User manual PIONEER SX-3700 service manual

[. . . ] rilf , a EefvicecTlanual a sSx-37cIcI STEREO RECEIVER sx-8ecl ()rqoruErr MODELSX-3700 IN DISTINGUISHED FOLLOWS. 120V only '| 20V only 11OV 12OV , , 22OV , end 24OV(Switchabls) 11OV 12OV 22OV, and 240V (Switcha ) ble . Military mod6l Ramarks KU KC e This servicemanual is applicableto the SX-3700/KU. For servicingof the other types, please refer to the additional servicemanual. CONTENTS 1 . [. . . ] When the power is switched off, C4 is discharged rapidly via Db and R7, resulting in Q6 being tumed off and the relay contacts being opened. 410 below consists of a Wheatstone bridge with the load RL forming one of the arms. Q3 is biased by the potential difference betyyeen diametrically opposite comers of the bridge circuit. If the RL value drops below a certain fixed level, Q3 will be tumed on due to forward biasing. The charge on C4 in the relay drive circuit will thus be discharged via D3 and Q3, resulting in Q6 being tumed off and the relay contacts being opened. If for any reason a DC voltage is generated at the output, it will be detected by the DC voltage detector circuit, resulting in the relay contacts being opened to thereby protect the speakers. Rb and C2 form a low-pass filter designed to block normal signal components, thereby preventing the application of signal voltages to the bases of Q4 and Q5. If a positive DC voltage appears at the output, it is divided by R5 and R6, and applied to Q4 and Q5. Since the base of Q5 is connected to ground, this transistor will remain off due to the reverse bias applied. And since the emitter of Q4 is connected to ground, this transistor will be tumed on due to a forward bias. Consequently, the base of Q6 is grounded by Q4, resulting in Q6 being turned off and the relay contacts being opened. If a negative DC voltage appears at the output, Q4 is tumed off due to a reverse bias, while Q5 is tumed on due to a forward bias. And since a negative voltage is applied to the emitter of Q5 in this situation, Q6 is tumed off and the relay contacts ooened. F|ly driv circuit F i g . 4 - 1 0 O v e r l o a d e t e c t o Ci r c u t D r i , l ""*";. ;;;l F Powr amplifir Overload detector circuit DC voltag dstsctor circuit l[&'#bfr ll J AC powor supply t:. | ;. + R6lay driv circuit I J 4, Fig. 4-11 Protection Circu it six-37ClCl 5. DISASSEMBLY Bonnet Case Remove the four screws O on each side of the bonnet case. O to detach the Front Panel Remove the all control knobs except push knobs. Remove the two screws tp and two nuts Q from the front panel. ?^ Bonnetcase Front panel ottom plate d Fig. 5-1 Disassembly -+-\? n 6. PARTS LOCATIONS Front Panel The [, mark found on some component parts indicates the importartce of the safety factor of the part. There' fore, when replacing, be sure to use parts of identical designation. Knob (TUNING) AAA065 Front panel assembly ANB-883 Bonnet case AMM89 Push knob AAD-226 Lever knob assembly AAD-139 Front View with Panel Removed F L assembly AWV-o12 Switch assembly GWS-233 Function switch assembly AWS-149 Lead out assembly AWVOl1 , lt, Switch (POWER) ASA-507 P h o n ej a c k ( P H O N E S ) AKN{30 V a r i a b l e r e s i s t o r( T O N E ) ACT-127 Switch V a r i a b l er e s i s t o r 5 O k ( V O L U M E ) 2 ACT-126 Switch (LOUDNESS) ASK. 157 Switch (MUTING) ASK-l59 V a r i a b l er e s i s t o r1 M ( B A L A N C E ) ACT{21 ASK. 157 sx-37clcl /';^ RearPanel Bar-antenna ssembly a ATB24 I AC soctet (Ac OUTLETS] AKP{39 tl^ Terminal(AM STEREOOUT) AKB{)76 Terminal (ANTENN AKAOl4 Pin iack I AC power cord ADG{23 v2 Terminal(SPEAKER) AKEO44 AKB{63 Top View /g^ Power amp/protector assembly GWM. 159 IPower transformer ATT696 Tuner/AF assembly GWM. 160 8^ J. ' D Detector assembly GWX463 n^ 15 7. Remove the bonnet case and front panel as described in the "Disassembly" section on page 1 2. Rotate the tuning capacitor right around until the rotor blades are fully intermeshed. Secure the tuning drum back onto the tuning capacitor shaft, making sure that the securing screw I faces directly upward. Passthe cord out through the small opening in the circumference of the tuning drum (see diagram), and then take it over pulleys A, B, and C in that seouence. [. . . ] Symbol& Doscription 8111 R6 R 1 0 5 , R 1 0 6 R1 R5, R7- R93, A95 R102, A10/ R 1 0 9 , R 1 1 2 R103, R r04 Rl10 R94 ASG240 CAPACITORS S1 Poshswiich Symbol & Dsscriprion C E A2 R 2 M O L s RESISTORS c1, c2 Symbol & Doscription RDI/4PMuLilJ R D'l /2PSuirtrJ SEMICONDUCTORS Symbol& Doscription 1S1555 (1 5 2 4 7 3 ) D1 D9 R 1 R 3 , R 7 , R 8 R9 (AWV-O12) FL Assembly CAPACITORS Svmbol & D6scriorion SEMICONDUCTORS Symbol & Dsscription cEA R47 t\, 1 50L c K D Y F 3 3 2 25 0 RESISTORS Pan No. ds beforeSymbol & Descriprion VB1, VR2 Serni-fixed R1, R2 R3, R4 N o t e . cont)erl the M54451P PD5009 HA12010 2SC45A l2sc2575l 2SA733A (2SA1r00) o1 a2 o3 05-o9, o11 024 o25 029 32 sx-3700 SEMICONDUCTORS Symbol & Doscription T A 7 3 1 8 PA HA12010 LZTS'I MZ-O41 Symbol & Doscription o1 0 2 , 0 3 D1 D2 coMA 223J50 coMA 563J50 cor\rA 683J 50 C K D Y E1 0 3 K5 0 Noler OTHERS RESISTORS Symbol & Doscription c219, C220, C225, C226 c221 . C 3 l 2 ', 1'hen ordering resistors, conrert tlrc resistancevalue into code form, and then reurite lhe part no. [. . . ]