hz in accordance with the characteristics of your listening room and of your speakers and with your general prefere
10. 2 as si i On Q all Eig P g gt 5 In H LLL Li Di2 2 061 TA D3 151555 047 Peer 9 8 i S9 TURNOVER H J 9 4 n I se Tone RS ASK 152 390 I AO 58 4 2 24 1 53 2 PLAY2 a H 4 4 I 011 PA4006 A uc 28 27 26 25 24 23 22 21 20 1 H 512 A Muy 3 ADAPTOR Op ASG 229 e Is ASX 130 eol wit 2 3 4 5 6 7 8 H 280461 Q3 HAI2010 I 1 R147 4 76 46 15 14 13 R n 9 O Ra ADAPTOR IN SS 2 L L 23 tu Ari d ADAPTOR OUT 8 2 3 BEN 32 SIE VRS VCO ADJ Q RIS 17 a 241 bi gt Fo 50 su ern j a TAA cce C alg C 0 o0 AES L CH 25 C52 C72 oft R67 3 12 M 10 24 23 22 21 20 19 18 17 22 o H ion TTY PLAY2 j 1 50 100k R C2 P m 2 47 50 i Rito m m O O i GwS 221 HE Ts 6110 2 C945A or 2SC2575 ASE 55k am GWK 146 680 ch z N PLAY 1 gt 16 aa EA 5p PLAY 1 REC 1 ASX 133 R CH C75 39p cso 6 01 _ aLi Q uw maksa 9 5 ma evi I 2 3 2k 1 2 22 REC2 POWER AMP Assy AWH O97 jVR6 BALANCE p 55 MUTING MEG
11. 4006 RSs Ree H O Zar 28 27 26 25 24 23 22 21 20 1 E 3 4 5 6 7 8 12 R lt CRNCELER ADJ Q3 HA12010 16 15 14 15 2 11 9 0 947 m m et Gas es 4 F 24 C T B 23 o m ER 22 L CH VR MUTING LEVEL B 7 16 15 PLAY2 C92 i mote A Assy 2 2 HONE T FTT e DES EN t GwS 221 ACK Ass y REC 06 10 THOTT GWK 146 VR2 SIONAL LEVEL 59 a T PLAY 1 7 92 049 i HOLT 1 PMDE EMPHASIS SWITCH Ass y 2 fe gt 7 S097 C4 1500 PLAY 1 St 2 Sloe i HH Y MONITOR l REC 1 ASX 133 PLAY2 3 R CH 4 REC 1 POWER AMP Assy AWH 097 Ece es ae IVR6 BALANCE 47k ASK 152 012 HA1197 ADAPTOR OUT VR VOLUME ma Rosa STERN 1 RESISTORS ADAPTOR IN tok Indicated in 0 WW 5 tolerance unless otherwise noted k R148 4 7k L RS IUE M MQ F 21 G 2 10 tolerance CURRENT 1 ADJ Qin4 25C2526 H3 A amp amp ACP 019 Q5 8 2SA1076 2 CAPACITORS m UE L TRS Indicated i
12. HIGH 8kHz 6dB oct Loudness Contour Volume control set at 40dB position Cu tele eq uA ETES 6dB 100Hz 3dB 10 000Hz Hum and Noise IHF short circuited A network PHONG eorr edicto usu 86dB AUX TAPE PLAY 1 2 ADAPTOR IN 105dB Attenuator 20dB FM Tuner Section Usable Sensitivity IHF 9 8dBf 1 7uV 50dB Quieting Sensitivity Cu Cues sap 14 2dBf 2 8uV STEREO e S 36dBf 34 7uV Signal to Noise Ratio MONO 83dB at 65dBf 78dB at 80dBf STEREO Distortion at 65dBf MONO 100Hz 0 1 0 07 6kHz 0 1 STEREO 100Hz 0 2 1kHz 0 15 6kHz sy 0 2 Capture Ratio hr 1 0dB Alternate Channel Selectivity AOOKH DIPEPE dan s Sa 80dB Stereo Separation 1kHz 30Hz to 15kHz Frequency Response vis bate siege 20Hz to 15kHz 02 dB Spurious Response Ratio 100dB Image Response Ratio 90dB IF Response Ratio 100dB AM Suppression Ratio 60dB Subcarrier Product Ratio 64dB SCA Rejection Ratio 64dB Muting Threshold 19 2dBf 5uV Antenna Input 2 poiss 300 ohms balanced 75 ohms unbalanced SX 3900 AM Tuner Section Sensitivity IHF Ferrite antenna 3004 V m IHF Ext antenna 15uV Selectivity Pat 30dB Signal to Noise Ratio 50dB Image Response Ratio 40dB IF Response Ratio
13. SIGNAL Indicator Circuit The SX 3900 SIGNAL indicator consists of an FL tube 5 point indicator display The signal meter drive signal obtained from the FM IF system IC PA3007 A and AM tuner IC HA1197 is first amplified and then applied to the indicator drive IC HA12010 This IC contains 12 pairs of voltage comparators similar to those employed in the power indicator circuit 5 of these pairs being used to drive the SIGNAL indicator Fig 4 13 4 5 PROTECTION CIRCUIT The purpose of this circuit is to protect both the speakers and the power amplifiers The relay in the output circuit is automatically opened in any of the following cases 1 During the transient operations when the power supply is turned on and off 2 Upon detection of a DC voltage in the output circuit caused by component failure or acci dent 3 Upon detection of an overload caused by a short circuit in the load Muting Operation when Power Supply is Turned On and Off With reference to Fig 4 14 when the power supply is turned on Q5 turns off due to B The time constant of the B circuit is very small If there is no input DC on Q3 and Q4 they will be off and the timing capacitor C4 charges up through R8 and R7 and thus Q6 turns on When Q6 conducts the relay operates and the output muting on the power amplifier will be removed When the power supply is turned off B will T3 FL TUBE SIGNAL appt
14. C61 C62 C72 C79 C98 C97 C33 C43 C56 C69 C85 C73 C80 C30 C76 C77 C36 C83 C84 12 C54 C51 C85 C4 C78 When ordering resistors convert the resistance value into code form and RESISTORS then rewrite the part no as before Part No Symbol amp Description C92 048 VRi VR3 Semi fixed 47k B C92 049 2 Semi fixed 10 056 Semi fixed 22k B ACP 055 VR5 Semi fixed 6 8k B ACT 133 VR6 Variable BALANCE ACW 304 Variable VOLUME 36 RDY PM 000 J RD PMF 000 J RNXPO DODO F RN SO 0000 F SEMICONDUCTORS R1 R11 R13 R15 R22 R24 R29 R31 R45 R47 R49 R52 R63 R65 R67 R70 R123 R125 R128 R152 R12 R46 R126 R50 R51 R30 Part No Symbol amp Description 3SK73 Q1 25K34 02 2SK168 03 015 28C1906 28C535 A o5 HA1201 Q6 07 09 NJM4558DV as PA3007 A Q10 PA4006 A Qn HA1197 012 2561919 013 2502575 Q14 016 021 024 016 28C945A 28A1100 Q22 023 028 035 2SA733A HA12010 027 MZ 061 D1 D2 W2 061 151555 03 05 017 152473 1569 03 D18 COILS AND FILTERS Part No Symbol amp Description T24 028 L4 L7 19 113 L15 L16 Choke coil ATC 097 L2 FM antenna coil ATC 099 L5 L6 FM RF coil ATC 072 L8 FM osc coil ATE 008 FMIFT ATE 045 T2 FM DET ATB 063 T3 AM osc coil ATB 069 AM IF coil ATF 104 1 FM ceramic filter e The FM ceramic filters ATF 104 symbol nos Fl in the tuner assembly
15. Distortion ratings and S N ratio have been further improved by incorporating a chopper type MPX decoder The chopper type switching circuit see Fig 4 2 operates by switching the signal either to ground or to the through circuit thereby eliminating the generation of unwanted noise or distortion Furthermore since the PA4006 A fea tures DC direct coupled switching with the detec tor there is no deterioration in separation at the low frequency end Besides the decoder and muting circuits the PA4006 A also incorporates the pilot signal cancel ler stereo auto selector VCO killer circuit MUT amplifier and MUT control circuit Composite uy signal Ay Output Input Switching signal o Fig 4 2 Chopper Type Switching Circuit 4 2 AM TUNER SECTION The AM tuner section consists of a 2 ganged tuning capacitor plus an IC HA1197 which con tains a l stage RF amplifier converter 2 stage IF amplifier detector and AGC circuit The AM STEREO OUT terminal on the rear panel is for connecting to an AM stereo broadcast decoder adaptor The signal appearing at this ter minal is the converter output passed via a buffer emitter follower stage SX 3900 4 3 AUDIO SECTION Phono Equalizer Amplifier Fig 4 3 shows the basic configuration of the circuit An S N ratio of 86dB at 2 5mV input IHF A has been achieved by using a ultra low noise PNP transistor 2SA978 at the first stage and reducing the signal source resi
16. Service c Manual FM Quartz Locked STEREO RECEIVER SX 3900 WPIONEER MODEL SX 3900 COMES IN TWO VERSIONS DISTINGUISHED AS FOLLOWS Type Voltage Remarks KU 120V only U S A model 5 6 110V 120V 220 and 240V Switchable U S Military model This service manual is applicable to the KU type When repairing the S G type please see the additional service manual see pages 47 56 CONTENTS 1 SPECIFICATIONS 2 2 FRONT PANEL 4 BLOCK DIAGRAM sedesa reies dips teas 7 4 CIRCUIT DESCRIPTIONS 4 1 FM Tuner Section 8 4 2 AM Tuner Section 9 4 3 Audio Section 9 44 Display Circuits 11 4 5 Protection Circuit 13 4 6 Surge Current Suppressor 15 DISASSEMBLY 15 5 6 PARTS LOCATION 7 DIAL CORD STRINGING 8 ADJUSTMENTS 8 1 Audio Section 2 2 0 2 eee ee eee 19 8 2 Tuner Section 20 9 SCHEMATIC DIAGRAM via 24 10 P C BOARDS CONNECTION DIAGRAM 29 TIS PARTS LIST 35 12 EXPLODED VIEW 13 PACKING ADDITIONAL SERVICE MANUAL FOR 5 6 TYPE 47 1 SPECIFICATIONS Power Amplifier Section Continuous Power Output of 120 watts per chan nel min at 8ohms from 20Hertz to 20 000 Hertz with no more than 0 005 total harmo nic distortion Total Harmonic Distortion 20 Hertz to 20 000 Hertz 8 ohms continuous rated power output No more than 0 005
17. 60 watts per channel power DUtDUt uae Dee tage RE No more than 0 005 Intermodulation Distortion 50 Hertz 7 000 Hertz 4 1 continuous rated power output No more than 0 005 60 watts per channel power Qutp t iiec No more than 0 005 Frequency Response 5 Hertz to 200 000 Hertz n dB Input Sensitivity Impedance POWER AMP IN dris NL Mee ERE oido 1V 50 kilohms Output Speaker A B A B Damping Factor 20 Hertz to 20 000 Hertz 8 ohms ibus hab are 60 Hum and Noise IHF short circuited A network 115dB Preamplifier Section Input Sensitivity Impedance PHONO 172 2 5mV 50 kilohms AUX TAPE PLAY 1 2 ADAPTOR IN 150mV 50 kilohms Phono Overload Level T H D 0 005 1 000 Hertz PHONO4 2 hee tu 300mv Output Level Impedance TAPE REC 1 2 ADAPTOR OUT PREAMP OUT R 50 kilohms 1V 1 kilohms Volume max Total Harmonic Distortion 20 Hertz to 20 000 Hertz PHONO 1 2 RECOUT No than 0 005 10 output AUX TAPE PLAY 1 2 ADAPTOR IN No more than 0 005 10V output Frequency Response PHONO RIAA Equalization 20 Hertz to 20 000 Hertz 0 2dB AUX TAPE PLAY 1 2 ADAPTOR OUT 7 Hertz to 80 000 Hertz 0 dB Tone Control BASS scie er 4dB 7dB 100Hz Turnover Frequency 200Hz 400Hz TREBLE us oot prassi 9dB 7dB 10kHz Turnover Frequency 2kHz 4kHz Filter LOW tuus 15Hz 6dB oct
