Sansui SR 737 Service Manual

Page 1

1. BLOCK DIAGRAM

1) SR-737/SR-7090
Fig. 1-1 If" l
I MOTOR :
I
I ' FG SERVO CIRCUIT
I l r' --------- - " I I - - " - 'l
I SPEED ' ' SPEED PROPO- 53E AJGEENCY VOLTAGE I CONTROL '
I SENSER I I TIDIIAL PULSE CONVERTER COMPARATOR I I CIRCUIT :
I. _______ .I I. _ _ _. ______________ - _. J I I
_ _ _ _CB. ELL _S.E_BILO.CBQULT_ _I I I
{- I I ELECTRONIC I
1/4 DEMULTIPLI- PHASE I BRAKE I
I CATION COMPARATOR L _ J
I I -----
' I
' I
: CR GENERATOR :
L. _______________ J
IOTDR CONTROL CIRCUIT
Fig. 1-2 ." """""""""""""""""""""""""""""" I Ls-I--Ls-3 POSIIIDN SENSEPCOIL
I T'- 5 IBM; LSHC-g ORIva COIL
' - - - - I -.; IA IL
I 3 3 3 3 3 s : '
FG SERVO CIRCUIT 5 i I
. E i E
0 I I I
,- E i E
LEONE E I I L. ..... Ina:
's'p'E'EEI' TRANSISTOR I "1' I
SENSIR ......................................... .I
i I ..
I PLI. Hrs; ' r
5 83:50? 0 DIVIDER AND PIIAsE COTTPARATDRITTSTTSDIO)
. M , . V-
'I , ............... EEEEESEBIDEDchiC: ii: ............. I

oy.v

CR GENERATOR
FREQUENCY I D J

SST/1:869 PHASE COMPARAIO
5 OUIPUI ADJ m
SJIII'OII I
M 45.90:; 5

PLL SPEED SELECTOR SW J

L ......................................................

SR-737, SR-7090 Main Circuit

The electronic circuitry in this set is two servo circuits and a motor

control circuit.

This set employs both the F-G servo system and PLL servo system

by which rotation fluctuation is always locked in the reference
The servo circuit employs the PLL servo system and the speed signal.
control system (frequency-generator servo) together.

Page 2

2) SR-535/SR-509O

Proportional voltage
by motor rotation

Reference Voltage
voltage comparator
009

007

Generator Coils
Ln-1 , Ln-2, Ln-3

Befilar windings

Drivin Coils
Lm-1,-,ng2 Lin-3

001, 04
002. 05
003. w

Switching
circuit

Current si nal
generated y
position sensor

Position
Sensor

2. OPERATIONS 0F ELECTRIC CIRCUIT

A.SR-535/SR-5090

D.D. Motor of this direct-drive player system is DC blushless servo
motor having 20-pole on interior surface of the rotor magnet and
30 slots for winding stator coils, which ensure the performance
for extremely less wow-flutter and overload fluctuation. Namely,
driving operations of this 0.0. Motor connected with V.G (Voltage
Generator) servo circuit board are as follows.

Generator coils, Ln-i , Ln-2 and Ln-3 oscillate voltage pr0portiona|
by rotation speed of the motor. Voltage comparator compares the
voltage induced by rotation speed with reference voltage,5.l volts,
from printed circuit board, 5-0015. Control circuit, 008, restricts
current of driving coils by control signal occurred in the voltage
comparator, 009.

When this current flows by turn into one of three driving coils,
Lm-l, Lm-2 and Lm-3, the motor rotation speed varies to the
current proportionally. And, the induced voltage of three genera-
tor coils change proportionally by changing motor rotation speed.
ln other words, voltage comparator compares the voltage propor-
tional by rotation speed induced in generator coils with reference
voltage, 5.1 V,asa result, control voltage appears at one of collec-
tors of 009.This control voltage is provided for the purpose of
obtaining an accurate rotation speed of the motor free from load-
fluctuation of motor revolution.

As mentioned above, the motor is blushless outer rotor motor and
this outer rotor on interior surface is magnetized in order of
N-S-N-S poles regularly. The induced current by the rotor-turn
flows into one of driving coils. Namely, very weak high-frequency
signal, 83 kHz generated by oscillator coil, LOi, and capacitor,
CO7, adds to three position sensors. This sensor detects the turning
angle of rotor, and it generates current signal corresponding to
rotation angle which operates for switching circuits, 001, 002,
003, 004, 005 & 006, then it flows into Lm-l , Lm-2 and Lm-3
by turn, resultly, the current drives turntable (platter) to obtain
an accurate normal speed rotation.

