Zenith MC7031 Service Manual Download

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Summary of Contents for MC7031

Page 1: ... 0 5 1 I L L U S T R A T E D STEREO RECEIVERS MODELS MC7031 MC7041 MC7051 ZENITH RADIO CORPORATION PARTS AND SERVICE DIVISION 11000 SEYMOUR AVENUE FRANKLIN PARK ILLINOIS 60131 HF 46 22 8M CPC JUNE 1980 PRINTED IN U S A 4 00 923 972 ...

Page 2: ...eatures Page 9 General Information Page 10 Alignment Procedures Pages 11 15 Disassembly Pages 16 19 Theory and Application Pages 20 22 Parts Lists Pages 24 36 Integrated Circuit Block Diagrams Pages 38 41 Schematic Related Drawings and Exploded Views Pages 43 60 TECHNICAL APPLICATIONS INDEX Various H F series service manuals contain information relating to solid state device theory operation and c...

Page 3: ...MC3000 HF 39 6WGR91 HF 31S2 MC3000 11 HF 39 8WJR56 HF 33 MC3000 12 8WJR57 HF 33 MC4000 HF 39 12WGR58 HF 31 32S1 MC4000 11 HF 39 12WGR59 HF 31 31S1 MC4000 12 12WHR29 HF 32 32S1 MC6010 HF37 15WJR29 HF 33 33S1 34 MC6020 HF45 15WEA10 HF 29S1 30 MC6060 HF 37 15WFR51 HF 30 30S1 MC6060 1 HF37S1 15WER55 HF 29 29S1 29S2 30 30S1 MC6065 HF45 15WFR55 HF 30 30S1 MC7030 HF 38 15WER56 HF 29 29S1 29S2 30 MC7031 8...

Page 4: ...A2 A3 A4 SPKOAB AUX DL F H HIF LD LOF MS MU T TO IS4081 1 Walnut M D AM FM FM Stereo Phono Tape Note D2 169 579 CASS R P 969 56 8TK R P 969 55 A 1 A2 A3 A4 SPKOAB AUX DL F H HIF LD LOF MS M U T T O IS4081 2 Walnut M D AM FM FM Stereo Phono Tape Note D2 169 579 CASS R P 969 56 8TK R P 969 51 A 1 A2 A3 A4 SPKOAB A U X DL F H HIF LD LOF MS M U T T O IS4081 3 Walnut M D AM FM FM Stereo Phono Tape Note...

Page 5: ... HIF RS T TO LR919P Pecan C LL 3WR12X AM FM FM Stereo Phono Tape 49 1261 02 49 1251 02 8 8 2 8 2 3 169 586 8TK R P 969 51 A 1 A2 SPK A AFC AUX DL H HIF RS T TO LR919P1 Pecan C LL 3WR12X AM FM FM Stereo Phono Tape 49 1261 02 49 1251 02 8 8 2 8 2 3 169 571 8TK R P 969 51 A 1 A2 SPK A AFC AUX DL H HIF RS T TO LR920AE Antique Oak C LL 3WR12X AM FM FM Stereo Phono Tape 49 1217 01 49 1166 01 8 8 2 10 2 ...

Page 6: ... 8TK R P 969 54 A 1 A2 SPKOAB AFC AUX DL F H HIF LD LOF MS M U T T O MC6065 Walnut M AM FM FM Stereo Tape Note D2 Note B3 CASS R P 969 59 A 1 A2 A3 A4 SPKOAB AFC AUX DL F H HIF LD LOF MS MU T TO MC7031 Walnut M AM FM FM Stereo Note D2 Note B3 TM A2 A3 A4 SPKOAB AFC AUX DE DL F H HIF LD LOF MS MU TIO TM TS TZ MC7041 Walnut M AM FM FM Stereo Note D2 Note B3 TM A3 A4 SPKOAB AFC AUX DE DL F H HIF LD L...