18. Description 25K34 01 02 2SD313P 25 1885 Q4 2SA912 95 2SB682 258507 28C1915 07 25 905 os 250313 09 011 28C2575 Q10 181555 01 011 182076 1082 D2 D5 07 010 KZL 140 D6 MZ 110 014 002 110 MZ 130 D13 Wz 130 MZ 177 D12 WZ 177 OTHERS Part No Symbol amp Description ATT 678 Ti Heater transformer PBZ30POGOFMC VBZ30PO60FMC Parts List of Detector Assembly GWX 463 CAPACITORS Part No Symbol amp Description CCDSL 101J 50 CCDWK 150K 50 CKDYB 471K 50 CKDYF 103Z 50 C201 C202 C204 C206 39 Note When ordering resistors convert the Parts List of Rectifier Assembly AWR 211 resistance value into code form and RESISTORS then rewrite the part no as before CAPACITORS Part No Symbol amp Description Part No Symbol amp Description RD 4PM ODO J R201 R208 ACG 004 c1 c2 Ceramic 0 01 150V ACH 210 Electrolytic 15000 71V SEMICONDUCTORS ACG 017 cs Ceramic 0 01 125V Part No Symbol amp Description Note When ordering resistors conuert the resistance value into code form and 2SC461 B Q201 RESISTORS then rewrite the part no as before 24K261 0201 D202 Part No Symbol amp Description OTHERS A ACN 019 R1 Wire wound 3 3 20W ACN 029 R2 Carbon composition Part No Symbol amp Description 2 2M AW ATE 050 T201 FM DET EMIC CT ASS 012 1 Crystal resonator E ONDUCTORS Part No Symbol amp Description e The crystal resonator ASS 012 symbol n
19. Note that since the power indicator FL tube is driven by static drive the degree of bright ness may be varied by changing the grid voltage The 5 12MHz crystal oscillator generates the basic signal used in the preparation of the time division pulse signal and the counter gate circuit control signal mtd DS TEE aT 1009s 1005s PATER TNT glee HI he DA CC e L5 t6 BC L DIM 200ys SL ft on 1 dba Sms Fig 4 11 Digit Signal AB Table 1 MODE 51 S2 S3 S4 Intermediate frequency H L H H 10 67MHz FM HLHL 10 70MHz H L L H 10 73MHz AM L oH HEL 450kHz Terminals S1 S4 pin nos 3 6 are used in designating reception mode The 2 reception modes employed in the SX 3900 see Table 1 are designated by varying the combination of input levels H and L The 3 different IFs during FM mode are required in coping with IF offset in the IF ceramic filter stage S3 and S4 being preset during FM mode according to the ceramic filter characteristics Although the SX 3900 FM stage quartz lock system is capable of locking any frequency within the FM band the 10kHz digit digit in the second decimal place in the FM frequency display will appear only as 5 or 0 The frequency display FL tube also incorporates the TUNING and SIGNAL indicators And al though the segments anode for these indicators are static driven by the corresponding drive cir cuits the grid is driven accord
20. TAPE MONITOR 1 SOURCE 2 5 0132 2 DUPLICATE ON OFF 25 S3 ADAPTOR ON OFF gE sbL 4d6d464 2 D11 2 117 118 S4 MODE STEREO MONO PHONO2 7 VRI 2 OFF SET 40E2 55 MUTING 20dB ON OFF Ras 6 38 39 40 41 51 50 49 43 44 45 46 47 48 VOLTAGE ADJ RIO RIS D1M3 116 S6 LOUDNESS ON OFE G4 Ec na E 57 1 FUNCTION FM ON OFF 5 456 228 s 2 s e S247 57 2 FUNCTION AM ON OFF ci 2 T 57 3 FUNCTION AUX ON OFF 47 FM AM D131 MZ 150 zZ 2 ra R mn 57 4 FUNCTION PHONO2 ON OFF g S7 5 FUNCTION PHONO 1 ON OFF S8 TONE QN OFF D S9 TURNOVER Hz 200 400 4 Q9 14 2SD313 gt A 510 TURNOVER Hz PL9 PLIO L SP A SP 8 0101 102 25 1775 2k 4k Sii 1 2 FILTER I5Hz ON OFF Q103 104 2SA979 ON Q123 124 2SCI914A 518 UNE VOLTAGE SELECTOR 220V 240V 120V 110v Q1 2 2SA978 Fut AEK T 0 200mA I 511 34 FILTER 8kHz oFF I 151555 v v S BV Q105 106 25 2291 SI2 1 FM MUTING ON OFF D2A5 10E2 PLIO 8V50mA 107 108 FM DE EMPHASISQ Bus ON 06 KZL 140 gt 3 261 047 0111 112 254750 812 2 us ON QEE 07 10 10E2 18 300 4 er 012 MZ 177 mal 7779 09 110 25 1915 514 SPEAKERS A ON OFF DIS MZ 130 AEL 029 9113 14 25 00 515 SPEAKERS B ON OFF 014 MZ 110 aa SWITCH Ass y Q119 120 56 1 SPEAKERS
21. 012 HA1197 DAPTOR OUT IVR7 VOLUME ACW 304 w 15 2 1 VRT 4 1 2 RE Won gt E 10k r 5 22 23 24 2526 27 28 29 30 54 5352 Ee eee A 8 ADAPTOR IN 1 RESISTORS Indicated in Q WW 5 tolerance unless otherwise noted k VR3 4 IOLE T mara CURRENT S ADJ Qi 4 2502526 M Mo 1 G 296 K T0 tolerance 9087 en 3 Q5 8 2SA1076 0 54mA 2 CAPACITORS Indicated in capacity F voltage V unless otherwise noted p pF Indication without voltage is 50V except electrolytic capacitor R115 u 22 E EC SEPIUS ee 100k OH Z Sy A I L v vi AAV O07 D103 MO 149 ar an 1S 100 ior E 2 2 DHS 3 m K RH R92 VV 82k C36 0 047 RI38 cos ik 3 3 750 us Are Em 013 2SCI919 Q8 NJM45580V 2 2 Aes 6 0 se UIT AN PLA PHONON P45 PLBC FM 3 VOLTAGE CURRENT Signal voltage at 120 W 120 W 8 output IkHz XN DC voltage V at no input signal A epe a a0 05 dedi ER Value in is DC voltage at rated power VR5 6 IDLE L input signal 27k 12 8 CURRENT2 AD F lt mA current at no input signal ACP 302 DU EEE 4 OTHERS
22. 1kHz L R to 67 5kHz deviation and pilot signal to 7 5kHz deviation 23 Rotate the T1 core around by up to 90 in either direction to reduce the demodulator output TAPE REC terminals distortion to a minimum 24 Then set the FM SG output level to 60dB the MPX SG Main to 1kHz L or R to 33 75kHz deviation and pilot signal to 7 5kHz devia tion 25 Adjust VR4 to reduce crosstalk between L and R channels to a minimum Crystal Detector Set the FM MUTING OFF switch to the OFF position 26 Set the FM SG output to 98MHz and 60dB unmodulated and tune the SX 3900 to this position fine adjust the tuning knob to ensure a DC OV reading between no 8 and no 7 ter minals of the tuner assembly 27 Rotate the B core of T201 to obtain a reading of DC OV within 30mV between terminal no 9 and ground 28 Set the FM SG modulation to 400Hz 75kHz deviation 29 Rotate the A core of T201 to minimize AC signal level between no 9 and ground 9 N terminal SX 3900 Fig 8 2 Adjustment of the tuning coils AC voltmeter Distortion meter To TAPE REC q E m 16 5 ani MN VRI ER SGN VR2 TC4 TC2 7201 fele Ag Tuner assembly Detector assembly 2
23. 222 Equalizer assembly AWM 226 Power amplifier assembly AWH 097 Detector assembly GWX 463 Tuner assembly GWE 132 Indicator assembly AWV 008 Lamp socket AKK 005 Lamp wedge type AEL 029 Power transformer ATT 675 Tone amplifier assembly GWG 140 17 7 DIAL CORD STRINGING 1 Remove the wooden cover and the front panel 2 Turn the tuning capacitor shaft fully clockwise 3 Fix the tuning drum to the tuning capacitor shaft so that the set screw is uppermost 4 Tie one end of the dial cord to the spring 5 Pass the cord through the cutout section in the tuning drum Wind it 1 2 turn around the tuning drum and then take it over pulleys A B C D and E in that sequence 6 Wind the cord around the tuning shaft 3 times Pass it over pully F wind it around the tuning drum 2 times and finally tie it to the spring so that it is tensioned Tuning drum Starting point 18 Tuning capacitor 7 Turn the tuning shaft and check that the cord moves smoothly Cut off any excess cord 8 Tum the tuning shaft counter clockwise as far as it will go 9 Align the dial pointer with the starting point of the dial scale third division from the left and then pass the cord over it 10 Check that the dial pointer is in line with the starting point of the dial scale 11 Finally apply the locking paint to the knot of the cord and the dial pointer connection 12 If the tension of the cord is w
24. 683G 50 CKDYF 1032 50 CKDYF 473Z 50 Note RESISTORS Part No C19 C20 C9 C10 25 28 C23 C24 When ordering resistors convert the resistance value into code form and then rewrite the part no as before Symbol amp Description RDYPM ODO J RNXPQ OOOO RS2P 000 J SEMICONDUCTORS R1 R12 R15 R16 R21 R46 R13 R14 R17 R20 R47 Part No Symbol amp Description 25 978 01 02 2SC1775A 04 28C1885 05 06 2SA912 07 08 181555 D1 D2 152076 OTHERS Part No Symbol amp Description ASG 228 51 5 gang push switch AKB 064 Terminal INPUT AKB 063 Terminal PRE AMP OUT POWER AMP IN Parts List of Power Supply Assembly AWR 210 CAPACITORS Part No Symbol amp Description ACG 004 C2 C14 C18 C19 Ceramic 0 01 150V CCDSL 101K 50 CEA 100M 50L CEA 2R2M 50L CEA 470M 251 CEA 101M 25L CEA 470M 50L CEA 470M 63L CEA 471M 6L CEA 221M 16L 7 C8 C5 C24 1 c9 C16 C12 C13 C10 C11 C23 C17 CEA 331M 25L CEA 100M 63L CEA 471M 16L CEA 102M 35L CEA 221M 80L Note C22 c6 C20 C21 C15 C3 C4 When ordering resistors convert the resistance value into code form and RESISTORS then rewrite the part no as before Part No Symbol amp Description RSIP DOO J R3 R16 R17 RD PS 000 J R11 R12 RDYPSF DOD J R23 R24 RDXPMF 000 J R4 R7 RDY PM DOC J SEMICONDUCTORS R1 R2 R8 R10 R13 R15 R18 R22 R25 R26 R27 Part No Symbol amp
