Technics SP 25 Service Manual

Page 1

ORDER NO. 807907-1586

Service Manual

QUARTZ
Direct Drive Turntable

SP-25

(M).(MC)

o The model SP-25 (M) is available in U.S.A. only.
0 The model SP-25 (MC) is available in Canada only.

Specifications Specifications are subject to change without notice.
Weight and dimension shown are approximate.

General Turntable speed
Power supply: 120 V, 50 or 60 Hz fine adjustment: 16% adjustment range
Power consumption: 1 1 W Starting torque: 1.5 kgcm (1.3 Ib-in)
Dimensions: 34.9 x 9.3 x 37.2 cm Build-up time: 0.7 s. from standstill
(W x H x D) (13-3/4 x 3-21/32 x 14-41/64 Braking system: Electrical braking
inches) Speed fluctuation due
Weight: 4.8 kg (10.6 lb) to load torque: 0% within 1.0 kg-cm
(at a stylus pressure of 200 g)
Turntable section Speed drift: Within i0.002% (33-1/3, 45 rpm)
Type: Quartz Direct drive Wow and flutter: 0.01% WR MS
Drive method: Direct Drive 0.025% WRMS (JIS C5521)
Motor: Brushless DC motor i0.035% peak (IEC 98A Weighted)
Drive control method: Quartzphase-locked control
Turntable platter: Aluminum die-cast, diameter
33.9 cm (13-11/32 inches) weight
1.85 kg (4 lb)
Moment of inertia: 250 kg-cm2 (85 lb~in2)

Turntable speeds: 33- 1/3 rpm and 45 rpm Rumble: -56 dB (lEC 98A Unweighted)
-78 dB (IEC 98A Weighted)

This rating refers to turntable assembly alone, excluding
effects 01 record, cartridge or tonearm, but including
platter. Measured by obtaining signal from built-in
frequency generator of motor assembly.

Panasonic Company Panasonic Hawaii. Inc. Matsushita Electric of Canada Ltd.
T h . Division at Matsushlta Electric 320 Waiakamilo Road. Honolulu. 5770 Ambler Drive.
eC nlCS Corporation of America Hawaii 96817 Mississauga. Ontario
One Panasonic Way, Secaucus, L4W 2T3

New Jersey 07094

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I CONTENTS

FEATURES ......................................... 2
ASSEMBLY AND SET-UP .............................. 2
PARTS IDENTIFICATION ............................. 3
HOW TO OPERATE .................................... 4
BLOCK DIAGRAM .................................. 5, 6
PRINTED CIRCUIT BOARD ........................... 7, 8
ADJUSTMENT ............. . ......................... 9

FEATURES

Oversized turntable that cuts off and absorbs external
vibrations

Based on analysis of the turntable vibration modes and
vibrations in the sound range, a Special viscoelastic material
is applied to the reverse surface of the turntable platter for
deadening.

The deadening material is applied to the undersurface and
outer periphery of the turntable platter, with the rubber
turntable mat on the surface settled into the turntable
platter. This design is superior in accoustic characteristics
even at high sound levels through elimination of turntable
resonance and absorption of external vibration.

Moreover, the oversized aluminum die-cast turntable
platter, 33.9 cm (13-11/32") in diameter, is heavy with a
moment of inertia of 250 kg-cm2 (85lb-in) for large
heavy weight 1.85 kg (4 lb) class design.

Vibration damping structure by the precision aluminum
die-cast cabinet and TNRC

The acoustical characteristics of the player system are
inevitably affected by the turntable platter and cabinet
employed. The SP-25 adopts an aluminum die-cast cabinet
superior in strength, with high processing accuracy.
Through cutting-off and absorption of external vibrations,
the unit is designed for improved acoustic characteristics,
with susceptibility to feedback minimized.

Quartz Controlled Rotation Accuracy

The SP-25 utilizes the oscillation of a quartz crystal as a
reference signal or source. This oscillation is not affected
by temperature change or power fluctuations. By sync-
hronizing the rotation of the turntable platter accurately to
the reference signal, speed drift of the unit is held within
i0.002% (33-1/3 rpm.).

Technics' unique motor construction in which the rotor of
the motor is integrally formed with the turntable.

High torque motor of 1.5 kg-cm with starting time of 0.7

second is capable of instant speed change-over Iat
33-1/3 rpm).

Stable and positive mechanism that can stand frequent use

for business use, etc. and a switch section with point
contacts.

Electronic brake.

REFERENCE VOLTAGE AND

WAVEFORM AT EACH IC PIN ........................ 9,10
SCHEMATIC DIAGRAM ............................ 11, 12
DEPLACEMENT PARTS LIST (Electrical) ................. 13
TROUBLE SHOOTING ............................... 14
EXPLODED VIEWS ................................ 15,16
REPLACEMENT PARTS LIST (Mechanical) ................ 17

I ASSEMBLY AND SET-UP

Caution: Use care not to damage the power supply cord
and bushing when setting up or installing the turntable into
a supporting enclosure.

Assembling is explained based on the Optional Technics
turntable base SH-1582 for reference in cases where the
unit is installed in another cabinet.

SH-1582 is provided with screw holes (4 places) for mount-
ing SP-25.

1. Install SP-25, with the screw holes aligned.

Screw holes

Fig. 1

2. Securely hold at 4 places by the screws supplied with
SH-ISBZ. (See Fig. 2.)

-

AC power cord i" Ground wire IGND)

Fig. 2 L

3. Pull out the power cord and ground wire IGND) from
under the turntable base.

4. After the above, install the turntable platter and turn-
table mat.