Page 7: ...hangeability under some conditions refer to Product Features chart NOTE D SPEAKER PROVISIONS NOTE D 1 Models E9012 series G1000W G2000W W11 G3000W W11 G9012W1 G9014W G9019W H1000W series H2000W series H3000W series J1000W series J2000W series and J3000W series are 8 ohm Allegro Speaker Systems Allegro Models in the E9014 and E9018 series were 16 ohm systems A1 Model MC1000 Allegro 1000 Speaker Sys...

Page 8: ...76 G A R G T 2 5 142 196 56 641 03 0 4 X 0 7 D 1 5 3 0 2 7 6 2 7 or 76 2132 O f f M a n u a l A u t o m a t i c Repeat R o t a r y 7 12 R o t a r y 33 4 5 R o t a r y N o t e 5 11 1 4 Metal Gray Black N A Viscous Cue Slide 169 576 G A R G T 2 5 142 196 56 641 03 0 4 X 0 7 D 1 5 3 0 2 7 6 2 7 or 76 2132 O f f M a n u a l A u t o m a t i c Repeat R o t a r y 7 12 R o t a r y 33 4 5 R o t a r y N o t...

Page 9: ... or runs c o n t i n o u s l y in both Play and Record modes Selected by three p o s i t i o n slide c o n t r o l Four R Stops after f o u r t h program in Record o n l y Four R FF Stops after f o u r t h program in Record and Fast Forward o n l y Four R F F A Stops after f o u r t h program in Record and after all programs in Fast F o r w a r d Four B P R F F Stops after f o u r t h program in P...

Page 10: ...ng the three all sections of Models M C 7 0 3 1 M C 7 0 4 1 and M C 7 0 5 1 On the following pages are Feature Charts and Specifications Illustrations of the three models covered in this service manual of the three models appear below As will be noted from the illustrations styling is 8 ...

Page 11: ... 2 T R E B L E D D D H E A D P H O N E S T E R E O X X X BASS D D D E X T E R N A L A N T E N N A T U N I N G F F F F M 3 0 0 O H M B A L A N C E D X X X TUNER AMPLIFIER SWITCHES F M 75 O H M U N B A L A N C E D X X X P O W E R T T T A M X X X L O U D N E S S P T T A C O U T L E T S U N S W I T C H E D X X X HI F I L T E R P T T S W I T C H E D X LO F I L T E R P T T P H O N O G R O U N D T E R M ...

Page 12: ...ighten the screws until they are snug C A U T I O N Do not overtighten these screws as too much force may cause internal damage to the IC g Solder all leads being certain that solder does not bridge to other pins causing shorts which may damage the IC or external components 4 Do not operate these amplifiers without their proper speaker load 5 Do not short out the audio output of either channel whe...

Page 13: ...output ter minal of the Detector since there is alway some phase shift occurring in the R F IF or Detector circuits As a result Multiplex alignment made by a signal injected at the Detector input would not be correct For proper Multiplex alignment the composite signal must FM modulate the RF carrier and then be fed into the FM antenna terminals With the signal injected in this manner the Multiplex...

Page 14: ...d u l a t i o n Bandswitch in A M 17 S h o r t Test Point L A M Gang A n t e n n a Section T o Chassis G r o u n d 18 Test Point K A M IF I n p u t Generator O u t p u t Probe A V T V M Detector O u t p u t Across R 1 2 3 T e r m 1 0 4 4 5 5 K H z Gang Closed 19 Test Point K A M IF I n p u t Generator O u t p u t Probe A V T V M Detector O u t p u t Across R 1 2 3 T e r m 1 0 4 Rock Generator Whil...

Page 15: ... P o i n t A F M A n t e n n a Post Disconnect A n t e n n a 3 0 0 O h m 106 M H z 106 M H z C1E Set Oscillator T o Dial Scale 41 Test P o i n t A F M A n t e n n a Post Disconnect A n t e n n a 3 0 0 O h m 9 0 M H z 90 M H z L 4 Set Oscillator T o Dial Scale 42 Test P o i n t A F M A n t e n n a Post Disconnect A n t e n n a 3 0 0 O h m Repeat Steps 4 0 41 For M i n i m u m Change Set Oscillator ...