25. 9 NC AVRS Fi vrai g L 0 6 G VRB To FM ANTENNA 3002 terminals IN EXT MOD U Fig 8 3 FM tuner adjustment Fr equency Display Circuit The counter IC PD5009 has been designed to match FM ceramic filter IF offset caused by displacement of the central frequency by combination of the inputs of H or L level applied to pin nos 3 amp 4 The matching IF offset in the SX 3900 is determined according to the combinations of connections and disconnections between the JP14 and JP15 jumper wires in the equalizer assembly AWM 226 Check that the combinations shown in the table below have been followed for the corresponding grades of FM ceramic filters F1 F3 5 ranks color coded e If the SX 3900 frequency display reads 97 95MHz or 98 05MHz when a 98 00MHz signal is applied to the receiver adjust TC1 so that the display reads 98 00MHz correctly If an accurate 98 00MHz input signal source is not available tune the receiver to the nearest known broadcasting station in the 98MHz re gion and check that the station s frequency is correctly displayed adjusting TC1 if necessary FM ceramic filters PD5009 AWM 226 Fi F3 Pin no 3 Pin no 4 JP14 JP15 Red L H Cut Connect Blue H H Cut Cut Gray H L Connect Cut Orange H L Connect Cut Brown H H
26. Adjust TC6 to obtain maximum demodulated output at TAPE REC terminal Repeat steps 5 to 8 above Set the SX 3900 dial pointer to 600kHz and the AM SG output frequency to 600kHz Slide the bar antenna coil along the core to find the position which gives maximum demo dulated output at TAPE REC terminal Tune to 1400kHz and set the AM SG output frequency to 1400kHz Adjust TC5 to obtain maximum demodulated output at TAPE REC terminal Repeat steps 10 to 13 as above frequency to 600kHz Adjust T4 and F7 to obtain maximum demo dulated output at TAPE REC terminal Oscilloscope To TAPE REC terminal ID E H 9 To AM ANTENNA 1k22 resistor terminal Fig 8 5 AM tuner adjustment 9 SCHEMATIC DIAGRAM External Appearance of Transistors and ICs 2847265 Dot Lot No Type No 2SA733A 2SC945A 2SC1775A 254979 Type No IN Lot No hee e B2 28SA985A 2SA978 25 1919 2541100 25 2575 Lot No Type No hee x 2SA750 28C1400 Lot No Type No hre 2SA904A 28C1914A Suffix Lot No Type No hee 24 2SA905 2SC 915 Lot No Type No hee 2SA912 2SC1885 tot No Type No hee 258682 2SA1076 2SC2526 Type No Lot No hee 25 461 2SC535 Type No I Lot No PA3007 A Lot No Type No toss S
27. CAPACITORS Part No Symbol amp Description CCDSL 101K 50 CCDSL 470K 50 CCDSL 471K 50 COMA 332J 50 123J 50 COMA 124J 50 CEANL R33M 50 CEANL 010M 50 CEANL 100M 50 CEANL OR1M 50 CEA 470M 25L CEA 470M 501 CEA 101M 10L CEANL 4R7M 50 Note RESISTORS Part No C5 C6 C11 C12 C3 C4 C13 C14 C31 C32 C23 C24 C27 C28 C25 C26 C29 C30 C15 C16 C19 C20 C17 C18 C21 C22 C33 C34 C35 C36 C37 C38 C9 C10 C39 C42 C7 C8 C1 C2 When ordering resistors convert the resistance value into code form and then rewrite the part no as before Symbol amp Description ACT 134 RD PM GOOG J VR1 VR2 Variable BASS TREBLE R3 R40 R43 R44 Parts List of Power Amplifier Assembly AWH 097 CAPACITORS Part No Symbol amp Description CEANL 4R7M 50 CCDSL 221K 50 CCDSL 470K 50 CCDSL 470J 50 CCDSL 390K 50 332K 250 A CCDSL 101K 500 CEANP R22M 50 ACG 009 CKDYB 472K 50 823K 50 CEA 471M 6L CEA 101M 251 Note C101 C102 C103 C104 C105 C108 C109 C110 111 C112 113 C114 C121 C122 C127 C128 C129 C130 C131 C134 Ceramic C135 C136 0 047 150V C137 C138 C139 C140 When ordering resistors convert the resistance value into code form and RESISTORS then rewrite the part no as before Part No Symbol amp Description ACP 035 VR1 VR2 Semi fixed 330k B ACP 019 VR3 VR4 Semi fixed 100 B ACP 302 VRS VR6
28. Cut Cut H 5 5V L 0V h Cat JP14 TCi u X a Indicator assembly JC JP15 Equalizer assembly il 22 Fig 8 4 Adjustment of frequency display AM Tuner T Connect the AM SG AM signal generator to the AM ANTENNA terminal via 1kQ resistor Switch the FUNCTION selector to the AM posi tion Set the SX 3900 dial pointer to 600kHz and the AM SG output to 600kHz 100dB modula tion 400Hz 30 Adjust the core of T3 to maximum demodu lated output at TAPE REC terminal Then set to 1400kHz and set the AM SG out put frequency to 1400kHz also This time adjust TC6 to obtain maximum demodulated output at TAPE REC terminal Set the SX 3900 dial pointer to 600kHz and the AM SG output to 600kHz 30dB Adjust the core of T3 to maximum demodu lated output at TAPE REC terminal Then set to 1400kHz and set the AM SG out put frequency to 1400kHz rar E 1 9 NT Im F7 Te s e jf Tcs po ae oM 11 12 18 14 Tune to 600kHz and set the AM SG output 16 Bar antenna TEM SX 3900
29. SPA ON OFF 8 4 GWS 223 Q1i5 116 25A905 orate 294904A SIG ZSPEAKERS SPB ON OFF AWR 210 3 6 1 D102 S17 POWER ON OFF 1 03 4 2SC1775A FUS AEK 108 Q125 126 25 2575 QI3T 139 S19 FM DE EMPHASIS 50 75ys 05 6 25 1885 INE Ke 07 8 25A912 AC POWER CORD ADG 049 2561384 EL 1 ASRI38 Y Aare A s Q2 The underlined indicates the switch position 2 c 22 edm p 7 4 Ay 0133134 2562275 a aCe A piso 35 136 2SA985A a 200 01 55151 i I 100k 69 100k R45 C2 IQ 100 47504 fe AUX Do RCH owe WF QD iE Q 680 D Alf FAD GRN 6 R8 0 9 eid FU3 4 A 330 8 2k BRN AEK 106 02 S5151R 226 I ACKO CER N A e 516 SPEAKER 220 240v Q A ASX 135 MICRC 00000900 UNSWITCHED SWITCHED TOTAL 200 MAX 100W MAX PREOUT MAIN IN 53 PIONEER ELECTRONIC CORPORATION 4 1 Meguro 1 Chome Meguro ku Tokyo 153 Japan PIONEER ELECTRONICS CORPORATION 85 Oxford Drive Moonachie New Jersey 07074 U S A PIONEER ELECTRONIC EUROPE N V Luittiagen Haven 9 2030 Antwerp Belgium PIONEER ELECTRONICS AUSTRALIA PTY LTD 178 184 Boundary Road Braeside Victoria 3195 Australia ART 4870 Y O DEC 1978 Printed in Jepen
30. Semi fixed 100k B RDYPM 000 J R101 R108 R111 R112 R115 R116 R119 R120 R125 R126 R145 R146 R149 R152 R157 R158 R167 R170 R175 R182 R191 R194 R197 R199 aet Part Symbol amp Description RDXPMF ODD J R109 R110 R113 114 R117 R118 R123 R124 R127 R142 R147 R148 R153 R156 R159 R164 RT71 R174 51 000 J R121 R122 R143 R144 RDYPS R196 RN1H nan K R187 R188 RS2P O00 K R189 R190 R183 R186 Wire wound twin 0 47 5W x 2 SEMICONDUCTORS Part No Symbol amp Description 25 1775 0101 0102 or 28C1775A F 2SA979 F 0103 0104 or 2SA979 G hfe of Q101 and Q102 should have the E rank if Q103 and Q104 have the F rank hfe of Q101 and Q102 should have the F rank if 0103 and Q104 have the G rank 28C2291 Q105 0106 2SA750 Q107 0108 2547265 25 1915 0109 0110 28A750 0111 0112 0117 0118 25C1400 0113 0114 0119 0120 254905 0115 0116 28A904A 0121 0122 25 1914 0123 0124 2502575 0125 0126 0137 0139 28C2275A Q Q133 0134 or 2SC2275A P 2SA985A 0 Q135 0136 or 28A985A P hfe of 0133 0136 should have the same value 25C1384 0140 MZ 061 0101 0106 Wz 061 STV2H D109 0110 10E2 D111 D112 0117 D118 151555 0113 0116 152076 182471 D129 D130 0132 0133 MZ 150 D131 WZ 150 TH103 2 Th101 Th102 OTHERS Part No Symbol amp Description ASR 068 RL1 Relay PBZ30P060FMC 38 Parts List of Indic
31. dummy antenna e Switch the FUNCTION selector to the FM posi tion the FM MUTING OFF switch to the OFF position e L5 and L6 are coreless coils which may be adjusted by extending one turn of coil out to wards tuning capacitor see Fig 8 2 1 Set the SX 3900 dial pointer to a frequency in the 106MHz region so that there will be no input signal 2 Rotate the N core of T2 so that the voltage between no 8 and no 7 terminals on the tuner assembly is reduced to DC OV 3 Next tune the dial pointer to 106MHz and set the FM SG output to 106MHz 60 to 80dB modulation 400Hz 75kHz deviation 4 Adjust TC1 so that the voltage between no 8 and no 7 terminals is reduced to DC 0V and maximum reading of the SIGNAL indicator 5 Then tune the dial pointer to 90MHz and set the FM SG output frequency to 90MHz 6 Rotate the L8 core so that the voltage between no 8 and no 7 terminals is reduced to DC and maximum reading of the SIGNAL indica tor Repeat steps 3 to 6 above Reset the FM SG output level to 20 30dB and adjust TC2 TC3 TC4 and T1 at 106MHz and L2 L5 and L6 at 90MHz in the same man ner as described in steps 3 to 7 These adjust ments will ensure optimum sensitivity between the two extreme frequencies 9 Retune to a position with no input signal 10 Rotate the A core of T2 so that the voltage between no 8 and no 7 terminals is reduced to DC OV 11 Set the FM SG output to 98MHz and 60dB modulation
