Hitachi UD-1 Service manual

SERVICE

English

11

MANUAL

English

Deutsch

Frangais

No.

1155

l'

'-i.ì

.

'l

d.

Hitachi

uni-torque

a

double

.

performance

--

nisms..

Use

the service

for

since

same as in the UD-2.

standard chassis

system

tape

3-heads

deck

together

(No.

chassis

motor,

capstan

this manual

manual

the standard

the basic mechanism

UD-'l

for

mecha'

has

and a

higher

with

1139) UD-2

the

is

Das UD-1 Motor

DreikopfbestÚckung

zwei

Bandlaufwerk

Leistungsvermógen

kónnen. Diese

Wartungsanleitung

verwenden,

dem Chassis

Standard-Chassis

mit einem

ist

ausgerÙstet

Tonwel

Anleitung

len

auf,

ist

das Chassis

da

basiert.

UD-2

Hitachi

Uni-torque-

ein

besseres

139)

1

UD-1

weist

und

ausgesÎattetes

noch

um

gewahrleisten,

gemeinsam mit

(Nr'

mit

der

auf

et'

chàssis

Le

équipé

de

système à

les

interne

zu

zt)

soient

Utiliser

réparation

de

les

UD-2

de base

standard

du'un

tétes

3

double

perf

ormances

la

à

d'autant

cette

opérations

donné

étant

les mémes.

sonl

Hitachi

moteur

magnétiqúes

cabestan

des mécanisme:,

Platine

suPérieur'

brochure

(No

lI39)

faire

à

que

UD'l

uniqu'.

couple

à

et

Pour

magnétoPhon

le manui

avec

pour

le chàss

sur

mécanisme

les

d'u

qu!

toutt

'

TAPE

DECK

Fe

MECHANISM

I7I

1

b.

SPECIFICATIONS,

system

Track Motor

OUTLINE

ln

cassette

the

ance

the

Multi-pole

OF DEVELOPMENT

decks

are directly

motor

such

items

performance

DC

conventionally

advantages and

Hitachi

with

the

conducted

has

advantages

in developing

motor is

This

is constant;

smooth.

uni-torque motor,

A

players, addìtion,

circuit,

been

Fig.

(1)

has been adapted

single-chip

speed

developed

block diagram

3 is a

Servo control

A magnetic

motor speed.

the

magnetic

magnetic f ield, an electromotive

the

4-track 2-channel 2-moîor

. o

system

Capstan

Uni-torque

Reel disc

DC

erno

drive section

motor

r)

drive

DESCRIPTION

direct drive

using

wow &

as

the motor.

of

servo-motors

used for

d isadvantages.

research

of both

flat, brushless

a

a uni-torque

called

vibration

as developed

connected,

cassette

is minimized

motors,

flutter,

etc.

and AC motors

decks;

into direct

types of

servo direct drive motor.

DC

motor

for direct drive

for use in cassette

lC. which

control

cìrcuit

to minimize

induction detection cìrcuit

The

flux changes

contains

and motor

the number

lC.

of this

principle

when there is a conductor in

(DD

motor

section

(with

motor)

mechanical

*

This specif ication

OF UNI-TOROUE MOTOR

capstan

the

principal

so

depend directly on

perform-

have

they

motor and succeeded

because its

have

drive

various

motors

torque

and rotation is

record

decks. ln

the

drive circuit has

parts.

of

used is that

force

detector

speed

is

to detect

when

proportional

gov-

and

been

the

Tape speed Wow &

Fast-forward Rewind time

Heads

flutter

time

be changed

may

the

to

the conductor.

rate

of

As is shown

pole;

72 conductors under

Assuming these conductors arg numbered

generated

age is

46th, where

voltage is the

and 64th

55th

polarity

4.7Scm/s

0.03% wRMs

(C-60)

sec

90

(C-60)

sec

90 3-head

head,

system

(REC/PLAY

erase

combination

head)

for improvement without notice.

change of

l2t4

in Fig.

the magnetic flux

561A9

Fis. 1

1, there are 9 conductors for

the whole circumference.

'lgth.

in the 1st,

conductors

changes, and the direction

opposite

1Oth,

which are

for every other conductor, so

l7 l9

l5

t6

1-72,

28th, 37th,

positioned

directions of 8 voltages are same and added together.

When the magnet next conductor

A signal which

in

is

rotations of the magnet

turns,

sequence.

inverted

is

the voltage is induced

72 times

obtained.

the

number of

Since this

occurs

t8

of the

in

signal

each

volL-

the

in

(

Speed detect ion

(Magnetic

inductionl

Limiter

amplilier

Bolor magnet

-2-

Reference

vo ltage

Drive coil

English

72

Sped

detection

pailern

(-B

Differential

I

Hall elements

amp

-

lnput

stage

consists ference,

output even if

in the magnet.

The

pattern.

ed

(2)

Amplification, wave-shaping

signal

The

component

used amplified

circuit forms

it

a square wave

and

errors

voltages

of

it is

highly

a

there is any unevenness

conductors are arranged as a highly

speed detection

remains in

is.

as it

by an

Accordingly,

amplifier

it into a square wave

signal, any AM component

become

from 8

precise

signal

it,

with

negligible.

positions

signal with

the

of

has low

so

errors will

it is

high

on the circum-

a constant

or instabiliîy

precise prlnt-

speed detection

level and

over-saturated and

gain

signal.

an

occur

if it

and a shaping

By making

is llmited

AM

is

Fis.