Page 16: ...ross R 1 1 0 6 0 0 K H z 6 0 0 K H z L101 If Necessary Align Antenna Stage 15 One T u r n Loosely Coupled T o A M Wavemagnet A n t e n n a None Detector O u t p u t Across R 1 1 0 Repeat Steps 13 14 For M i n i m u m Change Align Antenna Stage 16 One T u r n Loosely Coupled T o A M Wavemagnet A n t e n n a None Detector O u t p u t Across R 1 1 0 1000 K H z 1000 KHz R106 A d j u s t For A Reading ...

Page 17: ... d Scope B S c o p e C S c o p e Center Frequency Of Ceramic Filters Y 2 0 1 Y 2 0 2 Y 2 0 3 Gang Closed L 2 0 4 L 2 0 5 T201 A Preferred M e t h o d D i s t o r t i o n A n a l y z e r A t Test Point H S h o u l d Read M i n i m u m D i s t o r t i o n B A l t e r n a t e M e t h o d A d j u s t For Linear Scope Trace No Curve At Ends Of Trace Disregard Meter Reading C A l t e r n a t e M e t h o...

Page 18: ...C 7 0 4 1 holding the four feet 59 on M C 7 0 3 1 and 87 on M C 7 0 4 1 2 When removing bottom cover 2 note that the front edge of bottom cover must be inserted under lip of front frame when it is reinstalled FRONT PANEL ESCUTCHEON REMOVAL Certain components along the front edge of the chassis can be reached only after the front panel 3 has been removed 1 Loosen the alien screw recessed in tuning ...

Page 19: ...d lamp 4 Lamp is soldered to leads within grommet 5 Carefully pull lamp out of grommet 6 Unsolder lamp leads and remove lamp 7 Solder new lamp to leads 8 Press lamp into grommet being certain that it is fully seated 9 Press grommet firmly into light reflector 23 on M C 7 0 3 1 and 22 on M C 7 0 4 1 using a twisting motion until it is secure 10 Be certain that leads are dressed away from the dial c...

Page 20: ...ling outward 5 Remove five screws from the front panel 3 a Three screws 82 are located on the bottom b T w o screws 74 are located on the top 6 Remove front panel 3 by pulling outwards CONTROL CIRCUIT BOARD REMOVAL Most customer operating controls are mounted on one circuit board assembly 98 located directly behind the front panel 3 Proceed as follows 1 Remove the cabinet top 1 bottom cover 2 and ...

Page 21: ...not use excessive pressure when inserting and rotating the lamp sockets OUTPUT TRANSISTOR REPLACEMENT ACCESS Replacement of output transistors can be made easier by removing the output amplifier circuit board 95 and heat sink 10 as follows See Figure 7 1 Remove three screws 82 in mounting bracket 46 and another three screws 82 in bracket 47 2 Remove one screw 88 mounting output amplifier circuit b...

Page 22: ... OUTPUT STAGES See Figure 9 Each output channel of this model contains four transistors Q 1 4 0 1 Q 1 4 0 2 Q 1 4 0 3 and Q 1 4 0 4 in a differential amplifier circuit two predriver transistors Q 1 4 0 5 and Q 1 4 0 7 one bias transistor Q 1 4 0 6 t w o driver transistors Q 1 4 0 8 and Q 1 4 0 9 and two output transistors Q 1 4 1 0 and Q 1 4 1 1 Driver tran sistors Q 1 4 0 8 and Q 1 4 0 9 operate ...

Page 23: ... 7 0 1 When the closed contacts on relay K701 are switched open the circuit to the speaker connectors is opened When the over voltage is in the negative direction Q 7 1 0 will turn on and in turn Q 7 1 1 and Q 7 1 2 will switch on This will also deactivate Q 7 1 3 and relay K 7 0 1 thereby protecting the speakers FIGURE 11 MODEL MC7051 AUTOMATIC SPEAKER PROTECTION CIRCUIT 21 ...