32. found on some component parts indicates the importance of the safely factor of the part Therefore when replacing be sure to use parts of identical designation Miscellaneous Parts Symbol amp Descri Tone amplifier assembly Switch assembly Power amplifier assembly Power supply assembly Speakers terminal assembly Switch assembly Headphones jack assembly Rectifier assembly Symbol amp Description c1 Ceramic capacitor 0 01 250V Ti Power transformer T2 Power transformer T3 Bar antenna assembly AC socket AC OUTLETS AC power cord Terminal AM STEREO OUT Transistor socket Lamp socket Jumper plug C2 C3 Parts List of Tuner Assembly GWE 132 Symbol amp Description Part No SEMICONDUCTORS GWG 140 Part No Symbol amp Description Gws 221 AWH 097 25 2526 01 04 AWR 210 2SA1076 05 08 GWs 222 Gws 223 FUSES GWK 146 Part No Symbol amp Description ort AEK 305 Fut 10A OTHERS AEK 102 Fu2 25A AEK 106 FU3 FU4 1A Part No ACG 001 A LAMPS A ATT 676 ATT 675 Part No Symbol amp Description TE 024 AEL 029 PLI PL3 Lamp wedge type Rabu AEL 069 PLA PL5 PL7 PL8 Lamp with wires AEL 095 PL6 Lamp with wires LIRE age AEL 047 PL9 PL10 Lamp with wires AKHTO AEL 075 PLI Lamp with wires AEL 065 PL12 Lamp with wires AKM 004 SWITCHES 224K 250 Part No Symbol amp Description ASK 507 517 Lever POWER ASX 128 Remote lever A
33. of base current from Q2 and prevents the generation of a DC voltage Because Q1 follows any temperature drift in Q2 temperature drift of the center point voltage is prevented The pre driver stage Q4 Q5 is a Darlington arrangement the load circuit of which employs a constant current source Q6 resulting a high volt age gain The power stage bias voltage is supplied by the high speed bias servocontrol circuit The high speed bias servocontrol circuit provides non switching operation in the power stage refer to High Speed Bias Servocontrol Circuit The power stage Q7 Q12 is a 2 stage Darling ton arrangement the final stage is parallel SEPP circuit Because there is no time constant in the NFB circuit in the low frequency region amplifi cation is possible down to DC DC inputs will be cut off however by the input coupling capacitor e High Speed Bias Servocontrol Circuit By operating the power stage only within the active region no possible cut off and with mini mum idle current the high speed bias servocontrol circuit prevents the generation of switching dis tortion and reduces heat loss This circuit is outlined in Fig 4 6 When there is no signal applied to the circuit Q1 and Q2 are almost cut off while Q3 and Q4 will be on The voltage across the collector and base of both of these transistors Q3 and Q4 at this time may be disregarded Consequently with the power stage bias circuit consisti
34. panel AEK 106 Fuse 1A 15 Dial pointer AEK 102 Fuse 2 5A 16 Shaft cover A A 61 AEK 305 Fuse 10A 17 Shaft cover B 62 AEL 069 Lamp with wires 18 Side frame L 63 AEL 095 Lamp with wires 19 Side frame R 64 AEL 047 Lamp with wires 20 Panel frame 65 AEL 075 Lamp with wires Center frame 66 327 Strain relief 22 Rear panel 67 Plate 23 Center channel 68 AKK 005 Lamp socket 24 Tuner holder 69 AKM 004 Jumper plug 25 Heat sink holder 70 Smoother 26 Transformer holder n Ground terminal 2 P 27 Scale board holder L 72 Lamp holder 28 Scale board holder R 78 Capacitor cover 29 EQ holder A 74 ABA 176 Special screw 30 EQ holder B 75 ABE 001 Internal toothed lock washer 31 Reinforced plate 76 ABN 050 Union nut 32 Ground plate 77 NKSOFUC 33 Acrylic board 78 WA92F140U100 34 Spacer A 79 WA35F100N080 35 Spacer 80 525 Nylon rivet 36 Rod 81 2 37 Pulley assembly 82 VBZ30POGO0FMC 38 Pulley assembly S 83 PMT3OPOGOFZK 39 Tuning drum assembly 84 MTZ30P100FZK 40 260 Tuning shaft assembly 85 VBZ3OPOBOFMC 41 Spring 86 250 42 Reinforced channel 87 PMZ30POGOFMC 43 Mounting clamp 88 VBZAOPOBOFMC A 44 07 Lever switch POWER 89 PMZ30P120FMC 45 ASX 128 Remote switch 90 AEL 065 Lamp with wires SX 39300 See page 45 Heat Sink NOTES Parts without part number cannot be supplied
35. the frequency to a higher frequency the voltage on pin no 4 will be higher than that on pin no 2 The Q20 collector voltage will thus be lowered and the Q19 collec tor voltage raised resulting in Q23 being turned on and the higher frequency right hand side detuning direction indicator also being turned on When on the other hand the broadcasting fre quency is approached from the low frequency side or when tuning away to a lower frequency the pin no 4 voltage will be lower resulting in Q22 being turned on to light up the lower frequency left hand side detuning direction indicator When either Q22 or Q23 is on the Q24 base voltage will be high resulting in Q24 being turned on and Q25 turned off which means that the center tuning indicator will not be lit up Once the broadcasting frequency has been tuned properly the voltages on pin nos 2 amp 4 will be equal Consequently Q22 and Q23 will both be turned off which means that neither of the detun ing direction indicators will be on in this case And since Q24 is turned off because of the de creased base voltage Q25 will be turned on and the center tuning indicator light up Furthermore C77 is charged up via R99 resulting in Q26 being turned on thereby lighting up the Quartz Locked indicator LED SX 3900 SCHMITT CIRCUIT 018 FM MUTING SIGNAL FL TUBE ICLPASOO7 AI ms TUNING our Fig 4 12 Tuning Indicator Circuit
36. 0 400 100k FU3 4 AWR 211 L awm z26 2 as ao 901 102 25 1775 610 TURNOVER Hz 2X 4k 517 POWER FUSE 5 1 2 106 SP A SP B 003104 2SA979 OF ASK 507 C N IN Pus 51 2 FILTER 159 ON OFF aaa ct 01 11 151555 300 pii AEL 047 0105 106 25C2291 3 BkHz a 0 017 AC280 D2AS 2 BV Seen 107 108 511 3 4 FILTER kHz ON OFF sa a eee p KZL 140 oe ani 112 2sA750 Si2 FM MUTING ON OFF Bas J AC POWER CORD A PLC 917 118 d ib ee d H 07 10 10E2 evsoo A is MR S12 2 FM DE EMPHASIS 25ys ON OFF 2 177 513 DIMMER ON OFF T i Sr biz n AEL 029 lt AUX R46 S 5 Bam A amp RN 50 DIS MZ 130 91134116 250400 S14 SPEAKERS A ON OFF L L Q Di4 MZ 110 SWITCH Ass 014 190 y 15 SPEAKERS B ON OFF iz s S a et Saag 56 1 SPEAKERS SP A ON OFF is z 9121122 2549044 IR s 1 2 2SA97 e lbs 2 5 054 2SCITTSA Im UNES Ans 9422 o gm 0123424 25 1914 WMO S16 2 SPEAKERS SPB ON OFF 05 6 25C1885 m H dy i KO Q 125 726 2s 2575 OP m POWER ON GFE 97 8 254912 UNSMITCHED 2 0140 25 1384 us 730 A 72 ER The underlined indicates the switch position 200W SEMEN pium e Ee Lag A A EE sie Sener ae i pc nn ze RE Q sns Oras SI REAY Fr MICRO A NS D 1355 136 25A985A 200 AEX 001 I Nari
37. AAD 226 Knob TUNING AAA 065 Knob LOUDNESS ii AAD 227 mm Knob MODE MUTING AAD 139 Knob VOLUME AAB 238 Knob BALANCE AAB 239 Lamp with wires AEL 069 Lamp with wires AEL 095 Lamp with wires AEL 069 Tuning shaft assembly AXA 260 Push switch LOUDNESS ASG 230 Lever switch MUTING 20dB ASK 152 4 gang variable resistor VOLUME ACW 304 Lever switch MODE ASK 152 2 gang variable resistor BALANCE ACT 133 Remote lever switch TAPE MONITOR ASX 131 Remote lever switch ADAPTOR DUPLICATE ASX 128 Terminal INPUT AKB 064 Bar antenna ATB 624 H Terminal AM STEREO OUT AKB 076 Terminal PRE AMP OUT POWER AMP IN AKB 063 Terminal ANTENNA AKA 013 16 A Terminal SPEAKERS AKE 054 lm AC socket AC OUTLETS AKP 041 T power cord ADG 029 Terminal TAPE ADAPTOR AKB 063 Top Viw Rectifier assembly AWR 211 Electrolytic capacitor 15 000uF 71V ACH 210 Power transformer ATT 676 Power supply assembly T AWR 210 Bottom View Tuner assembly GWE 132 SX 3900 Speakers terminal assembly GWS
38. DAPTOR DUPLICATE CAPACITORS ASX 131 Remote lever TAPE MONITOR Part No P C BOARD ASSEMBLIES ACK 034 ACM 006 Part No Symbol amp Description DCH 070D 5 GWE 132 Tuner assembly CCDCH 010C 50 GWS 220 Switch assembly Schick aito GWX 463 Detector assembly CCDCH3201 SU AWV 008 Indicator assembly AWM 226 Equalizer assembly 35 vc Tuning capacitor TCI Ceramic trimmer C50 c 6 1 cu c21 Part No Symbol amp Description Part No Symbol amp Description CCDCH 330J 50 CCDCH 101J 50 ACG 018 CCDLH 080D 50 CCDRH 150J 50 CCDUJ 120J 50 CCDXL 080D 50 CCDSL 390J 50 CCDSL 101J 50 CCDSL 151J 50 CKDYB 102K 50 CKDYB 122K 50 CKDYF 1032 50 CKDYF 4732 50 CGB R68K 500 CGB R91J 500 CGB R91K 500 COMA 153K 50 COMA 473K 50 COSH 331J 50 CASH 7514 50 COSH 152J 50 CEANL R22M 50 CEANL 50 CEANL 4R7M 50 CEA 010M 50L CEA 3R3M 50L CEA 4R7M 50L CEA 100M 50L CEA 220M 251 CEA 470M 10L CEA 101M 10L CEA 101M 251 CEA 221M 16L CEA 331M 10L CEA 471M 16L CEA 470M 25L Note C20 52 Ceramic 390p 50V c 9 C17 C8 C10 C89 c75 C24 C49 C34 C35 C15 C67 C68 C82 C91 c99 C2 C5 C6 C13 C22 C23 C25 C32 C38 C41 C42 C44 C45 C81 C86 C87 C90 92 95 C101 C107 C26 C29 C31 C37 C39 C40 C46 C48 C74 C96 C100 C104 C106 C108 c18 c9 C102 C53 C88 C55 C57 C59 C60 C103 C63 C64 C70 C71 C65 C66
