C.E.C. ST630 - Mechanism Operating Principles

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DESIGNATION

OF

PARTS

.

Dust

cover

.

Tonearm

Cartridge

.

Turntable

platter

.

Turntable

platter

mat.

.

Turntable

shaft

Hinge

.

Record

size

/

Safety

searcher

light

.

Record

size

/

Safety

searcher

crest

.

45

rpm

adapter

.

Neon

lamp

.

STOP

(®)

button

.

START

(<4)

button

.

CUEING

button

.

REPEAT

button

.

SPEED

SELECTOR

button

.

PITCH

CONTROL

knob

.

POWER

button

OMDNONAWN—

1.

SHOCK,

FIRE

HAZARD

SERVICE

TEST

CAUTION:

After

servicing

this

appliance

and

prior

to

re-

turning

to

customer,

measure

the

resistance

between

either

primary

AC

cord

connector

pins

(with

unit

NOT

connected

to

AC

mains

and

its

Power

switch

ON),

and

the

face

or

front

Panel

of

product

and

controls

and

chassis

bottom.

Lo

Zion

a

ee

NN

ee

mw

©

@

YM

®

®

(TaD)

Any

resistance

measurement

less

than

1

Megohms

should

Cause

unit

to

be

repaired

or

corrected

before

AC

power

is

applied,

and

verified

before

return

to

user/customer.

Ref.

UL

Standard

No.

1270.

Para.

66.

3.

D

(Mandatory

Test

after

servicing

Electrical

Appliances,

effective

7-1-83).

2.

MECHANISM

OPERATING

PRINCIPLES

(A)

RECORD

SIZE

SEARCHER

MECHANISM

An

optical

sensor

equipped

with

this

unit

automatically

searches

the

size

of

record

and

the

existence

of

record

as

well.

The

sensor

system

consists

of

the

lamp,

photo

transistor

and

the

slits

on

turntable

platter.

One

of

the

two

slits

on

turntable

platter

has

the

crest

which

works

as

a

shutter.

When

no

record

is

placed

on

the

platter,

the

photo

transistor

receives

light

from

the

lamp

twice

a

turn

through

the

two

slits;

when

a

17cm

record

is

placed,

the

photo

transistor

receives

light

once

a

turn

through

the

slit

without

crest.

The

pulse

of

light

which

photo

transistor

gets

is

transmitted

to

the

microcomputer,

and

the

pulse

of

light

is

sensed

as

the

size

or

the

non-existence

of

record

by

the

Microcomputer

(1C003).

Then

the

microcomputer

transmits

the

command-signal

of

speed

to

the

motor:

for

30cm

record

33-1/3

rpm,

for

17

cm

record

45

rpm,

for

no

record

no

rotation.

(B)

TRACKING

ERROR

CORRECTION

MECHANISM

The

tonearm

tracking

error

is

searched

by

the

Sensor

(PC201)

on

Phono

PWB

(67-1)

and

the

shutter

plate

mounted

to

the

tonearm.

The

sensitivity

of

the

sensor

has

been

adjusted

by

(VROO1).

No

tracking

error

point

has

been

settled

by

the

cor-

rect

positioning

of

phono

PWB

with

(VROQ2).

The

tracking

error,

if

occurs,

will

be

corrected

as

follows:

When

the

tracking

error

angle

is

created,

the

intensity

of

light

which

the

sensor

gets

will

be

varied.

The

variety

of

intensity

of

light

will

be

converted

to

the

current

which

flows

the

sensor.

The

degree

of

tracking

angle

is

almost

in

direct

proportion

to

the

current

near

0

degree

with

correct

adjustment

of

position-

ing.

The

current

will

be

converted

to

the

voltage

and

will

be

then

amplified

so

that

the

signal

amplified

starts

rotating

the

Servo-

controlled

Motor

(76).

The

rotation

of

the

motor

will

be

transmitted

to

the

Worm

Gear

(31)

by

the

Belt

(34).

The

Worm

Wheel

Gear

(35)

bited

the

worm

gear

will

roll

the

wire

so

that

the

Plate

Assy

(47)

on

which

the

tonearm

stands

will

be

moved.

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