Page 24: ...vercome the oppos ing voltages developed by diodes C R 7 0 1 and C R 7 0 2 This maintains transistor Q 7 0 7 at cut off If the load impedance drops below approximately three ohms the ratios change causing the emitter voltage of Q 7 0 7 to go negative and the base voltage to go positive This will forward bias Q 7 0 7 turning it o n When Q 7 0 7 conducts it will activate the remainder of the circuit...

Page 25: ...NOTES 23 ...

Page 26: ...00575 SPEAKER PROTECTION FUSE COVER 0043 862 00005 SPEAKER PROTECTION FUSE HOLDER MTS REF NO F1401 F1451 936 65 0044 841 00226 AM ANTENNA HOLDER R E F N O PART N O D E S C R I P T I O N 0046 812 01209 AM ANTENNA HOLDER BRACKET 0047 817 00311 DE EMPHASIS SWITCH BRKT CLAMP 0048 883 01036 ANTENNA TERMINAL STRIP 0049 844 00223 JACK CLUSTER PHONO CER L R AUX IN L R TAPE IN L R TAPE OUT L R 2 REQ 0050 8...

Page 27: ...204 820 01127 2 2UH CHOKE Q001 921 01108 FM RF AMPLIFIER TRANSISTOR FET Q002 921 01059 FM MIXER TRANSISTOR NPN Q003 921 01059 FM OSCILLATOR TRANSISTOR NPN Q101 921 01081 AM RF AMPLIFIER MIXER TRANS NPN Q102 921 01081 AM 1ST IF TRANSISTOR NPN Q103 921 01081 AM 2ND IF TRANSISTOR NPN Q201 921 01060 FM IF TRANSISTOR NPN Q301 921 01081 STEREO LAMP DRIV R TRANSIST R NPN Q302 921 01102 R CHAN MULTIPLEX F...

Page 28: ...FERENTIAL AMP TRANS NPN Q1402 921 01102 R CHANNEL BIAS TRANSISTOR PNP Q1403 921 01102 R CHANNEL BIAS TRANSISTOR PNP Q1404 921 01103 R CH 2ND DIFF R NTL AMP TRANS NPN Q1405 921 01104 R CHANNEL PREDRIVER TRANS PNP Q1406 921 01187 R CHANNEL BIAS TRANSISTOR NPN Q1407 921 01063 R CHANNEL 1 ST TEMPERATURE COMPENSATION TRANS NPN Q1408 921 01102 R CHANNEL 2ND TEMPERATURE COMPENSATION TRANSISTOR NPN Q1409 ...

Page 29: ...1458 863 02470 1 8 0 0 Ω 5 1 4W CARBON FILM RES R1459 863 02591 8 2 K Ω 5 1 4W CARBON FILM RES R1460 863 02676 6 8 Ω 5 1 2W CARBON FILM RES R1461 863 02469 1 K Ω 5 1 4W CARBON FILM RES R1462 863 02856 4 7 0 Ω ROTARY L CH BIAS CONTROL R E F N O PART N O D E S C R I P T I O N R1463 863 03110 2 7 0 Ω 5 1 4W CARBOM FILM RES R1464 863 02475 4 7 0 0 Ω 5 1 4W CARBON FILM RES R1465 863 02680 1 5 0 0 Ω 5 1...

Page 30: ... E F N O PART N O D E S C R I P T I O N 0053 926 00356 TUNING CAPACITOR SHIELD 0054 926 00384 TUNING ASSEMBLY SHIELD 0055 874 00053 VENTILATION SCREEN 0056 861 00481 VARIABLE TUNING CAPACITOR 0057 880 01287 DIAL CORD TENSION SPRING 0058 893 01182 CABINET RETAINING WASHER 4 REQ 0059 886 00329 CHASSIS GROUND LUG 0060 861 00447 12X4 2MM PULLEY 2 REQ 0061 825 00064 PULLEY RETAINING PIN 4 USED 0062 861...