_?_

3

(3)

Pulse

The

to

charged

The

nized with the

This

discharging

is

converted to a DC

(4)

Reference voltage,

The

reference

age is

reference, lization circuit

generator,

voltage

the

speed because

at îhe speed deteclion

pulse

trigger

f-V converter

the

of

generator generates

speed

signal

circuit and

DC voltage

output.

generated

voltage are

Since

its

stability is very

provided.

is

capacitor

it is repeatedly

detection

operates the capacitor

voltage by

comparison

compared and

the

is inversely

charged

frequency.

a trigger signal.

voltage

îhe

by

the f-V converter

reference voltage

of the capacitor

a low-pass f

amplification

a difference

important,

proportional

and

signal

synchro-

charging/

ilter.

and the

is îhe speed

so a

dis-

volt-

stabi-

English

(5)

Amplitude slicer

This slices current

the

amplified

amplifier. When the

speed, the

becomes

element

larger.

When

this operation

(6)

Drive amplification

The Hall

is

amplif ied by

ln

addition.

Since the

WBMS,

installed

it may rise to

incorrectly. Especially,

DD motor is affected

drive coil.

on the

plate

When re-assembling,

the

damage the

Pay

yoke plate

f

ixing

previously

attention

1) When

flutter

2l

Check

3) Clean

no

oil or dust adheres to

4l

Since

installed touch it.

output

larger and the width

voltage

speed decreases below the rated speed.

the

element signal sliced

an output

wow

&

incorporated

is

by the

To remove

screws.

marked lines

bearing;

to

the

the oil

the

guard

increases;

the thrust

pressure

the semi-variable

to

the

(limiter)

voltage amplitude

the output of the comparison

from

increases

speed

from

the comparison amplifier

of

amplitude becomes

is reversed.

by

B amplification.

class

transistor outside the lC

flutter

of this unit

more

in the

gap

and

adjust

positioning

and

yoke plate,

the

chassis before loosening

so

(a)

prevent

this value

than

since the drive

yoke plate,

that

the

(b).

and

dust

from

following:

washer touches

gap

it with

set

gap

roller,

of

the flywheel.

of approx. 1mm.

capstan and head, etc.

them.

resistor

plate

yoke

is

for speed

of the Hall

above the rated

the

slice of the

proportionally

the amplitude

ADJUSTING

is

as low as

if

wow

of îhe magnet

lines

Be

careful not

bearing,

control,

(a)

PC

mark

yoke plate

entering

the

on the

element

slicer

0.03%

parts

coil

of the

flutter

&

and

yoke

the

matches

the unit.

wow

so that

Board

do not

Hall

pro-

are

and

(b)

WOW

to

&

vides control

(7)

Generation of the driving elements

the voltage applied to the

of

Since the uni-torque

current, a Hall element is used

The

output

portional

ments and

voltage Vx of the Hall

to the current

strength B of

the

Alternating current is so the Hall element is

output. The output is amplified,

vided by the

Operation errors caused

coil.

by the thermal shut-down

lC

and the

& FLUTTER

síne wave

motor is

driven by alternating

for

lH applied

the

magnetic field.

generated

placed

here

signal is applied

by heat are

circuit.

Fis.

4

drive

by the Hall

switching.

elements

Hall

the

to

under

the

magnet,

to obtain the AC

speed control is

to the drive

prevented

plate

Yoke

is

coil.

pro-

ele-

pro.

Lubricate as follows.

Oil or dust the

capstan,

etc.

and the

should

pressure

head

during lubrication.

not

touch

roller,

transmission

flywheel,

parts

motor

LUBR ICATION

including

pulley,

belt,

-4-

1

2

Sliding

Apply

Shafts

PAN

parts

white

of rotary

motor

between

greases.

parts

oil

sliders and

and

bearings

the

chassis

English

t""'

1. Set this

Note

1

2. Reel

3

4

5

torque

Back-tensio n

Reel

& take-up roller

Brake

pressure

the

using a

pressure

the capstan.

torque

in the

unit

roller

type

fan

when the

Check

P

in the

tension

pressure

item

Take-up side

Supply side

Take-up

FF

Rewind

Take-up

Supply side

pressure

playback

direction

gauge,

roller

INSPECTION

side

mode and

arrow

of the

and

measure

is released f rom

OF MECHAN ISM

Reference value Remarks

l20

than

g-cm

s

than 15

g

g-cm g-cm g-cm

g-cm

4

g-cm

Note 2.

I

Note

Measure in Measure in FF Measure

Values when

Note 2

Set this unit

take-up roller

the

using a fan type

pressure

ìn

in

when

from the reel.

playback

REW mode

350-450

170-250

35-60

65-120

65-

Less

7-10

't00-140

More

press

the

mode

installing

the

in the direction

tension

the

playback

gauge,

counter

mode and

the

of

measure

and

press

arrow

the

the take-up roller is released

Fig.5

(

I I

)

'l

'--r/

Fis. 6

r_)

r'

I

)

-r"k"-uo

"r^

Head

plate

slider

-5-

Hitachi UD-1 Service manual

Specifications and Main Features

Frequently Asked Questions

User Manual