39. GWE 132 has been selected on the basis of their respective IF offset values the degree of displacement from the center IF Filters are graded into 5 ranks these being identified by color coding at the top red orange gray blue and brown When replacing filters always use filters of the same color code When placing orders for these filters designate the grade color as well as the part no SX 3900 Part No Symbol amp Description SEMICONDUCTORS ATF 073 F4 F5 FM low pass filter Part No Symbol amp Description ATF 105 F6 AM ceramic filter ATF 038 FZ AM IF filter HA12017P 01 02 SWITCHES SWITCHES Part No Symbol amp Description _ Part No Symbol amp Description ASX 133 1 Remote slide TAPE MONITOR ASK 152 51 Lever TONE ASX 134 52 Remote slide DUPLICATE ASE 125 52 rotary 200 400 ASX 130 53 Remote slide ADAPTOR ASE 126 S3 Slide rotary 2K 4K ASK 152 54 S5 Lever MODE MUTING Parts List of Switch Assembly GWS 221 OTHERS v Part No Symbol amp Description SWITCHES Part No bol amp Descripti AKA 013 Terminal ANTENNA TS Symbol en AKB 063 Terminal TAPE ADAPTOR ASG 229 S4 Push FILTER ASG 229 55 Push FM MUTING OFF ASG 230 S6 Push BRIGHT DIM Parts List of Switch Assembly GWS 220 Part No Symbol amp Description ASG 230 56 Push switch LOUDNESS RD PM DOO J R301 R306 COMA 473K 50 C301 C302 CCDSL 151J 50 C303 C304 Parts List of Tone Amplifier Assembly GWG 140
40. ator Assembly AWV 008 CAPACITORS Part No Symbol amp Description ACM 010 Ceramic trimmer 473 50 c1 c2 CEANL 010M 50 C3 C4 CEANL 4R7M 50 C5 C6 332J 50 C7 C8 CEA 470M 16L co CEA 101M 25L CKDYF 1032 50 CKDYX 473M 25 CEA 471M 10L CCDCH 101K 50 CCDCH 020C 50 CKDYF 4732 50 CCDSL 101K 50 CEA 221M 16L CEA 010M 50L Note 12 C14 C17 C21 C28 C13 C15 C25 C27 C29 C30 C16 C32 c22 c24 c31 C34 C36 C35 c37 C43 When ordering resistors convert the resistance value into code form and RESISTORS then rewrite the part no as before Part No Symbol amp Description ACP 007 VR1 VR2 Semi fixed RD PM ODO J SEMICONDUCTORS R1 R33 R35 R63 Part No Symbol amp Description TA7318P A a HA12010 02 03 M54451P Q4 PD5009 a5 28 2575 06 010 25 945 28C461 B au 2 1K261 D1 D4 OTHERS Part No Symbol amp Description T24 028 L1 L2 Choke coil AAV 007 vi Fluorescent indicator tube AAV 008 v2 Fluorescent indicator tube ASS 011 xi Crystal resonator VCZ30POBOFMC Parts List of Equalizer Assembly AWM 226 CAPACITORS Part No Symbol amp Description CEANL 4R7M 50 CEA 470M 50L C3 C29 C30 C1 C2 C17 C18 Part Symbol amp Description Part No SX 3900 Symbol amp Description CEA 470M 10L CEA 471M 6L CEA 220M 50L CCDSL 220K 50 CCDSL 181K 50 CCDSL 221K 50 683K 50 COPA 122G 50 COPA 183G 50 COPA
41. eak move the spring to the projection B Dial pointer connection 8 ADJUSTMENTS 8 1 AUDIO SECTION Power Amplifier Turn VR3 VR5 L and VR4 VR6 R fully around in the counter clockwise direction but set VR1 L and VR2 R to the center positions Without any load or input signal tum the POWER switch ON DC Balance 1 Adjust VR1 L for OV to within 30mV between terminal No 30 and ground 2 Adjust VR2 R for within 30mV between terminal No 29 and ground Idle Current 1 Adjust VR3 L for 56mV between terminals No 12 and No 11 2 Adjust VR4 R for 56mV between terminals No 9 and No 10 3 Adjust VR5 L for 70mV between terminals No 12 and No 11 4 Adjust VR6 R for 70mV between terminals No 9 and No 10 Power transformer SX 3900 Output Power Indicator Calibration 1 Apply a 1kHz signal to the POWER AMP IN terminals or any other input power amplifier input terminals 2 Adjust the level of this input signal so that the voltage on the output terminals SPEAK ERS read 8 95V rms 3 Adjust VR1 L and VR2 R so that the out put power indicator read 10 watts VR2 VRI Indicator assembly 12113029 10 9 Fig 8 1 Power amplifier adjustments 19 8 2 TUNER SECTION FM Tuner e Connect the FM SG FM signal generator to the FM ANTENNA 3009 terminals via a 300
42. el increases And since these comparators apply the voltages to the output power indicator segments each succes sive segment will light up in turn as the input level rises a SX 3900 Frequency Display Frequencies received by the SX 3900 are dis played in digital form by fluorescent indicator tube FL tube Each digit employs up to 7 seg ments g see Fig 4 8 te display all numerals from 0 to 9 with the exception of the left hand digit which employs only 2 segments b and c Fig 4 8 7 Segment Digit Display The signal source during both AM and FM recep tion is the local oscillator The signal is passed via a buffer amplifier FET to the prescalar IC M54451P where it is subjected to frequency divi sion 1 8 for AM and 1 80 for FM before being applied to the frequency counter IC PD5009 This IC is responsible for the dynamic drive of the 7 segment 5 digit display each digit being turned on according to time shared sequential scanning 1 M54451P IC PD5009 AM LOCAL OSC SIGNAL PRESCALAR COUNTER 979 op 05 04 03 02 Di ANODES FM LOCAL OSC SIGNAL CRYSTAL OSC 5 12MHz FM AM SELECTION SIGNAL FL TUBE Fig 4 9 Frequency Display Circuit OMPRESSOR Lepr 2048 IGNA compaessor E ps E I H 40 dB gt D IC HA12010 orrser
43. er Amplifier Circuit 10 stage off noting that there actually is a slight de crease in current For the negative portions of the signal Q2 and Q4 are operated in the same man ner thereby preventing the NPN power stage from being cut off 4 4 DISPLAY CIRCUIT Power Indicator Circuit The SX 3900 output power indicators feature fluorescent indicator tube FL tube In this tube thermionic emissions from the cathode are ac celerated into the fluorescent substance of the segmental anodes resulting in the emission of light This tube is used to indicate numerals letters and other symbols An outline of the FL tube drive circuit is shown in Fig 4 7 The output circuit signal is first passed through a low pass filter and a compressor circuit before being applied to pin no 6 4 of the IC TA7318P A The compressor circuit makes use of the non linearity of rising portion of the diode s characteristics to contract the signal dynam ic range by 20dB The IC contains a detector cir cuit compressor 40dB and peak hold circuit for both left and right channels The dynamic range of the signal is thus contracted by 60dB to obtain a peak held DC voltage The output power indicator segments of the FL tube are driven by the HA12010 ICs one for each channel equipped with 12 pairs of voltage com parators These comparators are biased at increas ing levels so each comparator will commence to operate separately as the input lev
44. g two tape decks TAPE MONITOR SWITCH Employ for tape playback or to monitor a recording in progress 1 Playback or monitoring of a tape deck con nected to the TAPE 1 jacks SOURCE Be sure to set to this position when not using the tape deck for playback and moni toring 2 Playback or monitoring of a tape deck con nected to the TAPE 2 jacks NOTE When listening to records or broadcasts be sure to set this switch to SOURCE Sound will not be obtained from speakers if it is set to 1 or 2 BALANCE CONTROL Use this control to balance the volume of the left and right channels First however set the mode switch to MONO If the sound appears to be louder on the right it means that the volume of the right channel is higher Turn the balance control to the left and adjust Con versely if the sound appears to be louder on the left it means that the volume of the left channel is higher Therefore turn the balance control to the right and adjust After adjusting return the mode switch to STEREO 4 MODE SWITCH Use this switch for selecting mono or stereo perform ances STEREO Set to this position for normal operations MONO When set to this position the left and right channel signals will be mixed and repro duced monophonically from both speaker systems VOLUME CONTROL Use this control to adjust the output level to the speakers and headphones Turn it clockwise to increase the output level No sound w
45. heat generated in R1 will cause Microtemp to below thereby opening the primary circuit When the POWER switch S1 is tumed OFF the relay driving circuit is opened thereby opening 52 and the primary circuit RELAY Fuse s2 MICROTEMP Power 3 Mus pes RI AC Fig 4 16 Surge Current Suppressor Circuit 15 6 PARTS LOCATION Front Panel View Fluorescent indicator tube AAV 008 BRIGHT DIM AAD 227 Knob FILTER FM The mark found on some component parts indicates the importance of the safety factor of the part There fore when replacing be sure to use parts of identical designation Front panel assembly ANB 861 AAD 226 Knob BASS TREBLE Knob SPEAKERS Wie il 1 TURNOVER y h AAB 239 Wooden cover 087 Knob POWER TONE ADAPTOR DUPLICATE TAPE MONITOR AAD 139 Front View with Panel Removed Push switch BRIGHT DIM ASG 230 Dual push switch ASG 229 Lamp with wires AEL 047 ON Phone jack PHONES AKN 030 Remote switch SPEAKERS ASX 137 A Lever switch POWER ASK 507 Slide rotary switch BASS TURNOVER ASE 125 2 gang variable resistor BASS ACT 134 Lever switch TONE ASK 152 2 gang variable resistor TREBLE ACT 134 Slide rotary switch TREBLE TURNOVER ASE 126 Rear Panel View Fluorescent indicator tube AAV 007 Knob FUNCTION