Page 31: ...R B O N FILM R E S R110 8 6 3 0 2 4 6 9 1 K n 5 1 4 W C A R B O N FILM R E S R111 8 6 3 0 2 4 7 1 2 2 0 0 n 5 1 4W C A R B O N FILM R E S R 1 1 2 3 9 0 n 5 1 4 W C A R B O N FILM R E S R 1 1 3 8 6 3 0 2 4 7 5 4 7 0 0 n 5 1 4 W C A R B O N FILM R E S R1 14 8 6 3 0 2 4 6 3 1 0 0 n 5 1 4 W C A R B O N FILM R E S R 1 1 6 8 6 3 0 2 4 7 8 8 2 0 0 n 5 1 4 W C A R B O N FILM R E S R 1 1 7 8 6 3 0 2 4 6 9 ...

Page 32: ... 903 00384 L CHANNEL BIAS DIODE CR501 903 00429 RECTIFIER DIODE CR502 903 00429 RECTIFIER DIODE R E F N O PART N O D E S C R I P T I O N CR503 903 00379 RECTIFIER DIODE CR504 903 00379 RECTIFIER DIODE CR505 903 00379 RECTIFIER DIODE CR506 903 00379 RECTIFIER DIODE C019 822 02491 15pF 5 50V CERAMIC CAP C1401 822 02524 0 47uF 50V ELECTROLYTIC C1402 822 02584 330pF 5 50V CERAMIC CAP C1403 822 02417 1...

Page 33: ... 5 1 4W CARBON FILM RES R304 863 02488 100KΩ 5 1 4W CARBON FILM RES R428 863 02724 1 2 0 0 Ω 5 1 2W CARBON FILM RES R501 863 02691 2 7 Ω 10 1W METAL FILM RES R502 863 02475 4 7 0 0 Ω 5 1 4W CARBON FILM RES R503 863 02725 2 7 0 Ω 10 1W METAL FILM RES R504 863 02475 4 7 0 0 Ω 5 1 4W CARBON FILM RES R509 863 03050 2 2 Ω 5 1 2W CARBON FILM RES R902 863 02488 1 0 0 K Ω 5 1 4W CARBON FILM RES R903 863 0...

Page 34: ...CABINET RETAINING WASHER 4 REQ R E F N O PART N O D E S C R I P T I O N 0050 861 00433 TUNING CAPACITOR PULLEY BLACK 0051 880 01133 DIAL CORD TENSION SPRING 0052A 886 00363 SCREW TERM W BINDING POST PART OF REF NO 0052B 0052B 897 00306 MAGNETIC PHONO GROUND STUD 0053 883 01067 TUNING SHAFT RETAINING STRIP RETAINS REF NO 24 0054 854 00345 6 35MM NUT RETAINS REF NO 118 REF NO 52B 0055 844 00222 JACK...

Page 35: ...NE CAP C715 822 02602 8200pF 5 50V POLYSTYRENE CAP R E F N O PART N O D E S C R I P T I O N C716 822 02604 33pF 10 50V CERAMIC CAP C717 822 02610 1uF 20 50V ELECTROLYTIC C718 822 02617 100uF 35V ELECTROLYTIC C752 822 02529 1uF 25V ELECTROLYTIC C753 822 02499 220pF 10 50V CERAMIC CAP C754 822 02620 33uF 25V ELECTROLYTIC C755 822 03160 33uF 20 25V ELECTROLYTIC C756 822 02601 2700pF 5 50V POLYSTYRENE...

Page 36: ...ES R974 863 02489 1 2 0 K Ω 5 1 4W CARBON FILM RES R975 863 02713 6 8 0 0 Ω 5 1 4W CARBON FILM RES R E F N O PART N O D E S C R I P T I O N R976 863 02471 2 2 0 0 Ω 5 1 4W CARBON FILM RES R977 863 02486 5 6 K Ω 5 1 4W CARBON FILM RES R979 863 02592 4 7 0 K Ω 5 1 4W CARBON FILM RES R980 863 02485 4 7 K Ω 5 1 4W CARBON FILM RES R981 863 02584 3 3 0 Ω 5 1 4W CARBON FILM RES R982 863 02464 2 2 0 Ω 5 1...

