Technics SL 23 Service Manual

Page 1

ORDER NO. SD7509-104O

Service Manual

Player

SL-23-

Specifications

TURNTABLE SECTION
Type:

Driving method:
Motor:

Turntable platter:

Turntable speeds:
Wow and flutter:

Rumbw:

Speeds change method:

TON EARM SECTION
Type:

Effective length:
Overhang:
Tracking error angle:

F. G. SERVO PLAYER. Auto return
Belt drive

Dc motor with F. G. SERVO
Aluminium die-cast, 30cm(12')
diameter (with Strobo)

33-1/3 and 45 r.p.m.

0.05% W.R.M.S (JIS C5521)

0.08% W. zero to peak (DIN 45507)
-40 dB (DIN-A). -65 dB (DIN-B)
Electronic change

Universal "8" shaped tubular

arm. Static-balanced type. Direct

reading tracking force adjust-

ment. Anti-skating force control

and Viscous damped cueing

lever

220mm (8-21/32")

14mm (35/64")

Within +30 (at the point 150mm or
5-1/8" from the center)

Within-0.2°(at the point 55mm pr
2-3/16' from the
center)

Offset angle:

Adjustable tracking force
range:

Cartridge weight range:

CARTRIDGE SECTION
Type:

Frequency response:
Output voltage'

Channel separation:
Channel balance:
Load impedance:
Tracking force:

Replacement stylus:

GENERAL SECTION
Power supply
Power consumption

Dimensions (W x0 x H)
Weight

' Specifications are subject to change without notice for further improvement.

22°

0 to 49
13 to 179 (included head shell
weight)

Moving magnetic stereo cartridge
20 to 25000 Hz

3.2 mV(50mm/sec. 1 kHz, lateral)
4.5 mV(50mm/sec. 1 kHz. 45°)
25 dB at 1 kHz

Within 2dB at 1 kHz

50 to 100 k0

1.75 i0.259

EPS-27OED

~110/120/220/240V. 50 and 60Hz
3W

42.8 x34.8 x1 3.5cm
16-55/64x13-45/64x5-5/16 inches
65kg (14.3 lb.)

Matsushita Electric Trading Co, Ltd.
PO. Box 288, Central Osaka, Japan

Page 2

BLOCK DIAGRAM OF THE F°G°SERVO

* The output frequency which occurs at the F - G - section is in proportion to the rotation of the motor.
And this output frequency is amplified and converted to rectangular wave at pulse shaping circuit.

a: This wave is converted to trigger pulse and converted to rectangular having constant amplitude and
constant time base of Ts.

* This rectangular wave is in proportion to the rotation of the motor, too.

a: At next integrating circuit, this wave is converted to DC voltage Ti. This circuit controls the rotation of the
motor by changing the voltage.
If the speed of the motor is fast than standard speed, then the output frequency of the F'G -section
becomes higher so that the periodic time T of the constant time base becomes narrow, too.
Thus the DC voltage Ei will be increased.
The rotation of the motor is in proportion to DC voltage Ei. At voltage comparator, DC voltage Ei is
compared with refference voltage Es/n which is supplied through refference voltage reising circuit and
divider.
If the DC voltage Ei is higher than refference voltage Es/ n. This DC voltage will be controled to decrease
the rotation of the motor, and if lower than Es/n. DC voltage Ei will be controled to increase.

* At phase compensating circuit, to get more stable and accuracy rotation of the motor is feedbacked the
only AC component of the output signal from the motor driving circuit to the voltage comparator.

BLOCK DIAGRAM OF THE F.G.SERV6

T
T T T T T 5 Phase com-
E s M pensating

circuit

Ractangu- Tri or lus Constant Int rat- I VOItGQO Ec DC EC Md Em
Amp'm" '9 '3' "a clrgglt p L m be in egircuit °°'"°'a' " arl1pliflar__> F"mg
circuit generator 9 tor circuit
/ F. G (Frequency Generator) /
/ Es/n /
/ a erance 33 45 /
/ voltage E 5 Driver /
raising
circuit , 1/n /
4 1
Fig. 1

SL-23-(X)