46. i2 Lamp with wires AEL 065 AEL 065 SWITCHES Part No Descripti Remark Sum ida KU type S G type b 517 Lever POWER ASK 507 ASK 508 Remote lever ADAPTOR DUPLICATE ASX 128 ASX 128 Remote lever TAPE MONITOR ASX 131 ASX 131 A Line voltage selector renee AKX 063 P C BOARD ASSEMBLIES T Part No bol Description Remarks m dia KU type S G type Tuner assembly GWE 132 GWE 132 Switch assembly GWS 220 Gws 220 Detector assembly GWX 463 GWX 463 Indicator assembly AWV 008 AWV 008 Equalizer assembly AWM 226 AWM 226 Tone amplifier assembly GWG 140 GWG 140 Switch assembly Gws 221 GWS 221 Power amplifier assembly AWH 097 AWH 097 Power supply assembly AWR 210 AWR 210 Speakers terminal assembly GWS 222 GWS 222 Switch assembly GWS 223 GWS 223 Headphones jack assembly GWK 146 GWK 146 Rectifier assembly AWR 211 AWR 214 De emphasis assembly ee AWS 147 OTHERS Part No bol Description Remarks KU type S G type Act Ceramic capacitor ACG 001 ACG 001 C2 C3 COMA 224K 250 COMA 224K 250 ul Power transformer ATT 676 ATT 682 T2 Power transformer ATT 675 ATT 681 Bar antenna ATB 624 ATB 624 A AC socket AC OUTLETS AKP 041 AKP 041 A AC power cord ADG 029 ADG 049 Terminal AM STEREO OUT AKB 076 AKB 076 Transistor socket AKH 010 AKH 010 Lamp socket AKK 005 AKK 005 Jumper plug AKM 004 AKM 004 L PACKING Part No Symbol Descripti Ri escription Ko
47. ied to the variable capaci tance diode in the local oscillator thereby correct ing the oscillator frequency to obtain a constant IF i e a constant tuned frequency Since the central frequency of the crystal detec tor is regulated by the crystal resonator tuned frequencies of extremely high stability are ob tained 1 PA3007 A LeF2 FM MUTING 8 x ote AMP WITH LIMITER SCHMITT CIRCUIT Fig 4 1 Quartz Lock System Limiting the Locking Range If the quartz lock range is too wide it will overlap with strong adjacent broadcasting fre quencies and result in considerable tuning diffi culties A DC amplifier is therefore used as a limiter limiter action by NFB circuit zener diodes which restricts the voltage applied to the variable capacitance diode thereby limiting the quartz lock range A DC voltage appears at pin no 13 of the IF system IC PA3007 A when the antenna input level drops below 54V or when the tuned fre quency has been detuned by more than 100kHz This DC voltage FM muting signal is applied to the gate of Q2 FET via a Schmitt circuit result ing in the FET being turned on and the quartz lock circuit being turned off Multiplex Decoder The recently developed multiplex decoder IC PA4006 A combines MPX decoding with muting functions in a single IC thereby handling the functions of the more conventional MPX IC PA1001 A and AF MUTING IC PA1002 A
48. ill be heard if you set it to The scale is graduated in dB which indicate the attenuation when the maximum output level is OdB 2 MUTING SWITCH Set this switch to the 20dB position to attenuate the audio output indicated by the volume contro by 20dB There is no need to adjust the volume control if you use this switch when turning down the audio output tem porarily and when changing over records or tapes 3 HEADPHONE JACK Plug the headphones into this jack when you want to listen through your stereo headphones Release both speaker switches if you want to listen to the sound through your headphones only SPEAKER SWITCHES Depress the switch corresponding to the speakers con nected to the SPEAKERS terminals A or B on the rear panel You can depress both of these buttons to listen to the sound from two pairs of speaker systems at the same time SX 3900 LOW FILTER SWITCH 15Hz Depress this switch in the event that turntable rumble recording cutting noise or other low frequency noise becomes objectionable Attenuation in the frequency band below 15Hz is 6dB octave HIGH FILTER SWITCH 8kHz Depress this switch if record scratch noise or other high frequency noise becomes objectionable Attenuation in the frequency band above 8kHz is 6dB octave 07 POWER METER This meter allows you to read out the rated power level on the fluorescent display tube when speakers with a nominal impedance of 8ohms are connected t
49. illator This oscillator isa voltage controled oscillator employing a vari cap variable capacitance diode When the quartz lock system refer to Quartz lock system is not in operation a constant voltage is applied to the diode IF Amplifier and Detector These employ 3 ICs and 3 dual element ceramic filters The IC HA1201 of the first 2 stage con stitutes a single stage differential amplifier current limiting limiter The IC PA3007 A in the third stage an improvement on the former IF system IC PA3001 A includes an IF limiter amplifier quadrature detector meter drive and other cir cuits Performance in terms of distortion S N ratio delay characteristics and other parameters shows a marked improvement in comparison to the PA3001 A Quartz Lock System The quartz lock system featured in the SX 3900 stereo receiver is a frequency servo control system employing a crystal resonator Any displacement in the intermediate frequency IF is detected as a DC voltage by the discriminator equipped with a crystal resonator resulting jn the local oscillator frequency being corrected and subsequently locked This extremely stable frequency servo con trol system thus ensures that tuned frequencies remain tuned securely for as long as required When the IF signal appears at pin no 17 of the FM FRONT END IF system IC PA3007 A it is amplified and ap plied to a crystal detector see Fig 4 1 which con sists of di
50. ing to the D3 time division pulse timing thereby placing the segments under dynamic drive In addition the AM and FM indicators in the frequency display section are lit according to the D5 timing while the kHz and MHz indicators are lit according to the D1 timing TUNING Indicator Circuit The TUNING indicator consists of a center tuning indicator which lights up when a broad casting station frequency is properly tuned and 2 detuning direction indicators which indicate the direction in which the station has been tuned away from The corresponding drive circuits are out lined in Fig 4 12 The TUNING indicator is activated once the station has been tuned to within 100kHz of the center frequency This is because Q16 is turned on and Q21 turned off resulting in the detector differential amplifier Q19 amp Q20 being turned off and Q24 being turned on by the FM muting signal appearing at pin no 13 of the IF system IC PA3007 A and passed via the Schmitt circuit Q17 amp Q18 when the station is tuned away by more than 100kHz The DC voltage on pin no 4 of PA3007 A describes an S curve when tuning to and away from a particular broadcasting frequency the voltage on pin no 2 serving as the reference level This DC voltage is amplified by the differential amplifier Q19 amp Q20 and then applied to a polarity detec tor switch circuit Q22 amp Q23 When tuning to a frequency from the high fre quency side or tuning away from
51. manual is applicable to the S G type please refer to the KU type service manual with exception of this supplements SPECIFICATIONS The specifications for S G type is the same as the KU type except for fol lowing sections Miscellaneous Power Requirements AC 110 120 220 240V switchable 50 60Hz Power Consumption 310W Weight without package 21kg 46 Ib 5 oz CONTRAST OF MISCELLANEOUS PARTS e The mark found on some component parts indicates the importance of the safety factor of the part Therefore when replacing be sure to use parts of identical SEMICONDUCTORS designation Pr Part No Symbol Description Remarks 01 04 Transistor 2502526 28C2526 05 08 Transistor 2541076 2SA1076 FUSES Part No Symbol Description Remarks KU type S G type Fuse 10A AEK 305 AEK 110 Fuse 2 5A AEK 102 AEK 102 Fuse 1A AEK 106 AEK 106 Fuse 1A AEK 106 AEK 106 Fuse BA AEK 108 LAMPS Part No Symbol Description Remarks KU type S G type PLI Lamp wedge type AEL 029 AEL 029 PL2 Lamp wedge type AEL 029 AEL 029 PL3 Lamp wedge type AEL 029 AEL 029 PL4 Lamp with wires AEL 069 AEL 069 PL5 Lamp with wires AEL 069 AEL 069 PL6 Lamp with wires AEL 095 AEL 095 PL7 Lamp with wires AEL 069 AEL 069 PL8 Lamp with wires AEL 069 AEL 069 PLO Lamp with wires AEL 047 AEL 047 PLIO Lamp with wires AEL 047 AEL 047 PL11 Lamp with wires AEL 075 AEL 075 PL
52. me H awe a MM po iL e MESE e an 97 LH sreseo Tel ss mo rs pm jc tuai200 TUNER b peel Tu yrs WNOCATOR s romt so E moicaror onve er ewe se Audio Section CERAMIC 1 FILTER Ly FLUORESCENT INDCATOR TURE rer la IC 54451 PRESCALAR FM AM ose 009 TIME DvisioN 7 SEGMENT DECODER vios HY Ft one TUNNG INDICATOR FREQUENCY DISPLAY IE c Zu I am SIGNAL INDICATOR pe ot T Je dus en TPF wr vom N en a eee Eo po ree IE sonen moara i a zm 4 CIRCUIT DESCRIPTIONS 4 1 FM TUNER SECTION Front End The FM front end of SX 3900 includes a 4 ganged tuning capacitor a dual gate MOS FET equipped 1 stage RF amplifier and a modified Clapp circuit local osc