Page 37: ...CUIT BD R E F N O PART N O D E S C R I P T I O N S P E A K E R P R O T E C T I O N RELAY P C B D C O M P O N E N T S CR701 903 00384 RECTIFIER DIODE CR702 903 00384 RECTIFIER DIODE CR703 903 00384 RECTIFIER DIODE CR704 903 00384 RECTIFIER DIODE CR705 903 00384 RECTIFIER DIODE CR706 903 00384 RECTIFIER DIODE CR707 903 00347 RECTIFIER DIODE C723 822 02595 0 22uF 10 10V ELECTROLYTIC C724 822 02595 0 ...

Page 38: ...L001 820 1176 TRAP COIL L002 820 1177 ANTENNA COIL REF NO PART NO DESCRIPTION L003 895 1096 RF COIL PRIMARY L004 895 1097 RF COIL SECONDARY L006 820 1178 COIL L007 895 1098 OSCILLATOR TRANSFORMER Q001 921 1159 RF AMPLIFIER TRANSISTOR FET Q002 921 1160 MIXER TRANSISTOR NPN Q003 921 1161 OSCILLATOR TRANSISTOR NPN R001 863 3023 100KOHM 5 1 4W CARBON FILM RES R002 863 3023 100K OHM 5 1 4W CARBON FILM ...

Page 39: ...NOTES 3 7 ...

Page 40: ...M O D E L S M C 7 0 3 1 M C 7 0 4 1 I C 9 0 1 IC951 B L O C K D I A G R A M M O D E L S M C 7 0 3 1 M C 7 0 4 1 IC201 B L O C K D I A G R A M 38 ...

Page 41: ...M O D E L S M C 7 0 3 1 M C 7 0 4 1 IC301 B L O C K D I A G R A M 39 ...

Page 42: ...M O D E L M C 7 0 5 1 IC101 B L O C K D I A G R A M M O D E L M C 7 0 5 1 IC201 B L O C K D I A G R A M 40 ...

Page 43: ...M O D E L M C 7 0 5 1 IC301 B L O C K D I A G R A M 41 ...

Page 44: ...NOTES 4 2 ...

Page 45: ... A N D P R E A M P CHASSIS W I R I N G A N D C O M P O N E N T S V I E W E D F R O M F O I L S I D E M O D E L M C 7 0 3 1 F U N C T I O N S W I T C H CHASSIS W I R I N G A N D C O M P O N E N T S V I E W E D F R O M F O I L S I D E M O D E L M C 7 0 3 1 F U N C T I O N I N D I C A T O R CHASSIS W I R I N G A N D C O M P O N E N T S V I E W E D F R O M F O I L S I D E 43 ...

Page 46: ...SS OTHERWISE SPECIFIED O C VOLTAGES SHOWN ARE MEASURED FROM CHASSIS WITH NO SIGNAL INPUT LOUDNESS SWITCH IN OFF POSITION L I N E VOLTAGE 1 2 0 V A C USING A HIGH IMPIDANCE DIGITAL MULTIMETER IC VOLTAGES IC 3 0 1 P I N M O N A U R A L S T E R E O 1 1 1 4 5 1 2 2 3 2 3 1 3 5 5 5 2 4 9 0 9 3 5 9 0 3 6 13 7 0 7 7 0 0 8 0 0 4 4 9 2 4 2 3 7 1 0 1 58 1 5 6 I I 2 2 2 4 1 2 2 4 2 4 13 2 4 2 4 1 4 3 3 3 2 I...

Page 47: ...O N O P R E A M P C H A S S I S W I R I N G A N D C O M P O N E N T S V I E W E D F R O M F O I L S I D E M O D E L M C 7 0 3 1 POWER A M P P O W E R SUPPLY CHASSIS W I R I N G A N D C O M P O N E N T S V I E W E D F R O M F O I L S I D E 4 5 ...

