Hitachi HT 20 S Service Manual

Page 1

@ HITACHI

SERVICE MANUAL

SAFETY PRECAUTIONS

TY

No.245 EGF

HT-2OS

CONTENTS

SPECIFICATIONS ...... 1
FEATURES ........................ 3
SERVICE POINTS .................... 3
ADJUSTMENTS ....... 4
EXPLODED VIEW ...... 8
REPLACEMENT PARTS LIST ..... 9,11
CIRCUIT DIAGRAM ................. 10
PRINTED WIRING BOARD ............. 11

The following precautions should be observed when servicing.

1. Since many parts in the unit have special safety related characteristics, always use genuine Hitachi replacement parts.
Especially critical parts in the power circuit block should not be replaced with other makes.
Critical parts are marked with A in the schematic diagram and circuit board diagram.

2. Before returning a repaired unit to the customer, the service technician must thoroughly test the unit to ascertain that it is

completely safe to operate without danger of electrical shock.

SPECIFICATIONS

Type
Pl atter

Motor

Speed

SIN

Wow 81 Flutter
Effective length
Overhang

Tracking error
Adjustable force range
(scale)

Acceptable cartridge
weight
Lead wire capacitance
Accessory HITACHl
cartridge

Cartridge

2-speed belt drive system

Aluminum alloy dlecast, 310 mm outer
diameter

DC servo motor

2 speeds, 33-1/3 and 45 rpm

70 dB lDlN-B)

035% WRMS

220 mm

15 mm

20

0 - 3 9/1 turn of the balance weight
(directly readable in 0,1 9 steps]

4~9g
140pF

Dual magnet type (MTGS) (far U,S.A. &
Canada}

Movmg magnet type (M115) (except
U.S.At & Canada)

Frequency response
Output voltage

Channel difference
Channel separation
Tracking force
Stylus tip

Power source

Power consumption
Dimension

Weight
Other devices

10 7 25,000 Hz

25 mV (M735) or 3 mV (MT'15)

at 1 kHz 50 rnm/sec.

1 dB at 1 kHz

23 dB at 1 kHz

15 7 2.5 g (recommended 2 9)

Diamond stylus lDS-ST35 or DS-STIS)
120 V 60 Hz for U.S.A. 84 Canada standard
220 V 50 Hz for Europe standard

240 V 50 HZ for UK 8: Australia standard
110-120/220-240 V 50/60 Hz for Asia 8!
Latin America countries

3 Watts

435 1W) x 365 (D) x 110 (H) mm

(1771/8 X14~3/8 x 4-11/32

4 kg l8_8 lbs.)

Auto return, auto cut, antirskating, track-
ing force direct-reading balance weight,
viscous damped cueing.

SPECIFICATIONS AND PARTS ARE SUBJECT TO CHANGE FOR IMPROVEMENT.

BELT DRIVE TURNTABLE

February 1981

TOYOKAWA WORKS