53. n capacity u F voltage V unless otherwise noted p pF Indication without voltage is 50V except electrolytic capacitor cm o 5L f 22 23 24 25 26 27 28 29 30 54 5352 27 uml 3 VOLTAGE CURRENT 9 Oe UD t Aav 00r Signal voltage at 120 W 120 B0 output 1kHz R95 ger A DC voltage V at no input signal S ye ee cons O w K ie CT a 9 gt lt mA DC current at no input signal VS 10 47 i 7 915 25 1919 NJM4558DV Ta m omi VE mu owe 326 4 OTHERS C137 mp Signal route en Gr justing poi AY PLS 12 pu RLTIAME PESLEMI EL gt A Adjusting point 1 d 8V50mA Ad PLi2 100k AWM 226 The mark found on some component parts indicates the im AEL 0698 tock Q14 16 v 21 R73 pte gt 50 02426 TA wai 47 portance of the safety factor of the part Therefore when replacing C PLE 8V50mA AEL 065 2SC2575 A RMA 15 821330 POWER SUPPLY Assy AWR 210 PES c be sure to use parts of identical designation 922 20 la Q4 2scieas 1 soma lt s ver Rat A11 Q1 2 25K34 ato Q5 2SA912 2 H This is the basic schematic diagram but the actual circuit may vary r S PLE Sv SON 2SD313P 2502575 Q6 25B682 due to improvements in design AWR 210 PHONO 245 PUE mA R98 82 RIO 005196 I D109 110 SWITCHES SINE S1
54. nce BASS AND TREBLE CONTROLS Use these controls to adjust the bass and the treble If you set the tone switch to ON and turn the bass control to the right from its center position you will be able to emphasize the sound in a frequency range which is lower than that selected by the bass turnover switch Conversely turning this control from the center position to the left will attenuate the sound You can use the treble control to adjust the sound in a frequency higher than that selected by the treble turn over switch TONE SWITCH Set this switch to ON when adjusting the bass and treble controls When set to the OFF position the tone control circuits are disengaged and frequency response is flat This function is convenient for checking phono cartridge and speaker tone quality and listening room acoustics 8 TREBLE TURNOVER SWITCH Use this switch to change over the frequency in which the sound adjustment with the treble control is starting to take effect Select 2kHz or 4kHz in accordance with the characteristics of your listening room and of your speakers and with your general preference amp ADAPTOR SWITCH Set this switch to ON when reproducing sound from an optional component which is connected to the ADAP TOR jacks Always set it to the upper position if you are not using a component with these terminals TAPE DUPLICATE SWITCH Set this switch to ON when you want to duplicate or edit a pre recorded tape usin
55. ng of 4 PN junctions formed by Q3 D3 and Q4 and VR1 With R1 and D1 ensuring a constant flow of current the base of Q1 and point X may be brought to the same level on an AC basis level fluctuations due to the signal by a simple shift in DC level Furthermore Q1 may be considered emitter follower with R3 as the emitter resistance When the voltage across points Y and X is in creased by the positive portion of the signal ap plied to this circuit it becomes the input signal of this emitter follower Q1 Since the emitter follower voltage gain is practically 1 a voltage more or less equal to that of the input signal that is the voltage increase across points Y and X js produced at R3 And the R3 voltage is the volt age applied across the base and collector of Q3 which forms part of the power stage bias circuit So the bias voltage applied to Q3 will be in excess by the same amount the voltage across points Y and X increased by positive portion of the signal above the voltage level when no signal is being applied Consequently the increase in voltage across points Y and X cancels the decrease in voltage across points X and Z thereby maintaining the idle current without cutting the PNP power amp PRE ORIVER Fig 4 6 Basic Circuitry of Non Switching Amplifier 820 o6 Li 81 HIGH SPEED BIAS SERVO CONTROL OUT 820 81 Fig 4 5 Pow
56. o 3SK73 Lot No oe HA1197 De MM HA12010 P G2 2SK168 HA1201 NJM4558DV Type No H toss P Lot No ri s b 25 1384 4006 250313 HA12017P TA7318P PD5009 M54451P he TW AAA SX 3900 3 4 2 72 p DEI Le Sees ee 8 9 10 11 12 NOTE The indicated semiconductors are representative ones only Other alternative semiconductors may be used and are listed in the parts list o _ TUNER Assy GWE 132 018 1SV69 TONE AMP Assy m 06 7 HAI201 SWITCH Assy 1 2 TONE AMP Ass y R35 1 5k c33 SPEAKER TERMINAL p 2 Sg aa GWS 22 GWG 140 e TREBLE 1050 le Gws 222 INDICATOR Ass y AWV 008 Qi TATSIBP A sa x AAV O07 v2 1 au saus e 47 50 mu 14 SPEAKER A q I H AAV 008 ASG 230 a H f i SPEAKER A 7 ar ON f 2 R B n RS E 750 1 5K c si BAL 3SOON Kr 100k 9 53 H SO TURNOVER oon 0 B yrany 13 2 pati peo UNBAL 752 4 a 3a LO end ACT 134 a 2 SPEAKER R17 i fe A Se O i A db Bik 04 25 906 1 1 1 c34 150p c35 150p VR3 S PARATION ADJ C92 048 SWITCH Assy GWS 220 R36 8 2 S6 LOUDNESS R305 1M C303 R30 6230 7 50 esk pied am d A
57. o X1 in the detector 5151 Di assembly GWX 463 is available in 3 different types correspond 551518 D2 ing to the IF offset values of the FM ceramic filters ATF 104 symbol nos F1 in the tuner assembly GWE 132 These may be identified by the different colored dots red blue OTHERS orange at the head When replacing crystal resonators check that the matching requirements listed in the following table are Part No Symbol amp Description met ASR 069 Relay Crystal resonator ASS 012 FM ceramic filter ATF 104 AEX 001 F1 Temperature sensitive fuse Red Red blue or orange also permissible Blue Blue or brown Orange Orange or gray Parts List of Speakers Terminal Assembly GWS 222 Part No Symbol amp Description A AKE 054 Terminal SPEAKERS ASX 137 Remote slide switch Parts List of Switch Assembly GWS 223 Part No Symbol amp Description ASX 135 Remote push switch Parts List of Headphones Jack Assembly GWK 146 Part No Symbol amp Description AKN 030 Phone jack PHONES RS2P 331 R1 R2 40 12 EXPLODED VIEW Exterior Components NOTES Parts without part number cannot be supplied The mark found on some omponent parts indicates the importance of the safety factor of the part Therefore when replacing be sure to use parts of identical designation SX 3900 Key No _ Part No Description Key No Part No Description 1 DCK40P150FZK
58. o the speaker terminals DIAL POINTER This pointer indicates the broadcasting stations FM STEREO INDICATOR This indicator lights up when receiving an FM stereo program if the FM muting off switch is released QUARTZ LOCKED INDICATOR This indicator lights up after the optimum tuning point has been obtained and displays that the receiving state is stabilized by the built in quartz lock circuit SIGNAL INDICATOR This indicator lights in sequence from left through right during the tuning of an AM or FM broadcast in accord ance with the strength of the signals being received The optimum tuning point is where the maximum number of indicators light TUNING INDICATOR When tuning in an FM station the optimum reception point is indicated when the center indicator lights up When the left indicator has come on rotate the tuning knob slightly clockwise When the right indicator comes on rotate the knob slightly counter clockwise FREQUENCY DISPLAY This indicates the frequency which is tuned With FM reception the letters FM appear on the left of the display and MHz on the right With AM recep tion AM appears on the left and kHz on the right These change when the function selector position is changed TUNING KNOB Use this knob to tune in to broadcasting stations amp FM MUTING OFF SWITCH When this switch is released and an FM broadcast tuned in
59. odes connected in parallel in a series resonance circuit equipped with a crystal resona tor The resonance frequency is the same as the IF frequency 10 7MHz which means the impedance at this time will be minimal resulting in the out put being reduced to a minimum level If the input frequency increases the reactance of the capaci tance stage C is reduced and the reactance of the inductance stage L increased resulting in AM detection by D2 which leaves the positive portion of the IF signal If the input frequency decreases L stage reactance is decreased and C stage reac tance increased resulting in AM detection by D1 which leaves the negative portion of the IF signal The L stage and C stage reactances increase as the degree of detuning in the respective directions is increased resulting in a subsequent increase in the detector output By thus attaining S curve characteristics FM detection becomes possible Since the IF signal is an FM signal frequency devia tion due to modulation it will be symmetrical about a central axis And if the central frequency is equal to the resonance frequency the detector out put DC level will be zero If however there is any displacement in the central frequency frequency deviation in respect to the detector will become asymmetrical resulting in the generation of a DC voltage This DC voltage is passed through LPF1 IF filter and LPF2 AC filter to form a correc tion voltage which is appl