Page 48: ... N P U T LOUDNESS SWITCH IN O F F P O S I T I O N LINE VOLTAGE I 2 0 V A C U S I N G A H I G H I M P E D A N C E DIGITAL MULTIMETER IMPORTANT SAFETY NOTICE WHEN SERVICING THIS CHASSIS UNDER NO CIRCUMSTANCES SHOULD THE ORIGINAL DESIGN BE MODIFIED OR ALTERED WITHOUT PERMISSION FROM THE ZENITH RADIO CORPO RATION ALL COMPONENTSSHOULD BE REPLACED ONLY WITH TYPES IDENTICAL TO THOSE IN THE ORIG INAL CIRC...

Page 49: ...6 4 V 3 0 2 V 0 0 4 V Q 1 4 0 5 1 4 5 5 3 0 5 V 2 9 9 V 1 1 7 V Q 1 4 0 6 1 4 5 6 I I 6 V 0 4 8 V 1 1 7 V Q 1 4 0 7 1 4 5 7 0 0 1 V 0 0 1 V 0 7 8 V Q 1 4 0 8 1 4 5 8 0 0 1 V 0 02 V 0 7 8 V Q 1 4 0 9 1 4 5 9 0 5 7 V 1 1 7 V 3 0 8 V Q14 1 0 1 4 6 0 0 5 9 V 1 1 7 V 3 0 8 V Q 1 4 1 1 1 4 6 1 0 0 1 V 0 5 7 V 3 0 8 V Q 1 4 1 2 1 4 6 2 0 01V 0 5 9 V 3 0 8 V Q 5 0 1 1 3 2 5 V 1 3 9 V 1 4 9 V Q 5 0 2 1 3 8...

Page 50: ... A N D P R E A M P CHASSIS W I R I N G A N D C O M P O N E N T S V I E W E D F R O M F O I L S I D E M O D E L M C 7 0 4 1 F U N C T I O N S W I T C H CHASSIS W I R I N G A N D C O M P O N E N T S V I E W E D F R O M F O I L S I D E M O D E L M C 7 0 4 1 F U N C T I O N I N D I C A T O R CHASSIS W I R I N G A N D C O M P O N E N T S V I E W E D F R O M F O I L S I D E 48 ...

Page 51: ...POWER SUPPLY CHASSIS W I R I N G A N D C O M P O N E N T S V I E W E D F R O M F O I L S I D E M O D E L M C 7 0 5 1 P H O N O P R E A M P CHASSIS W I R I N G A N D C O M P O N E N T S V I E W E D F R O M F O I L S I D E 49 ...

Page 52: ... WAY IMPLEMENTATION OF THE LATEST SAFETY AND PERFORMANCE IM PROVEMENT CHANGES INTO THE SET IS NOT DELAYED UNTIL THE NEW SERVICE LITERATURE IS PRINTED T E S T P O I N T S A F M A N T E N N A I N P U T D 1ST F M I F I N P U T F M P X I N P U T G F M IF O U T P U T H F M D E T E C T O R O U T P U T K A M IF I N P U T L A M R F I N P U T M 1 9 K H Z O S C I L L A T O R O U T P U T S W I T C H E S SW 1...

Page 53: ...2 V 5 II 5V 6 3 6V 7 1 3V 8 2 8V 9 8 5V 10 0 V 11 12 2V 12 1 5V 13 0 7V 14 1 4V 15 0 V 16 1 0V IC 201 PIN N O V O L T A G E 1 2 0V 2 2 0V 3 2 0V 4 0 V 5 1 5V 6 5 6V 7 5 6V 8 5 6V 9 5 6V 10 5 6V 11 11 8V 12 3 7V 13 0 V 14 0 V 15 4 8V 16 0 V IC 301 PIN N O V O L T A G E 1 11 3 V 2 3 0V 3 5 1V 4 8 2V 5 8 2 V 6 8 3V 7 0 V 8 0 V 9 2 3 V 10 1 5V 11 2 2V 12 2 2V 13 2 2 V 14 3 2V 51 ...

Page 54: ...M O D E L M C 7 0 5 1 C O N T R O L A N D P R E A M P CHASSIS W I R I N G A N D C O M P O N E N T S V I E W E D F R O M F O I L S I D E 52 ...