Voltage Comparator

® iReference voltage 5.1 V

IProportional voltage
from generator coils
by rotatoin speed of
motor

© : Control voltage

Page 11

3) Exploded View

Parts List (Exploded View)

Part: No. Stock No. oaaeription Wanton Part: No. Stock No. Daaaripdon Poaition Para No. am No. Daaeripdon Poaieion
1 5312310 Speed Sdector Knob 53 5042090 Light Screening Plate 107 5182950 C5 Type Washer 20
2 5312390 Repeat 31 Record Size Knob (SR-737, 7090 only) 1% 5182570 P Type Thrust Washer 4a
7102111) Cuelno Knob Aas'y 54 5106143 SC Type Hex Socket Setscraw M3 1: 6 109 6003111 Spring, auto switch lever
(with 3. 4. 6 ~ 121 55 7092670 Tonearm 158535. 5850801 110 5182550 P Type Thrus1 Washer 350
3 5312320 Cmine Knob (ll 7092680 Tonearrn (SR-737. 88.70901 111 $03200 Spring (4). SS arm
4 5312361 Cueing 10100121 55 5132290 cs Typ. Washer 3. 112 5151004 E Type Washer 30
5 51(9122 31' Tvoe Screw M3 11 8 (812.737, 7090 only) 3 333% 3151109. SS arm
6 6502870 Cueing Khan (31 57 52324) Circuit Board How rm
7 5182970 CS Typo Washer 80 ($3,737. 7mg only) :15 @2180 Rem Wire
8 5232450 P Type Felt Washer (21 1020 58 7595621 50018 Circuit 8mm 11;: 3828383 2°1'W1LOLm base
9 5183340 P Type Nylon Washer 1020 (53.737 only) 118 6903130 ruler?k I:
1° 6903") 8° 5"""9 7595961 S0018 Circuit Board "9 5182960 cs '1'.- WW 2.
12 231239? 211211132: 5"090 °""" 120 6502810 Backvgvar
. . 59 7595601 50019 Circuit Board
13 59»? gmnruonst M4 18 59'737 M :22 3:10:49 EWQWW Se
1; 2232230 cfieamemer :5 759595 5009 Ci'w 8° 123 6502820 Disk Size 5.1mm
16 5312280 PitchControl Knob (SR-7090 MM 7062340 Repeat Cam Asa'v (with 124 ~ 130 l
17 5332091 Sansui Marl: 5° 5 33°20 31%.6'3" 73:3,. 124 5182970 cs Type Washer 80
' - ' 12 6012411 8 1 Cam
:3 212132320 3 3:: 3311244132 6 5903292 39"91c'm" °°°" W 122 5182270 08.919306 Wag; 4s
20 5120161 P Type Washer 46 59-37- 59-7090 W 127 5120161 P Type Washer 4a
21 5182361 P Type Washer M4 5 x 19 52 "02°90 3 ""°° '1' W" W 128 6903070 Spring, repee1 earn
22 5162700 8T Type Screw M311 10 50552 35 TV w '23 x 5182650 P Type Thrust Washer 620
23 6903270 Sprang Du cord 33 5903370 0" 59""9 A5 1" 9'13" 129 6012381 Repeat Cam 111
24 5103543 PT Type Screw M3 11 10 5 6903350 59""9- m m 130 6522070 Friction Washer
25 5032060 Shield Plate 35 6012520 am 0" 131 6903220 Sprlng 161, 111111 1eyer
26 5162700 8T Type Screw M3 14 10 55 5 5'00 5 TV WW 5 132 6502850 Link Lever
27 3910160 Nylon Cord Stopper 67 7052 am V W 7062350 nepee1 Grooved Cam than
28 2593661 80012 Printed Board for connections 68 690838) Spring, canoalar W (with 133 ~ 138 l
29 3810290 Pu Output Cord eu CSA 8s 69 905520 35 TV" w" 23 " 3 133 6903191 Spring 1:11. reverse cam
$103") PU o l '1COfd UL XX SR-737) 7 5103304 P TYDO SCN'W W X 6 135 6502 Rm Lever
9" ' 72 5124001 P Type Wamar 26,1111er cam p1a1e 135 6092020 RM, Cam
30 5101862 BSA Type Screw 11114 x 8 73 7012170 Lifter Cam Plate Aes'y (with 71 72 1 137 5,009 31» Two 5cm, M3 x ,2
200 W?" cm" W 74 6012510 Lifter Cam Asay 138 50,2363 aw 5mm Cam
W' , "' . 75 7052410 Lifter Lever Aasy (with screw) 1 m J 1111 ,m
31 5202181 Mechen.ce1 Cheese $05502 SSW mexs 12: 333293 3331351333. Ire