60. r lemarks Packing case AHD 756 AHD 757 Inside packing AHC 042 AHC 042 Side pad AHA 247 AHA 247 Cardboard spacer AHB 089 Rear pad AHA 251 AHA 251 FURNISHED PARTS mbol Description Remark i KU type S G type Operating instructions ARB 354 ARB 356 T type FM antenna ADH 002 ADH 002 50 Parts List of Rectifier Assembly AWR 214 CAPACITORS Part No Symbol amp Description ACG 004 2 Ceramic 0 01 150 ACH 210 C3 C4 Electrolytic 15000 71V ACG 001 C5 Ceramic 0 01 250V Note When ordering resistors convert the resistance value into code form and RESISTOR then rewrite the part no as before Part No Symbol amp Description ACN 019 RI Wire wound 3 3 20W SEMICONDUCTORS Part No Symbol amp Description 5151 Di S5151R D2 OTHERS Part No Symbol amp Description _ ASR 069 Relay AEX 001 F1 Temperature sensitive fuse Parts List of De emphasis Assembly AWS 147 Part No Symbol amp Description COSH 7513 50 2 COSH 152 50 C3 C4 ASH 015 51 Slide switch S5X 3900 5 G sx 3900 S G 6 7 8 10 12 DIAGRAM FOR S G TYPE The indicated semiconductors are representative ones only Other alternative semiconductors may be used and are listed in the parts list SCHEMATIC
61. rs have been arranged accordimg to the grade of FM ceramic filter color coded into 5 ranks as shown in the following table FM ceramic filters F1 F3 Cut Connect Cut Cut Connect Cut Connect Cut Cut Cut HEADPHONE JACK Assy 146 MUTING Tu 7 BRIGHTNESS i SER Y 56 TURNOVER 3 TONE AMP Assy GWG 140 10 SX 3900 POWER AMP Assy 097 RECTIFIER Ass y AWR 211 181555 ont 152076 7 E E 4 s 14 2SC2526 Q5 8 25 1076 T1 AC120V 60Hz SPEAKER TERMINAL Ass y GWS 222 FUSE Assy Eur AKERS A Beni SWITCHED 100W 34 11 PARTS LIST NOTES e When ordering resistors first convert resistance values into code form as shown in the following examples Ex 1 When there are 2 effective digits any digit apart from 0 such as 560 ohm and 47k ohm tolerance is shown by J 5 and K 10 5602 56x 10 561 RD4PS HOD 7 47x10 473 0 50 ORS ND 2 RN2H 10 010 RSIP Ex 2 When there are 3 effective digits such as in high precision metal film resis tors 5 62k2 562x10 5621 RNUSR aur e The amp mark
62. side of the wooden cover Bottom Plate Remove the thirteen screws to detach the bottom plate Front panel 4 6 SURGE CURRENT SUPPRESSOR Since the SX 3900 employs a large toroidal power transformer and two 15 0004F capacitors in the power supply circuit the sudden surge of current when the power supply is turned on may reach several hundred amperes The surge current suppressor circuit used to reduce this sudden surge is shown in Fig 4 16 When the POWER switch S1 is OFF i e no supply of AC power the relay contact S2 is open But when this switch S1 is turned ON the sudden surge of current is passed through R1 thereby greatly reducing the flow of current When the output DC voltage of the power supply circuit reaches a certain prescribed level S2 will close and R1 consequently be by passed The time required for this to occur however is considerably shorter than the time required for the muting circuit to operate when the power supply is turned SX 3900 Front Panel Remove all the knobs by pulling Remove the two screws from the top edge of the front panel Remove the two nuts from the control shafts Wooden cover Bottom plate on so there is no undue effect upon normal opera tion of the receiver Microtemp is a temperature sensitive fuse coupled to R1 If S2 fails to close due to an abnormality in the power supply circuit or relay the
63. stance and equalizer element impedance High voltage gain is provided in the following stage by a bootstrap cir cuit The output stage is a complementary sym metrical SEPP circuit The high voltage utility factor of the SEPP circuit provides a high maxi mum output voltage Dynamic range of the equalizer amplifier is therefore wide and overload input level at 0 005 distortion is 300mV rms at 1kHz Fig 4 3 Phono Equalizer Amplifier Tone Control Fig 4 4 shows the basic configuration of the circuit This circuit is an NFB type tone control with IC HA12017P Tone control BASS TREBLE is accomplished by providing the tone amplifier NFB circuit with a frequency selective characteristic The capaci tance of C1 C4 are changed by the TURNOVER switches by adding another capacitors in parallel to provide selection of the frequency The NFB circuit is changed to a flat frequency characteristic when the TONE switch in the OFF position Fig 4 4 Tone Control Circuit Power Amplifier Section e Amplifier Circuit The basic circuit arrangement of the power amplifier is shown in Fig 4 5 The first stage is a differential amplifier comprising PNP twin transis tor Q2 the load circuit of which is a current mirror employing an NPN twin transistor Q3 The current mirror provides push pull operation in this stage which serves to cancel even harmonics and further increase gain Q1 in the input circuit absorbs outflow
64. th Food 2 AMM 087 Wooden cover assembly 12 VBZ40P080FMC 3 VBZ30P080FMC 13 AEC 178 Foot assembly 4 ANB 861 Front panel assembly 14 VTZ40P120FMC 41 AAD 226 Knob A 15 Bottom plate 42 AAD 227 Knob B 5 WA92F140U100 6 NK90FUC 7 AAD 139 Knob for lever switch 8 239 Knob BASS TREBLE TURNOVER BALANCE 9 AAB 238 Knob VOLUME 10 065 Knob Tuning 41 Interior Components NOTES e Parts without part number cannot be supplied e The mark found on some component parts indicates the importance of the safety factor of the part Therefore when replacing be sure to use parts of identical designation Key No _ Part No Description Key No Part No Description 1 GWE 132 Tuner assembly 46 ASX 131 Remote switch 2 GWS 220 Switch assembly 47 Remote belt 3 GWX 463 Detector assembly 48 Remote belt 4 AWV 008 Indicator assembly 49 Remote belt 5 AWM 226 Equalizer assembly A 50 ACG 001 Ceramic capacitor 6 GWG 140 Tone amplifier assembly 81 AKP 041 AC socket AC OUTLETS 7 GWS 221 Switch assembly 52 ADG 029 AC power cord 8 AWR 210 Power supply assembly Terminal GND 9 945 222 Speakers terminal assembly AKB 076 Terminal AM STEREO OUT 10 GWS 223 Switch assembly ATT 676 Power transformer 11 GWK 146 Headphones jack assembly 56 624 Bar antenna 12 AWR 211 Rectifier assembly 87 675 Power transformer Fuse holder assembly 58 AEL 029 Lamp wedge type 14 Dial
65. the muting circuit is activated inside to suppress the annoying interstation noise between the broadcasting frequencies for noise free reception When the broadcast ing station is far away or when receiving a station in a fringe area set the switch to the OFF position and then tune in If there is a broadcasting station with a strong signal level on the air next to a station whose program you want to receive you may not be able to tune in satisfactorily because the sound will be drowned out by the stronger signals In cases like this set the FM MUTING OFF switch to OFF depressed position and tune in The muting circuit does not work when the tuner is receiving AM broadcasts If tuning has been performed after the FM MUTING OFF switch has been depressed and a station selected the quartz locked circuit is set to the OFF mode and the LOCKED indicator does not light FM 25uS SWITCH Depress this switch when listening to a Dolby FM broadcast otherwise keep this switch at the released position BRIGHTNESS SELECTOR Use this switch to select the brightness of the power meter and the frequency display BRIGHT When using the receiver in daylight or other bright locations DIM At night or in dark locations when the exist ing brightness is too high FUNCTION SELECTOR Depress the function switch which corresponds to the program source Turn the volume control down first before selecting a different function switch while the so
66. und from one program source is being reproduced FM Depress this switch for FM broadcasts AM Depress this switch for AM broadcasts AUX Depress this switch when listening to an audio component connected to the AUX jacks PHONO 2 Depress this switch when playing a record on the turntable connected to the PHONO 2 jacks PHONO 1 Depress this switch when playing a record on the turntable connected to the PHONO 1 jacks NOTE Only one function switch should be depressed at a time LOUDNESS SWITCH When listening to a performance with the volume control turned down depress this switch and the bass and treble will be accentuated When the volume is low the human ear finds it harder to hear the bass and treble than when the volume is high The loudness switch is thus designed to compensate for this deficiency By depressing this switch the bass and treble come through much more strongly and the sound takes on a punch even when the volume control is turned down The word Dolby is a trademark of Dolby Laboratories Inc 3 BLOCK DIAGRAM Tuner Section SX 3900 aoa fee fusus o4 AM o IC PA3007 A ic 4006 m runer actarzon gre T oral pm NP

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