Page 55: ... C H A S S I S W I R I N G A N D C O M P O N E N T S V I E W E D F R O M F O I L S I D E M O D E L M C 7 0 5 1 S P E A K E R P R O T E C T I O N CHASSIS W I R I N G A N D C O M P O N E N T S V I E W E D F R O M F O I L S I D E M O D E L M C 7 0 5 1 F U N C T I O N I N D I C A T O R C H A S S I S W I R I N G A N D C O M P O N E N T S V I E W E D F R O M F O I L S I D E 53 ...

Page 56: ...OR Q301 STEREO LAMP SW Q1457 PROTECTOR Q302 MPX OUTPUT Q1408 PROTECTOR Q352 MPX OUTPUT Q1458 PROTECTOR Q401 AUDIO 1ST AMP Q1409 DRIVER Q451 AUDIO 1ST AMP Q1459 DRIVER Q402 AUDIO 2ND AMP Q1410 DRIVER Q452 AUDIO 2ND AMP Q1460 DRIVER Q501 REGULATOR Q1411 OUTPUT Q502 REGULATOR Q1461 OUTPUT Q503 REGULATOR Q1412 OUTPUT Q504 REGULATOR Q1462 OUTPUT Q1401 DIFFERENTIAL AMPLIFIER IC201 FM IF DET Q1451 DIFFER...

Page 57: ...TOR Q301 STEREO LAMP SW Q1457 PROTECTOR Q302 MPX OUTPUT Q1408 PROTECTOR Q352 MPX OUTPUT Q1458 PROTECTOR Q401 AUDIO 1ST AMP Q1409 DRIVER Q451 AUDIO 1ST AMP Q1459 DRIVER Q402 AUDIO 2ND AMP Q1410 DRIVER Q452 AUDIO 2ND AMP Q1460 DRIVER Q501 REGULATOR Q1411 OUTPUT Q502 REGULATOR Q1461 OUTPUT Q503 REGULATOR Q1412 OUTPUT Q504 REGULATOR Q1462 OUTPUT Q1401 DIFFERENTIAL AMPLIFIER IC201 FM IF DET Q1451 DIFFE...

Page 58: ...FIER Q 7 5 8 MIC EQUALIZER AMPLIFIER Q901 AF 1ST AMPLIFIER Q 9 0 2 AF 2ND AMPLIFIER Q 9 0 3 AF 3RD AMPLIFIER Q951 AF 1ST AMPLIFIER Q 9 5 2 AF 2ND AMPLIFIER Q 9 5 3 AF 3RD AMPLIFIER TEST POINTS A F M ANTENNA INPUT H F M DETECTOR OUTPUT K AM IF INPUT L AM RF INPUT M 19KH2 OSCILLATOR OUTPUT D 1ST FM IF INPUT G FM IF OUTPUT F MPX INPUT T R A N S I S T O R NO DESCRIPTION Q1401 CURRENT SOURCE Q 1 4 0 2 ...

Page 59: ...CH S 3 F M MUTE SWITCH S 4 LOUDNESS SWITCH S 5 MODE SWITCH S 6 HI FILTER SWITCH S 7 LOW FILTER SWITCH S 8 MONITOR SWITCH S 9 SPEAKER SELECTOR SWITCH R 4 0 4 VOLUME R 4 0 6 BALANCE R 4 1 4 BASS R 4 1 7 TREBLE M O D E L M C 7 0 3 1 E X P L O D E D V I E W 57 ...

Page 60: ... S 3 FM MUTE SWITCH S 4 LOUDNESS SWITCH S 3 MODE SWITCH S 6 H I F I L T E R SWITCH S 7 LOW FILTER SWITCH S 8 MONITOR SWITCH S 9 SPEAKER SELECTOR SWITCH R 4 0 3 BALANCE R 4 0 3 VOIUME R 411 TREBLE R 4 1 7 BASS M O D E L M C 7 0 4 1 E X P L O D E D V I E W 58 ...

Page 61: ...M O D E L M C 7 0 5 1 E X P L O D E D V I E W 59 ...

Page 62: ...NOTES 60 ...

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