32 5151004 E TY mm. 3° 75 5105540 5F TYPP 591% M3 X 3 141 6512170 Repeat 1.11111 Arm (21
33 6903101 Spflnaxnuchm arm 77 6822260 Arm Rat Asa'y (with 76 , 142 5151 E Type Washer 3
3 65°28 0". V" 78 5052130 609.0011»! 143 6512160 aapae1 1.11111 Arm 111
983000 CS TV wm 2 80 5502770 Rm 145 6012450 Start Cam
83°30 " TV" Tm WW 2-5 81 6903120 Sarina. link low 146 5182960 cs Type Washer 2e
35 6592070 sw'm 0' 82 5151004 5 T1190 Wm 30 147 5182960 cs Type Washer 20
3° 5'5") E TV WW 3" 33 6502780 U W" 148 6903190 sermg 131 manual chock 1eyer
5182570 P Type Thrust WM 4.0. 84 5151 E Typa WW 3. 1% 6502780 mm. Chock LOW
37 5592051 Chm A 111 85 6512180 Reverse 1.11111 Arm 150 5132970 cs Type Washer so
38 6592080 Chmm Am (2) 85 5103543 PT TV! Smw M3 5 0 151 5232440 P Type Felt Wesher 111 8.20
39 5502750 Am "WW 87 5120161 P Type Washer 4a 152 6012440 Sm Cam
0 5183000 cs M M 2 38 515004 5 WP! W 34' 153 6502830 01.11 Size Select Arm
4 60124 Rm Cam 89 6&2040 Switch Fixing Board 15 SMB PT TY SC? M3 x 12
70mm T0110!!! D'Wing Boom ASS'V 90 $03140 Spring. switch fixing board 155 6912560 mum Wtight
m 2 ' 9 91 5103545 PT Type Screw M3 11 16 155 650274, 5mm LM,
2 55005 C TV! WW 0 92 5162720 PSA Type Screw M3 11 16 .57 85029,, cm, Am,
43 5106061 SF Tm Hex Socket Setseraw M4 116 93 5110241 H TV" Nut 3 153 5151 E Typew 4.
44 6012400 Tonearm DrMng Board . 94 1160250 Micro-switch 159 51511202 E Type Washer 20
45 M3241 Spring 8). .th Ofifl 1U" 01810 95 51am cs TYPO m 2. 160 5232420 P TY" NV'OD WW 2.
46 353288) Leadout Adjust Plate % 3532150 Link Rod (2) 181 22040 5 Trip (U990?)
47 6502901 Chm Holder 97 6502750 am Lem 6422050 5 Trip (Um, (SR-535. SIR-50901
8 6602891 96"? MW mm 93 55) 5 7" WW 3 6422060 8 Trip (SR-737 58.70901
9 502? WWW C 99 6012370 Manual Cam 162 m min 6." '
582990 W TY" Wash" 30 100 5182980 cs Type Washer 20 .53 3502360 am L,
5° 5101944 358 TV 5 5'3 " 8 . 101 5182330 P Type Thrus1 Washer-4e 164 5162710 PT Type Screw M4 11 8
51 7092690 TOM?! B. My (SR-535) WIth 02 W10 spring. 8!. W 165 4 0.0 Motor ($9535 SR )
7092770 TOWN 88 AS Y (SR-0) 54. 103 6mm Start Lew 32: an O D M010! (SR-737' 53-75mmo)
7092700 Tonearm Baaa Aa'v (SR-737) 69. 104 5151004 E Type Washer 30 ' '
7m27w Tonaarrn 88 ASS'V (SR-7M) 70 105 6502770 Auto Switch LOW
52 5109122 81 Two Screw M3 x 8 106 6903090 Spring, auto awitch 1ever
158.737, 7090 only)
r-- ! Abbrevlatlons fi- -
1. Pan Head Tapping 5. Pan Head SE MS 8 9. Flat Counter Sunk 13. Blfldm. Head 17. Tootnad Loch
5"" ----- PT Tyn- Scrow ----P$8 Tyne Wood Screw $5Ms 6 Screw Weeher1£111erne11
© W © m ............ c 1 ........ BSB Typo . . . .TLE Wash"
2. Washer Head 6. Bnndan. Head SEMS © W © W: © H
ppm 5"" F 5" "85' TV 10- Round Head Wood 14. Senna Washer 18. Wave Washer

........... WT Typo

@3:

3. Pan Head Screw
............ P type

90:2

4. Pan Head SEMS A
Screw , ..PSA Type

@309:

@011:

7. Bundm. Head
Screw ,8 TYPE

© .«-4

6. Flat Counter Sunk
Head Screw. .F Type

©E

Screw ....RH Typo

©¢~1-

11. Hex. Socket

6%

Satacraw . .50 T! ... ......... P Type
9 D V © 1
12. $101 Ty 16. Rotamon Rm.
Satacraw. .SS T1190 (5 1.1.21.3). .E Type
9 1:)

Q

1

f

15. Plan Washer

........ ....STypo

9/

19. Hexagon Nut
H Type Not

© 8

2